August 26, 2013


Ketones and Carbohydrates: Can they co-exist?

Can you "carb-load" and stay in ketosis?

by Peter Attia

Read Time 7 minutes

For reasons I’m still struggling to understand, the idea of “nutritional ketosis” (NK, to be distinguished from starvation ketosis, SK or diabetic ketoacidosis, DKA) is often discussed and debated in much the same way as religion or politics. Perhaps this can be said of all nutrition, which is a shame.  Nevertheless, in my continued defiance of such sensitive topics, I’d like to add another layer of complexity and nuance to this discussion.

The “rule of thumb” for NK is that caloric intake is determined as follows (this excludes a subset of ketogenic diets known as calorie-restricted KD which, as the name suggests, is specifically restricted in calories):

  1. Carbohydrate (total, not “net”): less than 50 gm/day, but ideally closer to 30 gm/day
  2. Protein: up to 1 to 1.5 gm/kg, but ideally below about 120 gm/day
  3. Fat: to satiety

Let me illustrate what this looks like for Joe (left), Jane (middle), and Jeff (right — an example of a calorie restricted KD), three hypothetical people in NK — but each with different caloric requirements.


As a general rule, as caloric requirement increases the proportion of calories derived from carbohydrate and protein decreases (and the contribution of dietary fat increases), even while absolute intake of carbohydrate and protein increases.

Anyone who has bought a blood ketone meter knows how tough it can be to get “into” ketosis by carbohydrate restriction (since everyone asks, I use the Abbott Precision Xtra meter which uses two different strips: one for glucose and one for beta-hydroxybutyrate, or BHB).  Most practitioners consider the minimum threshold of NK to be a fasting serum level of BHB above 0.5 mM.  I’m a bit more stringent in my practice and like to see fasting BHB levels above 1 mM.   To give you a sense of one person’s numbers (mine), over a 6-month stretch in 2013, when I was in NK, my mean (i.e., arithmetic average) morning fasting level was 1.7 mM with a median value of 1.4 mM.  The highest morning level during that period was 5.2 mM.  (The highest morning level I have ever measured in myself is 5.7 mM.)

But, it took me a long time to get it right, especially since at the outset of my foray into NK I was consuming between 4,000 and 4,400 kcal per day.  (My average daily caloric intake for weight stability was about 3,800 kcal per day, which was validated by doubly-labeled water.)  I could still easily “fall out” of NK.  For example, on my daughter’s 5th birthday she insisted I have some of her tikka masala (contains lots of sugar), naan bread, and mango ice cream.  How could I say no to a birthday girl who insisted on going to the nicest Indian restaurant in San Diego?  As to be expected, the next day my BHB was 0.2 mM, and it took me 2 days to get back above 1 mM.

Here’s a little secret I’m about to let everyone in on… I like carbohydrates. I love sushi (though I now mostly eat sashimi).  I love Indian and Thai food, though I prefer to make curry myself to keep sugar out.  I make (and eat) the best hummus this side of the Nile River. I’ve figured out how and when I can eat them to meet the following conditions:

  1. Stay in NK (except on a few occasions like my daughter’s birthday);
  2. Increase my anaerobic performance;
  3. Preserve most (but not all*) of the benefits I enjoyed when I was much more strict about my ketogenic diet.

How, you ask? By learning to calculate my glycogen deficit.

(*) For me, the leanest body composition I achieved as an adult was in strict NK with no attempts to do what I’m about to describe below.  Since I’m not a model and nobody cares if my body fat is 7% or 10%, I’m happy to be a little less lean if it gives me the flexibility to increase performance and live a slightly more sane life.  At least for now.

PLEASE NOTE: I have never suggested, and can’t imagine I ever will suggest, that a KD is “best” or “right” for everyone.  What I describe below may seem extreme, both in the amount of work required and the actual application.  I fully acknowledge that (1) this is a highly analytical approach to eating, and (2) that I’m a “freak” (my wife’s words, not mine). I certainly don’t do this often, unless a lot is on the line (e.g., a big ride), but I like having this technique in my armamentarium.

If you’ve watched my presentation from 2013 at the IHMC, then you’re familiar with RQ.  Through years of metabolic testing I have a pretty good sense of my RQ at any moment in time – when I’m sleeping, when I’m sitting around (most of the time), when I’m riding my bike at 200 watts, when I’m riding my bike at 400 watts, when I’m lifting weights, etc.  This allows me to calculate what proportion of my energy I derive from glycogen and what proportion I derive from fatty acid.  Consider the following example:

If I ride my bike at an average of 185 watts (you’ll need a power meter to infer this) for, say, 2 hours, I know my average RQ is between 0.76 and 0.80.

The approximate formula is %CHO = 3.333*RQ – 2.333, which can easily be derived from the observation that %CHO utilized increases linearly from 0% at RQ 0.7 to 100% at RQ 1.0.

Furthermore, I know my VO2 at 185 watts is 2.9 liters per min, which means (using the Weir formula which I presented previously) my energy requirement was about 14 kcal per minute, or 1,680 kcal over 2 hours.  Hence, of these 1,680 kcal needed to pedal 185 watts for 120 minutes, 336 to 554 kcal came from glycogen.  In other words, I utilized between 84 and 138 gm of glycogen.

(By comparison, several years prior to being in NK, this effort in me would have taken place at a slightly higher VO2 – closer to 3.2 liters per min – and at a much higher RQ – between 0.90 and 0.95 – meaning the exact same work output would have required somewhere between 300 and 400 gm of glycogen!  That’s a real state of metabolic inflexibility.  Basically, I was entirely dependent on carbohydrates for energy.)

Since the first metabolic priority for ingested carbohydrate is glycogen replenishment, I can, in this setting, consume probably somewhere between 60 and 120 gm of carbohydrate following this ride and stay in ketosis.  Why? Because those carbohydrates are prioritized to replenish my glycogen stores AND I am highly insulin sensitive.  Note the *AND* in this last sentence. (The especially astute reader will realize some of this glycogen debt will be replenished by protein and glycerol, the latter of which is liberated by lipolysis – see post on fat flux for a primer).

Clearly I didn’t consume this amount of carbohydrate on my daughter’s birthday, so why was I out of ketosis the next day? Because my glycogen debt was not high.  Of course, I knew this and didn’t really care.  But, if I know my wife wants to go out for sushi one night, and I know she’s going to make me eat a California roll, I can “rig it” such that I show up to dinner with a glycogen debt appropriate enough to enjoy them without significantly interfering with my liver’s BHB production.

Extreme example

At one point, I did two tough bike rides on consecutive days.  Each day we rode 110 miles under challenging conditions.  Over 6,000 feet of climbing each day and very strong winds, which were either headwinds or cross-winds.  On top of this, we rode pretty fast. For the purpose of illustration I recorded everything I did and ate on the second day, which I rode a bit easier than the first day.

The second ride took 6 hours and 5 minutes.  My average normalized power output was 225 watts, and arithmetic average power output was 184 watts.  Based on mechanical work output, this required about 5,000 kcal.  Factoring in the other 18 hours of that day, my total energy expenditure was about 6,800 kcal for the day, obviously not an average day. (A detailed explanation of where the extra 1,800 kcal were expended is beyond what I want to get into now, but it’s basically the energy required to keep me alive – transport ions, contract voluntary and involuntary muscles, etc. — plus move me around, and digest food).

So what did I eat that day?

  1. Breakfast (pre-ride): 5 scrambled eggs, 2 sausage links, 3 pieces of bacon, coffee with cream.
  2. In ride nutrition (I spread this out over 6 hours): 14 oz (not a typo) of salted cashews, 2 Quest bars, 1 peach, 1 apple, 6 bottles of Biosteel High Performance Sports Drink, water. (Since I know someone will ask, I did not consume super starch this day since I was craving cashews as my carbohydrate source and was craving more sodium, given the 90+ degree temperature.)
  3. Late lunch/early dinner (post-ride): 2 oz ham, 3 oz pulled pork, large salad with oil and vinegar dressing, 2 slices of cheddar cheese, 6 mini hamburger patties, 2 tomatoes.

What did this amount to?

  • Fat – 351 gm, or 3,160 kcal of fat
  • Protein – 245 gm, or 980 kcal of protein
  • Carbohydrate – 321 gm, or 1,284 kcal of carbohydrate

(I used package information and Nutritionist Pro software to calculate this.)

Hence, on this day I consumed about 5,400 kcal in total at the following ratio:

  • Fat – 58%
  • Protein – 18%
  • Carbohydrate – 24%

By all conventional wisdom I should not have been in ketosis the next morning, right?

The following morning, my BHB level was 2.2 mM and blood glucose was 5.1 mM.

Teaching point I can’t resist: Following 2 days of significant caloric deficit, about 3,000 kcal in total, I should have in theory lost about a pound (mostly fat, possibly some muscle) which would have been noticed on a scale.  Instead, I gained 8 pounds over those 2 days! Sure it was mostly water retention, both from the glycogen (small) and the fluid accumulating in the interstitial space (“thirds space” fluid losses, large) due to a systemic inflammatory response.  This happens under extreme conditions of exercise.  In fact, the harder I exercise, the more weight I gain, transiently.  I am at my absolute lightest following 2 days of travel (i.e., rest).  So before freaking out at the sight of the scale, keep in mind that most day-to-day weight movement in our bodies is indeed water movement into and out of the plasma and interstitial space, respectively.

What’s my point?

Context matters!  If I ate even one-quarter of that amount of carbohydrate and two-thirds of that protein on a normal day – say, 2.5 hours of riding or 1.5 hour of riding followed by 1 hour of swimming, or a day of travel with no exercise – I would have been out of ketosis for two days or more. (Of course, my appetite on those days would not have allowed me to eat 5,400 kcal without feeling sick, but I won’t get into that until a later post.) But on this day, with these glycogen demands, I was able to maintain the perks of ketosis AND glycolysis simultaneously.

There are days, though, when I overshot my glycogen need and end up with a low BHB and high fasting glucose the following morning. Conversely, there are days I underestimate my glycogen depletion and wake up with very high BHB levels and very low glucose levels (i.e., BHB levels higher than glucose levels, when both measured in mM).

Final thoughts

I felt a bit like I was in unchartered territory because the literature on nutritional ketosis hadn’t really (to my reading) explored this level of extreme activity.  In future posts, I may write about other experiences and self-experiments, including my experience with exogenous (i.e., synthetic) ketones (which I did not use on this ride, but have experimented with on other rides – no, this is not “raspberry ketones” or other such gimmicks).

2017: You can read about one of my earliest experiences with exogenous ketones in this post.

Are carbohydrates necessary to produce 225 watts or more for hours on end? Yes. But, the key is knowing how much you need and when to take them.  A lower RQ at a given level of intensity means less demand on glycogen. In my experience, working with athletes and non-athletes, most tend to make two errors (for lack of a better word):

  1. They over-estimate their carbohydrate requirement, and/or
  2. They forget that no factor influences RQ – and therefore substrate requirement – more than dietary composition during lead up to event (or “life”, which is sort of the ultimate event).

Know your engine, first.  Then fuel it appropriately.

Photo by CloudVisual on Unsplash

Disclaimer: This blog is for general informational purposes only and does not constitute the practice of medicine, nursing or other professional health care services, including the giving of medical advice, and no doctor/patient relationship is formed. The use of information on this blog or materials linked from this blog is at the user's own risk. The content of this blog is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Users should not disregard, or delay in obtaining, medical advice for any medical condition they may have, and should seek the assistance of their health care professionals for any such conditions.


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  • Samantha

    From my own personal experience: I was training on the bike and running up to 28 hrs per week (given work schedules) and I was in NK for 4 weeks prior to my 24 hour mountain bike race at the end of July. After that race, I gained several lbs, but I knew it was glycogen/water retention. I continued to train and raced the following week, a short but very high intensity mtb race. After that, I RESTED. I decided not to race due to life situations and I had been neglecting my own research so I got back to writing/etc., and I went to riding about 5-10 hours per week. I lost not only 5lbs, but I went down a size in clothing during this rest period!! I also went out of NK, but now I’m going back in it because I feel awful when I eat carbs and I have more energy for my workouts and my research when I’m in NK.

    • Samantha

      Also, I wanted to add that I was not hungry at ALL the day the race ended (it was 12 noon to 12 noon, I slept for 8 hours at night due to heavy rains and a bad headache), and I was eating nonstop a few days after.

  • Jim Hunt

    Thanks for the insight doctor. I went and had my blood test done recently, and my insulin level is at 14 (even though the optimal level said it should be at 3-9. My HbA1C level was 4.8, but the optimal range is 5.6. Am I still in danger of getting diabetes? My doctor said to lower my carbohydrate intake and in take my vitamin D. I got a second opinion, and that doctor also said to lower carbohydrate intake and increase vitamin D. What do you think Dr. Attia? How can I get my insulin levels to an optimal level.

  • I think you have a typo in your “rule of thumb.” As written: “Protein: up to 1 to 1.5 gm/kg, but ideally below about 120 gm/day.” That first should probably be 1 to 1.5 kg/day?

    • No, that’s what I meant. If you weigh 70 kg, that 70 to 105 gm/day.

  • Debra Carroll


    Great article and information that I will be referring to in attempts to fuel my cycling, especially on the high volume weekends. You mentioned on thing that almost made me jump up and down….the weight “gain” after a hard weekend of training. I would love to have a clearer understanding of exactly what is happening in the inflammation you mention. With most of my heavy training on the weekends I have been aware for a long time that I could count on Monday being the heaviest day of the week and Friday being the lightest. My thought has been this was inflammation was in the muscle tissue but I’m not sure if you are saying its in the gut.

    • Grab a paper from the critical care literature. It’s called SIRS — systemic inflammatory response syndrome. Very well understood there, but poorly understood in the exercise world.

  • Fascinating post once again. I’m sure you’ve covered this elsewhere but why is it necessary to watch total instead of net carbs? Fiber is the difference between total and net, right? Does fiber effect ketosis?

    • In my experience, fiber still seems to impact ketosis, though less so. This is a general guideline, not absolute.

    • greensleeves

      Absolutely. Dr. J Slavin, the world expert on fiber, is very clear that most people digest a lot of it. Westman will tell you the same thing. Some does pass on through without impact – but far far far less than was previously thought. Google her research, read it all.

    • Nate

      I’m a Type 1 diabetic and I follow Dr. Bernstein’s low carb diet to help control my blood sugars. He recommends that diabetics use the total amount of carbs listed less only half of the fiber listed. This formula works well for keeping my blood sugars balanced with my insulin injections.

    • John

      Hello Dr. Attia,

      I’m a big fan of your work and especially your approach to nutritional thinking. I greatly appreciate your aim not to take so called “evidence” or “research findings” at immediate face value. I am one to think that all results must be studiously analyzed before drawing upon conclusions. I also believe when many separate sources reach the same conclusions it usually means there is strong truth to the finding. I have been on a nutritional journey myself, so to speak, but interestingly have arrived at the total opposite end of the nutritional spectrum. This New Years I resolved to become a low-fat vegan after reading The Starch Solution (John McDougall), The China Study, Blue Zones (Dan Buettner), and How to Prevent and reverse Heart Disease (C. Esselstyn), all of which advocate a high carbohydrate, low-fat, plant based diet. My main motivation for this was a pursuit of extreme longevity. And longevity in my opinion is one of the strongest biomarkers of vibrant health. Blue Zones explores the dietary habits of 4 of the longest lived peoples on earth that have the highest concentrations of centenarians. Okinawans in Japan, Costa Ricans on the Nicoya Peninsula, Sardinians in the Barbagia Region of Sardinia, and 7th Day Adventists in Loma Linda, California. I could go on for a very very long time about this, but to put it simply, each of these four populations eat a mostly plant based diet primarily based on starches and some legumes. For the Okinawans, roughly 69% of the diet is the Sweet Potato, followed by rice which is 12%, buckwheat 7%, and soybeans 6%, (fish < 1%) {US national archives} For the Nicoyans the food consumed at every meal is Corn (nixtamalized tortillas), black beans, and rice, plus some citrus fruit and the occasional chicken). For the Sardinians by far the main food is flatbread made from barley and potato about (1 kilogram/2 pounds daily), plus fava beans, minestrone soup and meat once a month or so (goat). Finally, the 7th Day Adventists in California are primarily vegetarian as their religion discourages animal foods, alcohol, and very flavorful foods. Most of them eat oatmeal for breakfast. I'm curious what your thoughts are on this as the combination if these four books has given me (seemingly undeniable) evidence for a plant based, starch centered diet. On the subject of obesity I also noticed that the lowest rates of obesity were found in parts of Asia where the most rice is eaten.
      Obesity Rates: Vietnam 0.5%, Indonesia 2.4%, China 2.9%, Japan 3.1%, South Korea 3.4%, Philippines 4.3% and Singapore 6.9%(CIA Spotlight on Obesity Rates). Vietnam has lowest obesity rate in the world and the second highest rice consumption per capita in the world. Also, rice is traditionally eaten at every meal in these countries, especially Japan and Korea. In China there's even a greeting that means "have you had your rice today?" And the word for food literally means rice. It seems to me that the elimination of unnecessary fat from the diet yields a much greater result than the elimination of carbohydrates (as expressed in the ratio of 1g carb=4 calories vs 1g fat=9 calories) I apologize if this is a repeat topic for you, but I wanted to know your thoughts on these specific points and possibly your thoughts on the Starch Solution and Blue Zones.
      Also, I'd be happy to provide reports/records from which I got this data if you would like to fact check as I realize a portion of what I mentioned is anecdotal and was derived from conversations in the Blue Zones book.

  • PhilT

    Awkward question from the UK – we actually analyse for carbohydrates on our labelling systems, and separatley analyse for fibre. The US has total carbs as what’s left after removing fat and protein from ash free dry matter, so it includes fibre hence the whole “net carbs” thing.

    Should we consider carbohydrates plus fibre as “total carbs” in the above context ?

    • I count total carbs inclusive of all carbs, including sugar and fiber. Just makes it easier to keep track of, though obviously fiber and sugar are treated very differently.

  • Hey Peter. Thanks for everything you do. I’ve taken my max distance from 5 miles in April to 80 miles yesterday, along with 40 pounds lost since late June.

    Although you introduced the topic by discussing rather high Glycemic Index foods like sushi and sweets, I didn’t see much of a mention of this in the later parts of the post. Would you mind discussing this more?

    I’m a bit of a burger fiend. I’ll admit, I do love my buns (as much as their high GI tells me no). Say I stopped for a burger in the middle of a long ride, would this impact ketone production, in comparison to something like nuts or super starch?

    • I don’t understand your question. I listed out what I ate on the ride. If you’re asking me if I eat bread and such, the answer is almost never.

    • I’ll rephrase: Would it be detrimental to my ketotic state to eat simple carbs (such as bread, rice in sushi, sugar, naan, mango ice cream) mid-ride? Or do you advise sticking with lower-GI carbs like nuts, super starch, etc?

      • Yes. Stay with the complex ones. Much easier on gut and better glucose profile.

    • Another question… I noticed that you didn’t list MCT oil in your breakfast. Is your consumption implicit, or did you exclude it for a reason?

      • I usually don’t travel with MCT. This event was in NorCal and I live in SoCal.

  • Another fantastic article! Thank you very much for taking the time.

    How do you calculate the actual protein you are eating?

    Nutrition information from Self shows a 297 gram rib eye to equal 68 grams of protein. Do you use the 297 grams or the actual protein?

  • GeoC

    Peter, thanks for again producing an exceptional nutritional educational piece.
    If you have time, your comments on the article “Inhibitory effect of dietary lipids on chaperone-mediated autophagy” would be greatly appreciated.

    • If I have time? Funny guy.

    • GeoC

      From the abstract: “Our findings identify a previously unknown negative impact of high dietary lipid intake on CMA and underscore the importance of diet composition on CMA (chaperone-mediated autophagy).

    • Jay Fox

      Interesting, I’ll have to find the time to read the full article. Just from skimming it, I see that the “high fat” diet was 60% fat (by calories), and 5% by cholesterol?? Is that a typo? How much cholesterol is that, anyway? I’ve never seen cholesterol and calories mentioned together, probably because, even if it had the energy density of fat, there’s just not enough of it to matter.

      While I’d be interested in Dr. Attia’s take on this, you might want to see if the “other” high-fat Peter, over at the Hyperlipid blog, has had a chance to review this.

      I’m reading his blog from the oldest posts going forward, so I’m still a few years back, and this study appears to have been published only last year. So if he has reviewed it, I haven’t seen it yet.

    • Rob Coberly

      That looks like careful work, demonstrating modulation of CMA by lipids in those models. In that work, there is no examination of ketone body effects, of course-not what they were studying. We can’t know if the subject animals had significant levels of ketone bodies, but it seems very unlikely from what information is given about the diets used. But there is also good quality evidence that ketone body concentration positively affects CMA:

      Ketone bodies stimulate chaperone-mediated autophagy.

      Proteolytic and lipolytic responses to starvation.

      One point I keep in mind is that nutritional ketosis promotes biochemical adaptations resembling what happens in calorie restriction or negative energy balance. The process changes many biochemical variables, so would likely affect the results in metabolic research. And so far, only a small proportion of the research literature has explored the many questions of interest using models that specify CHO intake or quantify ketone levels. I’m watching literature on calorie restriction and the fasting state too, for clues.

  • Nakort Valles

    Awesome post, I have read that some types of carbs are better for restoring muscle glycogen, exp: fructose is bad, but glucose is good, have anything to add on that?

    • I much prefer glucose to fructose for glycogen replenishment for reasons I’ll get to later.

  • Venev

    This post answered an important question that was bothering me. Thank you Dr. Attia for your blog. Keep up the good work 🙂

    • I’m always happy when I can proactively answer a question.

  • Tom Ashbrook

    Well done Peter. I know you are busy but selfishly I, and assume thousands of others, miss the old days of weekly posts!

    You are on the cutting edge and I wish more people involved in sports performance would share your enthusiasm for what really matters given what we have (genetics, schedules, goals, etc.). I see way too much one size fits all with kids in sports like swimming. It’s tough to tell a 13 year old swimmer about nutrition, lactate threshold training, REE, etc. when you conflict with the dogma that is out there. Strike that – it is impossible and it would have been for me too at that age. Especially from my dad. What I would not give to have this information many years ago! At least I got my soccer player son off of Gatorade and on to water and, begrudgingly, a dash of UCAN for those longer two-game days.

    Thanks for your efforts. It is a somewhat subtle point about context but it makes all the difference.

    • Thank you, Tom. I have no idea how I was able to crank out one post a week for so long. It takes every ounce of will power I have to write one a month now with current schedule.

  • Jacob Jaglarski

    Very intriguing and insightful, Dr. Attia. I wonder how this would translate over to muscle building in a ketogenic state, if one were to try and stay in ketosis for neurological issues. For instance, I largely follow the Body By Science protocol of exercise (with some variations) while wearing an elevation training mask and doing rest-pauses and what not – it’s highly intense, but brief. I’ve been more or less following a cyclical ketogenic diet, but I’m wondering if I can alter my feedings on this day to still register at the minimum of 0.5mM of ketones. I could probably still gain muscle, albeit slowly though.

    Dr. Attia, I would recommend you read this blog post: Ben Greenfield has referenced it a bit before his ketogenic Ironman experiment post. Don’t get confused by the title, it’s actually displaying how and *why* one might want to fuel performance with fats instead of carbs. I think after I re-read your post a few times and digest it, I might go back and re-read this and get a better understanding for recycling D-Ribose and creating glycogen deficits so I can fuel performance better while still maintaining relatively strict ketosis. I assume ample consumption of Dave Asprey’s MCT and Brain Octane Oils would help, though, lol.

    Again, thanks for the great post. Ironically I was reading through your blog yesterday and was disappointed that you hadn’t blogged in awhile, but thought to myself that even though they don’t come one day after another, they’re the most quality blogs around – and that’s what matters. Keep em coming!

    • Interesting. I’ll try to check it in out at some point. Not sure when, of course.

  • N

    Fascinating article. I have been experimenting with LCHF for the past month or so – eating carbs only in the form of veggies, protein <100gm per day, and fat to satiety.

    I run ~60 miles/week. During the first week of this diet I was able to maintain mileage with some loss in pace. During the second week I felt completely wiped out and struggled a lot with even 5 milers. Sometime during the third week I reintroduced a few carbs at night (strawberries and cream, or maybe a cup of plain full-fat yogurt), and noticed a turnaround almost immediately. I was able to resume my mileage right away and feel pretty decent all around (I do feel weaker on steep climbs). I suspect this has to do as much with fat-adaptation, as with the reintroduction of carbs.

    My question is this. For someone who is not interested in ketosis per se, but rather wants to maintain a high-level of fat-burning for endurance performance, how would you suggest approaching the carb-intake issue? Post-exercise? Night before a big bout of exercise? Could you provide some guidelines (I know it cannot be precise) around how much is too much, and what quantity or carbs would be in the "safe range" (to keep fat-burning alive, while still enhancing performance by repleting glycogen stores)?

    Thanks for all you do – and for sharing it so generously!

    • Basically it’s the same approach, but less restrictive. The fewer carbs you eat, the lower your resting and exercising RQ. So look to replace glycogen, but little more. As RQ goes down, so too, does CHO requirement.

  • Todd Williams

    I recently tried NK and I love it. It’s been a couple of weeks and I feel great. I’ve got two questions though:
    – If I end up eating too many carbs in one meal, is it even worse that I’m consuming so much fat with it?
    – I do CrossFit every morning, similar to your tire flipping, box jumps etc., but I don’t do any of the marathoning that you do. Do you think NK will sustain me for these short 15-minute high-intensity workouts or should I look to add a few carbs post workout? I’ve noticed a bit of a hit to my performance, but then I’ve only been in ketosis for 2 weeks.

    Thanks Peter! Your work has truly changed my life.

    • It can be done, but requires care and time to adapt. Probably also some benefit from supplementing creatine and using *very* high quality BCAA.

    • Nico Ritschel

      Are there any brands of BCAA that you recommend? I’ve heard that many suppliers use less-than-ideal ingredients to begin with.

      • Only one I touch is BioSteel, which contains very high quality BCAA in their “high performance sports drink” I reference. Most BCAA over the counter are, in the words of the folks I know in the industry, “crushed bird feathers.” Beware.

    • Bill

      Peter, at some point it would be wonderful to hear your views on protein, carbs and high-intensity strength training, which I know you also do. Both the NK’ers and simple LC’ers like me would likely benefit.

      Immediately after a very brief but intense 1x/week full-body strength workout (like today!) I’m pretty sure some high-quality protein is advisable, but not sure whether or not some extra carbs would help to replenish glycogen and facilitate muscle supercompensation. Most bodybuilders seem to think so, but real evidence seems to be scarce.

      • Just read a review article on this recently. No evidence post-lift CHO plays any role in muscle synthesis. Protein is sufficient.

  • Alex F

    Thank you for this post.
    I’m a low-carber, medium-length endurance guy. I’ve had the hardest time working in carbs to refuel during and after exercise. It seems to quickly shift me right back into the carb-craving, blood sugar-swinging person I was a year ago (before adopting a paleo diet). Then it will take days to break this cycle.

    I know I need extra carbohydrate to sustain my level of training, but I really wish I didn’t. I’m still learning how to work them in. This is helpful.

  • Edel

    Hi Peter and thanks for your blog. I am eating low GI with a view to possibly trying NK in an effort to see if it brings about a regular menstrual cycle, in addition to bother benefits (not sure what you make of the limited literature on ketogenic diets for PCOS). I’d like to know if you experienced drastic changes in bowel health when you changed the macronutrient composition of your diet drastically? I think my gut is shocked that it isn’t getting cereal grain fiver, but instead is getting fibre from vegetables and limited amounts of low GI grains. Thanks

    • Yes, my gut does not “like it” when I do a lot of fructose (from fruit). In reality, my gut seems least happy any time I’m eating CHO, though I tolerate veggies very well, and nuts ok.

  • Edel

    I meant ‘other’ benefits not ‘bother’

  • Jeff

    Hi Peter
    Very interesting, I’d like to see you power meter files.

    My own 3 week experiment was a bit of a bust, I was never able to get into NK, must have been the protein although my wife basicallly eating the same diet as me had no problem and she was doing no exercise. She was also able to easily track going into/out of NK after a night binging on popcorn at the movies with our kids, about 36 hours to return to NK and did it twice.

    After 3 weeks of almost no carbs I lost no weight every morning 155 to 160 lbs.

    I seem to function best between 50 – 100g of carbs a day no matter how hard the training is. I think most cyclists overdue the carbs.

    Maybe when I have a whole month without racing I’ll try it again and measure all my protein.

    After going back on carbs (am I on the wagon or off the wagon) I did repeat as State Champion in the kilo individual pursuit.

    • Interesting. If you’re doing very well in kilo, I don’t see NK offering any advantage at the kilo, outside of training, perhaps. You’d laugh at my power files, I can assure you!

  • This is very interesting to me. I just wrote a post in a similar vein about how I finally started getting consistent high blood ketones through daily exercise (described in the post): Deeper ketosis without protein restriction. My conclusion is also that it’s about glycogen depletion. I’m very pleased because the protein restriction necessary to keep me in ketosis previously was also making me feel hungry and irritable, which seemed counter to health, and which I was not willing to sustain.

  • Klemens

    Great post and very interesting.

    Just a short question on your cashews intake: are you concerned about the omega6 intake and the pro inflammatory effect, also in light of the high intensity sport effort being inflammatory in itself?

    • Perhaps somewhat, but the data are so unclear.

  • Valerie Wilson

    I find your ketosis experiment very interesting. I realize your can only talk about your own experience, but do you have any knowledge on lean women do with ketosis, especially considering long term hormonal health? I tried ketosis a few months ago, but it seemed to mess up my hormones. I have wondered if I just wasn’t eating enough, even though I seemed to be eating tons of fat.

    • Not beyond my work with female patients.

    • Erika

      As a female athlete who’s been eating paleo for over a year, I find that it is actually pretty difficult to get enough calories to avoid hormonal issues, at least while training heavily and on the strict version of this diet. For me, I add fruit whenever I crave it, and even true starches when I feel particularly exhausted (and the few days before my biggest events). But personally, I eat to feel and perform well, not to hit specific target numbers, and your goals may be different.

  • Awesome insights, as always, Dr. Attia.
    I try to tell people that, on a biochemical level, the best (or “safest”, if you will) time to consume carbohydrates (especially higher GI/GL ones) is right after a hard workout. And no, walking around the neighborhood doesn’t count! This assumes they’re already mostly LC and fat-adapted, of course, but I suspect that even for the average SAD-eater out there, the post-workout window is still the safest time to eat carbohydrates, especially if they can manage to do something pretty intense first thing in the morning, fasted. You’re so right — so much of how much carbohydrate we can tolerate has to do with our glycogen stores: Already full? Empty or close to it? Completely different ballgame. Anyway, I like to think of it this way: if you want to eat a couple of cookies (or insert one’s sugary vice of choice), you’ve got to *earn them* (via hard workout.)

    I’ve suspected the glycogen issue for a while, and you just confirmed something I’ve noticed in myself for many years that at first *seems* illogical, but completely rights itself when you understand human physiology: I’m often my leanest after a day or two of NO workouts. (And eating well, of course. I suspect the leanness wouldn’t be there if I skipped the gym and coupled it with a carbfest.) So yeah, it’s the temporary inflammation/edema caused by the hard workouts themselves. When the body gets some time to rest, it dumps the excess fluid. This also explains why I looked so PUFFY in the finish line pictures of the two marathons I completed in a former life. Well, that, and the fact that they were both long before I knew anything about LC, and was following all the standard advice to “carb load,” never mind that some of my training runs early on were only 6-8 miles. Pretty sure I didn’t need all that pasta & rice! 😉

    I wish every female exerciser could read and understand your work — especially that little teaching moment about scale weight. We’ve GOT to get young women OFF THE %$^*&#$ SCALE! That number is *not* the sole determinant of fitness, health, strength, and certainly not self-worth. People who work out and are concerned with their health place far too much stock in that one shoddy number, and that number is subject to more ups and downs than a kangaroo on a trampoline.

  • Jen

    That was really interesting! My family is going to San Diego this winter…wondering if you’d let us know what restaurants have the delicious Indian food and sushi?

    • I don’t recall the names of either. Indian is downtown. Sushi is in Encinitas (hole in the wall place).

  • Kory


    It’s always great to read more about your N=1 trials. I too have been doing my own testing and have been learning similar lessons. I am type I diabetic (for the past 11 months) and have been on an insulin pump for the past 6. The pump allows me precise control over my insulin levels – which presents a fairly unique ability to manipulate my insulin levels. I am also an endurance athlete so I find your ability to relate your nutrition to performance extra interesting. This latest post about glycogen debt comes at just about the same time that I’ve been coming to those conclusions about myself.

    Once I get going with longer rides, the following few days I feel so much stronger without a need for a long warmup. I have been avoiding too much high intensity work since that actually tends to spike my blood sugar. It’s a delicate balance between turning my pump down for endurance rides on the bike and I’m yet to master the proper pump rates for running. Gears on a bike make things much easier to moderate. I’m a large athlete 6’5 220, 10-12%bf, so running is more anaerobically demanding than cycling.

    I’m curious if YOU had to the ability to control your insulin levels, which experiments would you be interested in trying? It might be somewhat irrelevant to the situation, but I suspect it’s not. (certainly not to my unique situation).

    One of the questions that I’ve been wondering and suspect I have an working model on is whether it’s the the amount of carbs, insulin level, or blood sugar level that actually drive the body into ketosis. For a while I was fearful of bolusing with too much insulin for fear of inhibiting ketones, but now I feel like it’s the glucose that must be burned through first before my body will burn get to producing enough ketones.. It’s still a work in progress and likely a bit of teasing both at the same time.

    I’m hoping you might take some interest in my unique situation, but I imagine everyone feels that way. Any recommendations are welcome. So far my experience with ketosis has been a godsend with the stability that it provides.

    • Very interesting question, Kory, but I can’t play endocrinologist over the internet. Sorry.

  • Dan Walker

    For someone who is HIGHLY, HIGHLY insulin resistant and does not exercise, but their pancreas is still cranking out the insulin by the gobfull, is it even going to be possible to enter NK on any level? Even if you restrict carbs to near zero levels? Should protein be taken to almost zero as well? Which isn’t going to be easy. If even both of those aren’t enough is perhaps high intensity interval based exercise the only thing that’s going to make the tipping point to get the sensitivity up enough to enter NK? I definitely feel better on an Atkins Induction style diet but the BHB just isn’t showing up (I’ve got the Nova Max blood meter) and I’m not really losing any weight and I can’t seem to get my serum glucose below maybe 140 mg/dL. Somehow my liver is finding a way to make glucose even if all I give it are bacon, eggs, and water to satiety, which is still well below the general induction guidelines for “normal” physiology’s.

    • Yes, what you are describing is type II diabetes in the early stages. Remember, protein stimulates insulin, too. So NK requires protein in moderation.

    • greensleeves

      Go to the doctor NOW. You seem diabetic by your own description; you should consider metformin as well as low-carb, Dan Walker. Get it under control aggressively ASAP. Best wishes. 😀

    • Martin Levac

      Dan, I’m no doctor. Not even an expert. I do use my brain though. Sometimes. This is one of those times.

      Assuming you cut carbs to near zero, you’re eliminating the primary cause of hyperglycemia. Assuming you cut protein significantly, you’re eliminating a secondary factor related to insulin. Assuming you begin a weight training program, you’re improving the odds further. Assuming you adopt a proper low-carb diet, a bunch of other factors should be taken care of all at once. If, in spite of your best efforts, hyperglycemia persists, then it’s obvious there’s another secondary factor that still acts. Find a smart doctor.

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  • Frank

    Another great post Peter! Every post I learn a little more that I can apply to daily life.

    Thanks for the insight on the blood ketone levels. I have been using keto – sticks but haven’t been real happy with them. Good time to switch!

    Quick question – For those of us without access to really good testing facilities, is there a way to approximate RQ? I am not a high performance athlete (does being a desk jockey count?) – I just want to try and be the healthiest I can.


    • No, this needs to be accurately measured by someone with the necessary equipment to measure VO2 and VCO2.

  • Leo Sho-silva

    Hi Peter. ..thanks for another intriguing article .I saw in s previous article that your MAF ( Max aerobic function) pre keto heart rate was unusually low at approximately 104bpm for a man your age there a reason for this? Also did your new keto Maf heart bring a big performance jump and did the effort feel the same as 104 ..the implications of this are mind boggling ..your keto maf is equivalent to someone in their late teens or early 20s !!? ..which you could pass for of course :0)

    • This was defined by RQ, which is a bit misleading. I’m not sure I consider that a relevant metric any more. I really only think of HR now as it pertains to power and lactate accumulation.

  • David Winebrenner

    Peter, I have been experimenting with building my aerobic base following Maffetone’s 180 -age tgt to build out mitochondria. I am wondering now if I am missing a huge piece by not looking at ketosis. To stay aerobic for that long a ride, is that due to your huge aerobic base or because of the switch you illustrated in the incredible video presentation regarding the beta gobbledegook in ketosis? Perhaps I have been in the wrong tank and I can’t get to fat usage due to consumption of carbs in moderation/excess ala the Shell oil truck?

    • The issue may be less about the intensity, which is Meffetone’s focus, and more about the fuel source. Diet plays a much bigger role in fuel partitioning than training, though the latter helps.

    • Martin

      Hi. I want to ask, because I am not sure. Is Aerobic base actually Max Fat Zone or Maximal Fat Oxidation?

      Thanks 🙂

      • Different people define differently. Probably no “right” answer. I define as AB as RQ=0.85.

    • Martin

      It is me again 🙂 Answer on my previous question is probably not, but another question. Is aerobic base determined by RQ? RQ above 0.85 is aerobic base?

      Thanks 🙂

  • Alex Li

    Hi Dr. Attia,

    I have been on low carb and high fat for over a year and did NMR Lipidprofile test last year on 8/24/2012 and this year on 8/21/2013. my LDL-P was down from 1255 to 977, HDL-P was up from 26.7 to 31.2 and small LDL-P was down from 451 to 272. These are the good parts.

    The bad parts are my Large VLDL-P was up from 1.1 to 3 and Large HDL-P was down from 4.9 to 3.8. My triglycerides was up from 78 to 100. Most alarming is my Insulin Resistance score was up from 32 to 56. What could go wrong that made me more insulin resistant? Thank you.

  • Wow, you answer all the questions!

  • Heath

    Thanks for the post. I’m curious about your FTP (60m power)? I’ve guessed based on some data you’ve given and if my estimates are correct, then NP of 225w for 6 hours is one hell of a ride.

    If you’re familiar with Andrew Coggan, the ExPhys who wrote the book on training with power, he’s observed that glycogen utilization correlates linearly with TSS/hr. Where TSS is quantified training stress.

    Finally, my question. In the talk you referenced to you showed your VO2Max going from 62ml/kg to 58ml/kg after being in NK for a couple of weeks. Even though your glycogen utilization was very much reduced, I feel like you may’ve understated the reduction of top-end performance that may cause. Specifically, super-threshold efforts would suffer quite a bit. What I’m wondering if whether you would expect the same drop in VO2Max for an individual that was both able to sustain NK and also have fully replenished liver and muscle glycogen going into the test? Presumably, one could achieve the latter with the right timing and the right source of carbohydrate.

    • FTP is about 270-275 watts. (I’m aiming for 300-310 next year, if I can back off swimming a bit — the 2 sports don’t help each other much at all.) I’m very familiar with Coggan’s work and I think his power book is the best I’ve read. I refer to it often. Remember NP is typically higher than avg power (arithmetic), because it aims to mimic lactate bursts by calculating the integral of power output to the 4th power then taking the 4th root (since lactate rises to the 4th power of power output). To your point, I’ve seen the opposite. My 80-90% FTP tolerance is higher now than before and FTP is relatively unchanged.

    • Heath

      I guess I estimated your FTP a bit low. Still, 6 hours at a .8-.85 IF is pretty intense. As for myself, I generally have <50g carbs per day and have a pretty difficult time with intensity above 85% FTP, 5m power also isn't what it used to be, either. It seems that on those few occasions when I do have carbs, it's easier to hit FTP. N=1 though.

      I'm curious to see how this turns out as it's always been the common wisdom that the best diet for aerobic fitness and recovery is one very high in carbs. See the recently published study on the diet of Kenyan runners.

      • Again, I think in me this is part of my background. My background is ultramarathon, so my “sweet spot” has always been just below threshold. My guess is that Kenyan runners could eat poptarts all day and still do well.

  • Mike H

    What’s really funny is I just hiked Mt. of the Holy Cross last weekend, a 14,005′ peak in CO. It’s an 11 mile round trip, with 5,600 ft of net elevation gain. My diet the day of the hike was remarkably similar to yours. I had eggs, bacon, and sausage for breakfast, and on the hike I had about 8oz of salted cashews and 4 oz of sharp cheddar. I had a protein shake made with blueberries, heavy cream and full fat greek yogurt when I got home, and for dinner I had an ungodly amount of chicken with home-made garlic mayo. All in all, probably about 110 g of carbs that day, yet I was 4 lbs lighter the next morning. I normally am still very sensitive to carbs, and will gain weight almost immediately if I go much over 50 g. Yet when I do one of my extreme endurance mountain days, I seem to be able to get away with tons more carbs. I really should start measuring my blood ketones to get a better idea of where I am in ketosis. It might help me zero in on my diet a little better on my lazy days.

  • boy, if that’s sedentary, then I’m a petrified rock. :o)

    • Ha ha. I mean in between bouts of exercise… Living in SoCal (at least where I live), one can’t even walk to the grocery store.

  • GeoC1010

    What are your thoughts regarding a “time window” for optimum carb consumption following a “glycogen deficit” generating period of activity?

    • If you have a glycogen debt, you’re going to prioritize filling it regardless of timing, more or less. The “window” is a largely artificial construct, at least for most folks. It may be more significant for an IR person, where post-exercise IS in increased slightly.

  • Conan

    Dr. Attia,

    Since starting LC have you had the increase in FBG that so many LC folks have. Also, I noticed BCAA’s seem to increase FBG as well. I think the increase is from too much protein and not enough fat?

    The Best

    • Yes. I’ve commented on this before. Hyperlipid has a nice explanation of this on his blog. If BCAA are increasing your FBG… you’re taking too many!

  • Barry

    Firstly, adding my thanks for all the info you share. I’ve seen people suggest that floating in and out of ketosis may leave some people in a constant fog, i.e. semi-adapted. Assume this is not based on anything solid.

    Secondly, regarding “health objectives”, I got a bit excited when I started reading this study on the use of ketone therapy for Alzheimer’s.

    Not so excited when it suggested on page 6 that APOE4 subjects saw little to no advantage from ketosis (I’m E4/E4). Not a very big study, so I guess there’s always hope. For the majority (E3), there seemed to be significant improvement.

    I’m so selfish. Ha.

    • Barry, I think the scientific community is only scratching the surface of what the options exist for AD. I’m very familiar with this study and would like to give you some hope. Look at the table of BHB levels in the subgroups. As far as I’m concerned, at most, the only conclusion I would draw is that the non-4/4 had a slightly higher response than the 4/4 group. If we’re going to treat AD/PD with ketones, we need to get the guns out. Levels of 2-4 mM will be need to be tested to actually start replacing glucose as neuron fuel. These folks were, by my standards, not even in the mildest form of ketosis.

    • Barry

      Thank you for your response, Peter. Much appreciated.

  • Martin

    Peter, do you recommend carb reloading after every glycogen depleting activity? Would it be of any advantage, for performance, health or body composition, not to eat carbs after a high intensity/duration workout and let the glycogen be restored over the course of several days? I presume this would happen even with a very low carb intake via gluconeogenesis. Or is it a bad idea to let the body convert protein into glucose?

    • It depends on the intensity of the workout and a host of other factors. Not a one-size fits all approach.

  • PhilT

    Thanks for the reply, but in a non-US labelling regime it’s more difficult to consider “total carbs” as “Carbohydrate” and “Fibre” are separately determined.

    On the RQ front, is a measurement of O2 and CO2 sufficient, without the flow rate ? Seems to me the ratio of the gases present determines the RQ and the flow is only required to quantify VO2. I’m thinking it may be easier / cheaper to create a hand held RQ monitor like a breathalyser.

  • Ruggiero Guida

    Hi Peter, always incredibly interesting and instructive articles. Thanks for all the time you spend on this.

    Just a note.
    From what I have read so far it seems that exercise determines only 10-15% of your weight/fat percentage/health. You of course exercise much much more than the usual person. It would be interesting to see how your body would react if you stopped most of the exercise you do now. Of course the calories input should be reduced accordingly, but the macro-nutrients ratios should remain the same.
    I have noticed for example that I was leaner when I was exercising harder (P90X for example) and eating much less fat and much more carbs (occasionally pasta, but more vegetables, legumes, soy, oats, etc). Now I eat much more fat (probably 65%) and I exercise much less frequently (usually weights and some squash). I am more muscular on my upper body, but my belly is bigger. You previous article made me think a lot. Maybe i need much more exercise to remove all those fatty acids available in my plasma due to my diet. Anyway I will keep experimenting. On a side note: I am often in Ketosis (normal ketosticks) and my usual blood sugar is less than 5; when i lower carbs i can go less than 4.


    • I agree that exercise plays a smaller role in body weight and adiposity than most people think. When I am not exercising my appetite falls dramatically and, as I alluded to, I actually get lighter, probably due to less inflammation. But for me the emotional joy of exercise outweighs the downside (time, pain, etc.)

    • Nico

      just wondering out loud but if P90x is a cardio exercise versus static weights (n i’m sure that builds your core) even if you’ve reduced calories your waist will increase in size due to a stronger core.
      unless body fat is measured to identify what caused this phenomena despite being NK and reducing calories.

      i feel that being in NK sets the base for the use of fat storage to be burnt during daily caloric requirements and/or exercising. as opposed to spiking insulin and preventing fat storage from being used.

      however it is not the be all end all if you do end up eating 6,000 calories with a sendentry lifestyle…i doubt NK would help.

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  • Martin

    Another great article. These are really helpful.

    Your meal of carbs, if it had a high insulin spike, might qualify as a leptin spiking overfeed used by some body-builders (e.g. John Kiefer’s

  • James

    I have what I hope is a simple question. Like you, the exercise I do is pretty intense, mostly high intensity interval training. I’m also a big fan of NK, throughout my youth and adult life eating this way has delivered the best results for me as well as the best overall feeling of wellness. The challenge I have is, if I follow a diet that keeps me in NK, one where the majority of caloric intake comes from fats such as eggs or meat, my cholesterol (total) soars into the 485 range with my LDL at 343. Everything I know is that this is unhealthy. Back to my “simple” question, is this safe (being at 485)? My goal is very much like yours, to balance my performance AND overall health and wellness.

  • Nan

    Interesting post. My quandary is this: while I’m a fan of NK, if we are to mimic the hunter-gather diet, wouldn’t we want at this time of year normally available carbs like berries, greens, apples, etc?

    • Perhaps, but probably depends on which geography to some extent, along with 7 other things I can’t get into without another 3,000 words.

    • Martin

      The problem is, whatever fruits and vegetables our ancestors could find at this time of the year, they are not available to us any more. The apples we eat today contain much more sugar than anything you could find in the wild.

  • paul helman

    This mishuganeh level of bike riding must create quite a stress induced cortisol output. Have you documented that?
    Very fascinating article. I have been recommending your BLOG to patients frequently to patients over the past two years as a very important resource to correct nutrition. keep up your wonderful work but take up less stressful hoobies. Have you tried free flight model aircarft or home machining?
    Paul HelmanMD.
    Evanston , Illinois

    • Yes, but I have not written about it yet. I’ve barely got one post a month in me. I like your idea of less stressful hobbies…

    • paul helman

      Yes but not neccesarily non stressful . Problem with free flight is that you have to chase the darned things cross country. Maching fine but wear safty glasses and keep fingers away from the spinning headstock.
      Anyhow keep up your very impressive work.

  • Jason

    Nice article Peter. The idea of “glycogen debt” is basically where I ended up in regards to my ketosis. I don’t sweat the numbers anymore. I can “feel” when I get below 0.5 mmol BoHB anyway.

    One interesting thing I was wondering if you noticed, I seem to have developed an intolerance for sugar now (fructose only?). During an ultra I accidentally took in some electrolytes that had some sugar in them and throughout the day I was nauseous. The same thing happened when I tried some sweet potatoes fries with which someone had poured honey and had the same reaction (the occasional 3 or 4 straight sweet potato fries do not give me any problems) . Do you experience some sort of sugar/fructose intolerance ?


    • Jason, VERY funny to hear you say this. I was going to write about this, but the post was already getting too long. On the day before the ride I reported on, I did basically the same thing, except I used much more fruit to replenish glycogen. Even though I actually rode stronger (e.g., higher power numbers, higher avg and max HR, faster speeds), my gut felt horrible by the last 30 miles. Hence, for the following day I said to hell with fructose, I’m going with predominantly glucose to replenish glycogen. In retrospect, this should have been obvious to me for reasons I will write about in the coming months that pertain to how our liver processes fructose and the ATP cost of doing so.

    • Jason

      Excellent, thanks Peter. It is nice to know it was not just me.

      I had a thought that it might have to do with gut bacteria (?). As I understand it Candida comes from an overgrowth of the kind of bacteria that processes sugar. I wonder if prolonged ketosis kills off enough of the sugar processing bacteria that you no longer have enough to handle even a moderate sugar load ?

      I really look forward to what you write about the fructose. I guess I just need to stick with glucose for now. I am still having trouble gauging during a race when I really need to take in glucose. My last 50 mile run I just ran on 200 calories from a quest bar. Felt great all day but could I have been faster taken in glucose ?

      I am currently operating on the assumption that I want to minimize the flux of glucose across the cells that cannot protect themselves via GLUT4/insulin during prolonged exercise. Until I come up with some way of knowing when and how much glucose I can take in without upsetting anyone I will have to continue to minimize it…


  • Eric

    Hi Peter,

    Thanks for your timely post. I’ve been trying LC for awhile and have the same blood meter you do. Unfortunately, I haven’t been successful at getting into deeper levels of Ketosis on a regular basis. I have a food scale at home and at work – my latest attempt was 15 oz of protein food per day (~105 g) and “no visible carb”. I wound up on the bathroom floor with extreme constipation and a suppository 🙂 So the veg. is going back into the diet.

    If my fortunes don’t change I’m going to cut protein to 84g and possible go to two main meals a day. Some people swear by that but I can’t find any data to support meal frequency having an effect on ketosis.

    Keep up the great work – looking forward to the first research paper out of NuSI.

    Best Regards,

    • Eric, you may want to consider adding some caprylic acid in small doses to help with both issues.

    • GeorgeN


      With regards to constipation, you might try adding magnesium to your system. The idea is to start with a low dose (say 200 mg/day) and increase till you reach bowel tolerance. This level is very individual and can be much larger than the 400 mg/day RDA. The body will take what it needs of the Mg and excrete the rest in your bowels. The excreted Mg will absorb water and bulk up your stools. Taking any electrolyte assumes you have normal kidney function. Whatever Mg is absorbed is a good thing, so you kill two birds with one stone. You will also minimize any issues with leg cramps.


  • paul

    The whole point about the religious fervor is spot on. I can understand the reasons for it (we are all making wagers with our health about what the right science is) so there is lots of anxiety tied up with being challenged on our nutritional beliefs. Anyway, the thing I really appreciate about you and Gary Taubes is that it is all about the science.
    Nice post, btw.

    • Thanks, Paul, but I still wish nutrition could be discussed in a manner distinct from debating legalization of abortion of immigration reform.

  • Ron

    Peter, I thought you might be interested in this video of Dr. Mercola and Dr. D’Agostino on Ketogenic Diet. If you haven’t already seen it.

  • Brian

    Dr. Attia, very well written article. I am new to nk, and I haven’t been able to read all of the blogs, yet, but I was under the impression that, when we are in nk, we are using stored fat instead of glycogen stores(or maybe I just misunderstood)?

    • Not necessarily. Depends on the rate at which our muscles demand ATP.

  • Luigi Rocca

    Hello Peter,

    First of all, thank you for writing this blog. While much of the material is over my head, it has given me much food for thought. I have a blood screening every year as part of my membership in a preventative health clinic here in Canada. Long story short, I have decided that at 46 I had to quit smoking (which I did 2 months ago) and I very recently started a low carb diet to kick start fat burning and this has worked. I suspect I am in ketosis because of the results of the ketostyx I’m using but I would like to track other markers and as accurately as possible. How often should I realistically test my blood for things such as triglycerides and cholesterol and should I test my glucose and bhb levels as well? It would be highly motivating to me (much more so than just losing fat) to be able to know that I’m actually getting healthier.


    Luigi Rocca

    • Every 4 to 6 months is probably good, but I realize you may not much say in Canada with health insurance.

  • Pierre

    Peter when you have time could you publish the powerpoint slides from your video highlighted in My Quantified Self, Part I? I find myself opening the video and fast forwarding through to find particular slides.

  • Jane

    Hi Peter,

    Is it possible to get into Nutritional Ketosis (say, above your 1.0 threshhold) while taking a statin drug to lower LDL serum level?

  • Park Firebaugh

    You should charge for these posts. Amazing quality of content. Anyway, I quit racing years ago and consumed massive quantities of horrible carbs at the time because I thought it was required. Since then I do IF and eat very low carb. I started riding again, but I’m not carbing up and only bring water in the bottle. I’ve even done some rides during the fast and there is no distress. I’m not doing time trials and cranking out massive wattages, but I’m not noodling either. After reading Volek/Phinney on low carb performance, I’m convinced it’s possible to function well with fewer carbs than we’ve been led to believe, but I don’t know how well this will work when I pick up intensity. It will be interesting to see how you feel when you’re pumping over 300 watts. Good luck.

    • Thanks, Park. I want to increase FTP to 300 watts over next 2 years.

  • jb

    Awesome training Dr. Attia. Wow! And you look in great shape.
    What’s your time for the 1.5K swim and 43K bike?

    • I’ve never done a Olympic tri, which are close the distances you describe.

  • John H.

    The position/theory that obesity does not cause insulin resistance, but that insulin resistance causes obesity is ludicrous and fallacious with absolutely no supported legitimate empirical, statistical data or studies which have been peer reviewed by qualified professionals and academics. You may mean well but your position is just as valid (and amusing) as the half-wit Neurosurgeon Dr. Eben Alexander who claimed he “saw heaven” when every Neuroscientist and other Neurosurgeons specifically identify why/how his position was equally stupid and utterly false.

    By definition, science requires you LOOK AT FACTS AND DATA and then postulate a theory BASED on the facts and data. You don’t postulate a theory that shoehorn and cobble together cherry picked “facts” and “data” to support it. Please, don’t spread misinformation based upon kneejerk, “anecdotal data” which has all the relevance of 2 guys talking to each other and drinking from gallon jug on a porch.

    • John, I’m pretty sure I’m looking at more data than you are. I’ll give you a pass this time, but watch your tone. You’re crossing a line I have no time for. If you disagree with me, fine, but learn how to do so respectfully or go some place else.

  • Hey Peter,
    I’ve been lifting very heavy weights on NK for about a year thanks to your blog. One thing I noticed in my lifting was that at first it seemed impossible to reach the same level of strength as I had when I had a carbo loaded diet. However, everything seemed to change once I started breathing heavily both during the exertion and inertia parts of the weight lift. This seemed so counter-intuitive to me, but when I tried breathing the “old” way of exhaling just during the exertion, my strength again dropped to pre-NK levels.

    What are your thoughts as to what’s going on here? Does my heavy inhaling and exhaling during the entire lift help me lift aerobically instead of anaerobically? Am I oxidizing fat more than glycogen, thus limiting lactic acid build up, by constantly breathing even with very heavy weight? I typically lift as slow as possible throughout the lift while constantly breathing. Also, I typically lift several sets of 5 reps with 105 lb dumbbells and 225 lb military presses. I’m 5′ 11″, 290 lbs., so I’m not like I’m a bodybuilder. My diet is about 70% fat, 25% protein and 5% carbs. Any confirmation or explanation on my freakish strength since on NK and breathing would be appreciated.

    • I’m not really sure, actually, and don’t have any personal experience with very heavy weight training.

  • Jef

    Dr Attia – Can you comment on Quest bars? They seem to contain a large amount of carbs ( though mostly fiber) as well as sugar alcohols. I’ve been looking for a good bar for some time with no luck, so I often make my own.

    • As you note, most of the carb is soluble fiber. I like consuming them on long rides or as snacks, but I do need to be careful…I can eat them non-stop, if I’m not careful.

  • Mark M

    Dr. Attia, I’m curious to know your thoughts about a correlation between NK and kidney stones; specifically whether you think the scientific literature supports the correlation.

    I found your blog and NuSci through reading G. Taubes work and reading about him. Fascinating stuff.


    • I think there may be some overlap, though I am unaware of any randomized data showing this. It seems like something addressable by electrolyte and mineral supplementation, which will depend on the type of stone being generated.

    • GeorgeN

      Mark, If this is a concern, you may wish to investigate potassium citrate. It is actually the citrate that is beneficial. It appears to be helpful for both calcium oxalate and uric acid stones. There is a prescription med, Urocit-K that you can check out. You can also purchase potassium citrate OTC. The decrease in stone formation with this is fairly dramatic. Look at the referenced studies with Urocit.

    • Mark M

      George N,
      Thanks. My question was more academic than therapeutic. My trainer is skeptical about NK but interested in observing my experience. Risk of stones is his latest bugaboo after seeing me lose fat without a noticeable decrease in energy or performance. I’ve never had a stone.

  • Hi Peter,
    I’ve been on a low carb diet for a while know, but I don’t think I’m in ketosis. I’m really interested in experiencing the brain effect I’ve heard about. What do you recommend is the best way to do so? Currently, I basically eat all vegies except white potatoes (which, sadly, I suspect is what’s standing between me and nutritional ketosis.) Do I need to cut those out? Can I eat salad? Should I invest in a blood ketone meter? I know the choices depend on person, I’m just looking for some guidance or direction.


  • Jamie

    This is fantastic. I love ketosis an it seems to work really well for me after my brain injury, however my sleep tanks after about 2-3 weeks so I want to add some carbs using this formula.

    How would I calculate and measure my power and wattage used in any given exercise, for example some sprinting or other similar types of exercise?

    • Typically bikes and rowing ergometers are the places power is used.

  • John H.

    OK, Peter, please provide the sources, peer reviewed studies and reference material which substantiates your position. I would enjoy reading it and would love to be proven wrong, if they exist. I know what legitimate research looks like and I don’t engage in “fat logic”. Can you provide these citations, source and reference materials please. I have my BS in Chem. E., an MS in Physics and my MBA in Finance and competed in NCAA Division I athletics winning a title in Track & Field. I fully well understand what constitutes a legitimate study and whether it exists. You can email me or post them here. I’ll look forward to it. I deal in facts and data and am very practical and pragmatic. Obesity increasing 300% in 30 years is not caused by genetics or evolution (which would take thousands and or hundreds of thousands of years). Thank you,

    • It seems you think I’m suggesting “genetics or evolution” are driving obesity. Not sure where you get that. Needless to say, this (hopefully) explains your confusion. If you do want to consider the link between OB, IR, and metabolic disease, you may find this interesting:

      Also, consider the clinical resolution of IR s/p R-Y GB which occurs before meaningful weight loss. The is well documented in humans and animal models.

  • Bob

    Kory, I too am a T1 for a relatively short time (2 years). By starting with a low carb diet, then transitioning to a very low carb diet (<30 gms carbs) and now being in NK for about 6 mons I find I have great BG control, rarely use any insulin over my basal dose (heavy resistence training days being the exception) and have no fears of hypos as I can be comfortably in the mid 50's with both brain and body happily living on BHB. Have yet to do a bike ride over 3 hrs without any carb intake but that is in the works for the months ahead. Cheers, Bob

  • KM

    Dr. Attia,
    I appreciate very much your clarity of thought and attention to detail, also your engaging style of writing. Thank you for this blog!

    In #3. of your earlier post “How Can I Lose Weight?” you write: As far as I can tell, there is no reason to limit non-starch vegetables. I probably eat an average of two salads per day.

    Do you count the CHO in non-starch vegs as part of your daily allotment? ( If you’ve answered this already, I apologize for my oversight.) I eat considerably more veg than Dr. Bernstein allows in his 6-12-12 program, but will adjust to “eat to my (new Xtra keto-) meter,” if necessary to achieve DK. I am not diabetic, just find that I thrive on healthful VLC.

    Thanks for your time. Best, KM

    Thank you for your time, Best, KM

    • I do, but it’s quite minimal. I just don’t feel like computing every sub-component of CHO in my diet, so I lump them altogether, though the obviously have very different impacts.

  • Juan Daniel Reich

    Hi Peter,

    Great article again! Have you read Lyle McDonalds work on Ketogenic Diets? I’m on his “Targeted Ketogenic Diet” (3x / week weight training), having pre-workout carbs (2.5g CHO x each working set) 40 mins before.

    Any thoughts on that approach?

    Best regards,


    • No experience with this, so unable to comment.

  • Juan Daniel Reich


    You said you use Abbott Precision Xtra and their Ketone strips. Do you really spend $5 on each test? I looked online and the 10 pack costs $50.

    Any way to testing cheaper (not meaning Ketostiks)?



    • No, I buy either in Canada ($2/strip) or look for other deals.

  • Pete

    Hi Peter, love your blog I think you’re the nearest thing to an “expert” as regards exercise and nutrition esp as it relates to LC.

    In this vein I have a question (sorry!). I have been LC for quite a while and VLC / 24/1 IF’ing for over a year. I’m quite active in a biking/running/walking kind of way.

    I have to be careful when VLC to avoid hypo-glycaemic episodes and need to eat about 120g of protein a day to avoid these and also be careful about eg alcohol as this can be very problematic from this perspective.

    Anyway I have a few last stubborn vanity lbs to lose re: body-fat and decided to up my biking volume to achieve this. I have increased my ride length from 18 mile (avg) to much greater (60-100). Generally I have taken it easier on these longer rides averaging 17-18mph vs 18-20 on the shorter runs (this is a single speed (fixed) bike, not aero ).

    I’m careful re: Fluid and mineral intake but I don’t eat any food during these rides, a 100mile ride takes between 5:40-6hrs.

    After about 4 hrs I begin to “lose the plot” mentally speaking, when I stop (for a comfort break) I tend to have a very noticeable buzzing in my ears and as I go on I tend to feel punch-drunk and lose concentration. However my actual ride performance/power seem OK.

    After such a ride I feel the most profound mental tiredness and I just want to close my eyes and fall asleep.

    Usually after a few hours I tend to perk up (with or without food, but especially with).

    My assumption is that I’m going hypoglycaemic, probably because the intensity/duration is enough to reduce blood glucose beyond my ability to compensate.

    I find that in such situations carbs don’t help much, presumably as they are sucked into muscle? (if otherwise glycogen depleted).

    So I either reduce intensity/duration (probably) to avoid presumed hypoglycaemia. In your opinion can I assume that whilst glycogen depleted in muscle that hypoglycaemic episodes (due exercise intensity/duration) are impossible to counter without (relatively massive) CHO intake as this will be be preferentially taken up by muscle?

    In summary in such circumstances (VLC/low glycogen and not feeding during exercise), exercise intensity/duration should be such to minimise glucose utilisation?

    In all other respects the effect of increased exercise volume on adiposity has been beneficial 😉

    • If you’re not using a very high quality BCAA, I’d recommend it. Mental acuity while exercising may be as much to do with specific amino acids as it is hepatic glucose output, as crazy as that sounds. In other words, a few well-timed BCAA may preserve brain function even as HGO decreases.

  • ER

    Thanks for the thought provoking blog.
    If you have underestimated your glycogen stores, and did not replenish adequately, your insulin should be low. So, your body would give up the lipids from your adipose cells, they go to to your liver to be made into Ketone bodies. At the same time, with insulin low, would your liver not start up gluconeogenesis overnight, to get your blood sugar higher? So that you would get up in the fasted state with increase BHB and normal(not low) blood sugar?

  • Nate

    Wait a minute! Wait just a darn minute! What about the “last chance workout” on the Biggest Loser. Would a contestant be wise to sit out the “last chance workout”? What great drama that would be, great TV! Bob would blow a casket!

    Of course what they probably do is just don’t drink any water that day or night until the weigh-in. Boy that must be good for an inflamed body to be dehydrated.

  • Jeremy MacGray

    Peter, thanks for the info…
    I race mtb ultras and recently did a shorter event of 52 miles here in Steamboat. Was in ketosis for 10 days (av 1.4mM) and did light carb loading two dys out (500g total) mixed with lots of fat, big steak dinner night before. Then I fasted the morning of the event (til 8am). According to my ketostix I was either out of ketosis or almost.
    I raced the whole event on just water, bullion cubes, and BCAAs. This was a particularly hard event (5hr 19min, 6000cal burn, 85-90% of MHR) and I beat my times from years past. Post race my ketone levels were well above 3.0mM.
    It seems that once my body is adapted, when faced with the effort such as the race, it wants to burn fat and will spare the glycogen even with ketone levels reading low.
    Good stuff!

    • Wow, Jeremy. What’s amazing here, if I’m reading this correctly, is that you were only in ketosis for 10 days prior to the race? That’s shocking. 10 days after being in ketosis I could barely walk up a flight of stairs. Obviously, you did a MUCH better job of getting there than I did back in the spring of 2011.

  • Lynn

    Great information, always look forward to your posts and appreciate your time invested on this site.
    A question of less technical detail, is your hummus recipe a closely guarded secret or is there a chance you might share it?

    Kind regards,


    • I’d happily share it Lynn, except no two batches are the same. You see, I grew up in a restaurant and my father is probably the best chef I know. Never used a recipe in his life. So I sort of learned it the “old” way… a touch of this, and pinch of that. Here is the basic philosophy:
      Blend chickpeas in an uber blender (e.g., Vitamix) with enough lemon juice and hot water to keep it mixable. But leave it a touch lumpy. Add salt, pepper, garlic puree or powder, olive oil, cumin, coriander, more lemon juice than you think reasonable, sesame seed paste (tahini). I wish I could explain how I do it, or what taste I’m looking for, but I guess having done it since I was 10 prevents me from explaining it well. Hope this helps.

  • Charlie

    Hi Peter,

    Your blog is amazing. As a low carb eater (for the past 15 to 20 years) and weekend warrior plus (10 hours a week of mountain biking, hiking, yoga and weights), I can’t thank you enough for dedicating your career to this research, and keeping us readers up to date about your self-experimentation.

    In your posts, I dig through your every sentence, looking for morsels.

    During my hike last night, I was fixated on this:

    “Since I’m not a model and nobody cares if my body fat is 7% or 10%, I’m happy to be a little less lean if it gives me the flexibility to increase performance and live a slightly more sane life. At least for now.”

    I think you and I are about the same size. At 5’10”, I pretty much choose my weight between 153 and 159.

    153 is Skeletor – skipped meals, obsessive attention to carbs and protein (29 inch waist, ribs sticking out).

    159 is a lazy upper limit, where I over-eat protein and munch nuts with abandon (31 inch waist).

    156 is a happy place, but still requires serious attention to diet details.

    This bit from the EPIC trial in Europe left me wondering. Waist measurement correlates inversely with mortality.

    On the other hand, I believe a previous publication from the same data set, focused upon BMI, showed the low end of the scale turning J-shaped. Among male non-smokers with extremely low BMI (can’t seem to find that right now) , extremely low BMI was associated with an increased risk of early death in men (but not in women, interestingly). But we are talking super-low BMI – 19, 20, 21 range. I suspect they suffered undocumented comorbidities.

    Is it possible Skeletor is a healthier weight (and worth the craziness)? Can you propose a possible mechanism arguing one way or the other?

    • Charlie, these waist/BMI papers don’t apply to someone like you. The investigators, in their defense, are trying to find some simple yardstick to measure risk by. But you’re already way out of their target zone. Besides, there are FAR better ways to predict risk if you have access to lab testing. E.g., CRP, LDL-P, TG, OGTT.

  • Peter

    Peter: I always assume that alcohol (wine) goes into the carb percentage of calories. I am generally about 65%-75% of calories from fat, with the remainder evenly divided between protein and carb – and the carbs include a glass or two of wine about four or five days a week. Do you agree wine would go into the carb percentage?

    • If you can isolate them. A glass of dry red wine (my choice of EtOH) is only about 4% sugar by weight, so very little. The actual source of calories is the alcohol itself. It’s probably only the case in beer and sugary-drinks that the CHO content starts to “count.”

  • John Myers

    Great article. I’m so glad I don’t have to fear the chickpeas (in moderation I suppose). Thanks Peter.

  • Charlie

    Thanks for answering, Peter. I think I’ll stay away from the Skeletor look for a while. It doesn’t seem worth the trouble.

    Keep up the great work!

  • Brock Snyder

    As always, very thorough. I’ve lost to date 100 lbs on the LC – VLC way of eating, over about three years. I stumbled through it painfully without really knowing what I was doing. I’ve read and read and read. I mange to get lucky and lose weight. My wife and others who are very interested in becoming “more-less-obese” struggle understanding any of it and my wife can’t seem to lose anything. She’s been on nothing but meat and fat for two weeks now. Others I work with, as is always the case in my experience, want/need to lose weight, but don’t read much and can’t follow these kcals, ncal and %cho (oh my!).
    My question is this: Where’s the “for dummies” version? Most people I know don’t read Med Journals or sentences with formulas that contain numbers AND letters. Is there a guide for the fat and simple? And what happens when their cells are insulin resistant? (Did I say that right?)
    Your work and attention to this problem captured my attention and I think your work may make the nutritional and medical society take note of the wrong information out there. Keep up the great work. It sucks being obese and not being able to do anything about it because of lack of effective information.

    • Good question. I don’t really know. My fear with the “for dummies” stuff is that it (obviously) simplifies things. Sometimes this is very good, but other times it can be counter-productive. I think great teaching requires the ability to know when to go simple vs. complex.

    • Martin

      How about “The New Atkins for New You” by Westman, Phinney and Volek?

  • PhilipL

    Re. restricting protein intake to attain NK – Am I right to assume that anything above 120g/day would cause the body to manufacture glucose through gluconeogenesis, thus inhibiting production of ketones?
    The `rule of thumb’ for strength training seems to be around 2g/kg a day of protein for building muscle, so adopting that for anyone weighing more than 60 kg would seem to rule out NK.

    • It would be tough to stay in NK while consistently consuming over 120 gm/day of protein, but as this post suggests, context is everything.

  • Di

    This is a timely post. I committed to low-carb about three weeks ago and have noticed a big difference–at age 36, I now know that what used to work doesn’t work any more (I have been eating low-glycemic over the past year). I’ve dropped six pounds and had no noticeable bloating during PMS (I know–fun topic–but the bloating has been getting so bad that I looked like I was pregnant). The only reason I knew I was retaining water was because my ankles were very slightly swollen–a major improvement. I do not meet the criteria for metabolic syndrome–all levels are good, I’m just heavy (187).

    I’ve been laboring over tonight–my friends and are doing an urban ride and we’re meeting at a brewery that only serves pizza–and damn good pizza. I don’t think they serve whole wheat or even gluten-free, so I think the crust will be the highest in carbs it can. It’s a 10-inch pizza. At this point, I think I’m just going to load it up with protein and fat and enjoy. After all, it’s a rare occurrence, and rarely do I not have the option for a low-carb alternative when I go out to eat. My only worry is that we’re tackling a grueling trail for tomorrow’s mountain bike ride, and I suspect that I would do much better if I didn’t have the pizza (okay, AND the IPA). I fully-expect to be out of ketosis.

    My question is, *if* I’m keto-adapted, so this could be hypothetical given my short time with low-carb, does that require another induction phase, or does the body bounce back into it within a couple of days of a cheat meal. Do people who do one cheat meal per week (*not* what I want to do) after induction ever become keto-adapted?

    • Probably depends on the nature of the meal and the time you’d previously been in ketosis.

    • Di

      I had the pizza, but then we did our pub crawl the next day and I singlehandedly kept the IPA industry in business. The next day, I had trace amounts of ketones in my urine and it stayed that way until this past Friday when the ketone strip turned a couple of shades darker, which made me happy because I had a 37-mile mountain bike ride yesterday (Saturday). I then had three pints of IPA and a nine-inch pepperoni pizza. This morning, my ketone strip was between the lowest two positive shades, which I’m taking as a good thing, but I’m also thinking tomorrow’s will give a fuller picture.

      Regarding the ride, I made it through on 36 almonds while my friends were stuffing down Cliff bars and PB&J sandwiches. I did have great difficulties on the final multi-mile climb, but it was because I ran out of water earlier–easy problem to solve. I guess you can say that I had a water-bonk. I bonked last year, so I’m well aware of what it feels like to need more carbs. That absolutely was not an issue this year. For this reason, I am sold on low-carb for endurance sports. Also, the most I’ve mountain biked this year is 15 miles. To take on a 40-mile ride like I did yesterday is gutsy, but I firmly believe the low carb diet allowed me to tap into my reserves to keep going. Post-ride: no headaches, no lethargy, no physical heaviness. I was bright, happy, and while I certainly felt like I had completed a hard effort, I generally felt awesome.

      I think what might help is that when I do eat something higher in carbs, I try to preemptively counteract it with protein and fat. I guess you could say that I’m trained to do this because I was on a low-glycemic diet prior to going low carb.

      I just wanted to report back since this seems to provide a bit of an answer to my original question, and maybe it will help someone else. 🙂

  • Kathy

    Hi Peter,
    Thanks for a great website. I have been reading-up on your cholesterol series–as a part of that I jumped over to lecturepad to check out some of the other info on cholesterol etc. One of Dr. Dayspring’s case studies (lipidaholics-case#291) discussed how pratictioners see a large number of “low-carbers and paleo” patients who see a worsening of their lipid profile–alarmingly–the increase in LDL particle #. Have you seen this case presentation? do you have any comments about it?
    I have been doing a low-carb to very low carb, high fat diet for the past few years –primarily to stay weight stable and keep insulin levels low as I am IR(hx of pcos)—this case study really alarmed me in that it was the first time that I heard of some of the possible down sides to doing this type of regime. I know that this particular patient got things back under control by lowering saturated fats and adding some carbs back to her diet–while still staying low carb. Any comments would be greatly appreciated.

    • Yes, I reviewed it as Dr. Dayspring wrote it. I’ll address in Part X of my series when I get a chance to write it.

  • Ripa

    Hi Peter,
    I have been in a LCHF from 2008 and still going strong. Diet has suited well for my strength training workouts and have made some personal records. Now I started hockey training which is much intensive (my average pulse for one hour game is around 160 per minute), What should I eat before hockey training? Should I eat/load carbs right before training or only after? Or does carbs before training just disturb fat burning “engine”?


    • You will likely require CHO to maximize your performance in a game like hockey, especially at the intensity you describe.

  • Norm

    Hi Peter,

    Thanks for another great article.
    What is your take on cortisol in terms of weight gain and plateau as compared to insulin?
    How far is it true that being in ketosis over a long period of time can cause the body to increase cortisol levels that can cause plateau or weight gain?

    • Increased cortisol can certainly reverse or retard fat loss, though I’m not impressed with evidence implicating a low carb or KD. But if one is worried about it, it’s easy to test: change diet and observe change in fat and cortisol level.

  • Jon

    Appreciate your website! =)

    I’m currently following a routine roughly 3x per week consisting of alternating workouts:

    Workout A
    – Powerlift Squat
    – Olympic Clean and Jerk
    – Powerlift Bench Press
    – Dumbbell Row

    Workout B
    – Powerlift Deadlift
    – Olympic Snatch
    – Dumbbell Bench Press
    – Weighted Pull Up

    Each exercise is performed for 3 sets of 5 reps. For this program, I’ve been trying to remain in ketosis with starchy carbohydrates only after exercising. It’s awesome that right as I started this program, I came across your website. It’s been an invaluable resource!

    My question for you is, how many carbs do you think would be safe to consume after each workout? Right now, I shoot for around 100 g, but I think I’m doing as you say…overestimating how much glycogen I actually burn during workouts.

    Coincidentally, I have had trouble keeping blood ketone levels up. Thanks in advance!

    • Jon, I can’t estimate just from reading this.

    • Jon

      No worries. I think my best bet would be to just find a good amount of carbs through trial and error using ketostix as a rough guide…and knowing their limitations.

      Do you have an article on your site which compares CKD- vs. TKD-type approaches? If no article, do you know of any good studies? I’ve been searching, but can’t find any that compare physical performance between the two (and also vs. SKD).

  • Ade

    Peter hi been attempting a higher fat diet that is lower in carb since I came across your ted talk and your blog. Not the easiest thing to do in Dubai and now Nigeria. It has also gotten me into doing lot more nutrition research than I’d have preferred but one must learn. My body type and weight gain story is similar to yours though I exercise ONLY lightly these days but the trend (weight) has been steadily up over the last decade as I’ve grown older (now 37). I’ve lost 10 lb or so in the last couple of months. dropping to just under 200lb for the first time in 6 years or so. Through the research i’ve gotten very curious about which oils are better than others for frying. I’ve been frying my (and my kids) eggs in butter but thinking about trying palm oil or coconut oil. I’ve not found a great source to help parse the “oils” world and the pros and cons. Can you suggest a resource for this if you’ve looked at it? Or share your thoughts. Best.

    • Best for high temp frying is pure SFA. Coconut or palm best.

  • Lau

    Hi Peter,

    Thank you for your great efforts!

    My question is somewhat in line with this entry. I was wondering, can ketosis and (hereditary) kidney disease co-exist? My education (medicine) is a lie, my doctor has no clue, and dieticians… well, you know. And I’ve been reading as much as I can recently, but this topic is skipped everywhere (or buried under the ketosis is bad for your (healthy) kidneys myth). Lately I’ve just been easing out the carbs after two failed attempts to maintain ketosis.


    • Not sure which kidney condition, but I guess the question is what additional demands does a KD place on a less functional kidney? KD does not require additional protein, so I’m not sure the concern.

    • Lau

      Thank you for your reply! The condition is Alport Syndrome.

      I must admit, I was a bit skeptic when I heard about KD. I well understood the benefits, but I could not see how it could work for me personally. As you know, low protein consumption is recommended for kidney disease, as (some?) amino acids increase the GFR. I was actually delighted when I saw the ratio’s for KD, although it still is a little too much, if you compare it with the recommended 0,8 grams/kilogram body weight.

      However, what actually worries me is the combination of the ketone bodies, which as far as my knowledge goes increase GFR, the -too high still- protein consumption, which increase GFR and the heavy dietary electrolyte load.

      I am afraid the load on my kidneys will be to much. My attempts failed due to extreme fatigue (which could be normal in transitional state). The reason I decided to quit was that the foam layer on my urine (my subjective way of measuring my kidney function, heh) was getting too big.

      I was wondering what your thoughts on kidney load where!


  • Paul Arena

    Hey Peter,
    I just scheduled a doctors visit for my mother who is having, what I think is, terrible bouts of reactive or regular hypoglycemia during the night or mid morning after fasting for a while. It has gotten more frequent since trying to adopt a low carb lifestyle. Myself and my Dad have responded well to the Keto diet and we feel great. What types of tests should we request from the Dr.? I say glucose tolerance test and insulin blood levels. My thought is that she can’t access her fat stores. When fasting overnight she gets the epinephrine surge and then gets the symptoms. Any thoughts would be awesome.
    Keep up the great blog posts.

    • Her doctor should probably look at other endocrine systems, including adrenal axis, and even measure glucagon, along with OGTT, etc.

  • Kath

    Hi Peter, Such a timely article for me, thank you. I’m 7 days into ‘low carbing’ and still very much a newbie but excited about the possibilities. I’m hoping that I may be one of the lucky ones who can use fat as the primary energy source during endurance cycling. I currently do 200 miles of cycling a week, 100 miles of commuting ( low level stuff) and 100 miles with my cycling club. On the club ride this week I completed the distance, however was very slow and got dropped out the back. I accept that as this was my first week of low carb my body is still learning to use fat for energy.

    Question is, how long might this take, or is that just impossible to tell. Second question, if I read your article correctly then is it ok to eat a higher carb amount on big club ride days, especially just after the ride. Third question, is oatmeal ok as a carb source just after or during a ride ( perhaps in the form of a flapjack). Apologies for so many questions, just keen to do this right. Thanks so much for reading.

    • Should be all addressed in other questions/comments/posts.

    • GeorgeN


      Basically, it sucks for everybody when they are first getting adapted. You just need to accept this. The fact that you can finish a 100 mile ride with your club during adaptation is actually quite remarkable. I’d guess it’ll take you two – three weeks to get adapted, though there may be ongoing adaptation after this. My suggestion is that you do not “cheat” or play the games that Peter is playing with carbs until you’ve been fully adapted for a while, otherwise you may just delay the process.

    • Michelle

      I am primarily an endurance focused athlete and the transition to low carb, which I began back in June of 2013, has been very difficult for me in terms of running and other aerobic performance. However, I am stubborn, and because I was seeing so many other benefits, I continued to struggle. I took to heart all the advice on the blog, monitoring protein intake, increasing salt intake, introducing BCAAs, but nothing seemed to make a significant difference. Recently I noticed that I am losing more hair than usual, and based on my own research, this is not unusual on any diet regimen, particularly low carb, and generally corrects itself once your weight stabilizes, when taking into account hair growth cycles. Not willing to wait and see, I began supplementing with a “hair, skin, nails” formula, which is primarily B vitamins and C, not coincidentally, I think, your classic “stress” vitamins. I saw a noticeable improvement within a few days. I think the doctor could comment better than I could theorize, as to all the reasons why this may be true, but I think it is worth a try, and, in any event, would not be harmful.

  • Q

    Have you ever considered taking metformin before a cheat meal to maintain ketosis?

  • Jason

    Hello Peter,

    Thanks for the great blog. This is fantastic information.
    I have been looking through the blogposts for an answer but have yet to find.
    When do you supplement? All in the morning or split through the day?


  • kasper

    Hi Peter,
    I’m very much in doubt as to which diet is healthier LCHF or IF ie. one meal every 24h?
    I’m not trying to loose weight or run a marathon I just want to be as healthy as possible
    thanks for a great site!

    • Andre

      some studies suggest that benefits of NK and IF are overlapping but not the same, hence you probably have to do both. maybe you could just do one and supplement some stuff like resveratrol if you are after some specific gene expressions.

      however – why not have both? in practice, anyone doing LCHF should automatically be fasted regularly (less hunger) and hence reap both benefits partially.
      I do (without any difficulty) 24h fasts at least weekly, most days I do 18/6 (=2 meals within 8h, usually lunch and early dinner).

      I do IF as well to compensate that I cannot work out as much as I would like (5x)

      maybe get your inflammation markers checked as a means to control your lifestlye, however all I did came down with non measurable values.

      get you genes tested if you are apoe e4 with one or two copies I belive you have to

  • Rob Weiner

    Thank you Dr. Attia for another great post. I know that you are big into objective numbers in your n=1 study, but my question is this: what –if anything– do you notice on a more subjective level when you slip out of NK? Does the birthday cake make you feel loagy? achy? sleepy? no different? How long does it take you to recover? Do you track your subjective emotional, intellectual and physical energy levels daily and if so what have you noticed in relation to the lab #’s and diet.

    Thanks again for all the time and effort you put into this blog. It has been of immense value to me as I conduct my own n=1 experiments.


    • Quite a bit, Rob. I feel pretty lousy when I fall hard out of NK, usually for a few hours, but it depends on the demands I put on myself, too. For example, if I wake up with BHB of 0.4 and I’m about to hop on my bike for a long ride, the first 2 hours will hurt until my liver starts making enough. I don’t track emotional, though I think I have too many confounders.

    • Richard S.


      As another data point, I feel like dirt when I fall out of NK.

      I lost 35 pounds on a LCHF diet, and now have a BMI under 25. This summer I decided to allow a few more carbs in my diet, but I did it the wrong way. Instead of a sweet potato or a slice of multi-grain bread, I’d have a few light beers, a few slices of pizza, or some cheese and crackers (which those around me were having).

      The result was my insulin resistance returned with a vengeance. I was back on the energy roller coaster, and the lows were murder. In the middle of the afternoon, or in the evening an hour after supper, my energy would hit the floor and I’d want to crawl off for a nap. That didn’t happen when I was in NK. I’d also run out of gas early on my hard (relatively) hour-long bike rides.

      And the cravings came back — especially in the evenings, as my blood sugar dropped and my body was telling me to eat carbs to bring it back up.

      Volek says that getting and staying in NK is like climbing a big sand dune — much easier to stay on top, than to keep sliding down and climbing back up. I have give a big “Amen” to that.

  • g

    Just had a brief read/musing about the effects of sirs on exercise physiology. Thank you for mentioning it, any particular sources that you might recommend?

    • Everything I learned about SIRS I learned during 5 years of critical care medicine. The classic Marino text was very helpful, but no mention of exercise, of course, just sepsis, burns, cardiogenic shock, etc.

  • Mark M

    I am off to buy the September issue of Scientific American in the morning. Looking forward to reading about the work of you, Gary Taubes and NuSi.

  • MMC

    Well after years of reading all a lot of nutritional studies and listening to all different experts talk from Dr. Ornish, Dr. Furhman, Dr. Willet and of course your work Peter (which finally put all the pieces together) I have developed framework for nutrition which I present here:

    What did are ancestors eat and can that help us develop the an optimal healthy diet?

    What did your ancestor’s truly eat? Everything they could. Yes this means grains and beans when available (not year round like today), plus fruits, vegetables, meat, eggs, insects, fish, and rotting/fermented foods. They were constantly battling starvation and had to make use of all sources of food available to survive. This is key, most of the time our ancestors would be in a starvation/survival/fat burning mode. This survival mode is the healthiest state to be in. Every animal lives longer on a low calorie diet or by someway tricking the body to think it is in a low calorie state. The key for optimal health is being in this survival/fat burning mode while at the same time maximizing nutrient intake. Okay so let me explain why I agree that a high fat low carb diet is optimal.

    What our ancestor’s ate grain and beans?

    Yes they ate grains and beans, but the grains looked more like teft and for beans look at the wild ancestor of soybeans it doesn’t have the nice plump seeds of todays varieties. Grains were a lot lower in carbohydrates and higher in protein when our ancestors lived. They didn’t have the plump wheat, corn, and rice of today. Even vegetables we think of today as low in carbohydrates (broccoli, kale, and spinach) are nothing like what our ancestors would have come across. Fruits are the same, sweet apple varieties are a modern invention along with most sweet fruits. Crab apples are a lot closer to what our ancestors would have come across. Todays plants have been breed for higher yields and sweeter tastes. Lets face it todays food tastes a lot better then the tough, bitter, small wild plants of our ancestors. This increase in carbohydrates in plant foods available to us today is a major reason why even eating a whole plant based diet today, I would argue, won’t give you optimal health unless you eat a low fat, calorie restricted diet as well and hopefully you will see why by the end of this post.

    Why are carbohydrates the important nutrient to a healthy diet?

    To me a healthy diet today its all about insulin control and the way to control that is through carbohydrate manipulation. When we eat a lot of carbohydrates, insulin levels go up, fat burning goes down and our metabolism switches form starvation mode to reproduction/fat storing mode. It makes evolutionary sense that carbs would be our bodies fuel of choice, it can’t be stored, produces a lot of energy and because in nature if you have access to them it means food was abundant and it time to put on weight and reproduce. Yes I think we evolved to get fat when a lot of carbohydrate dense food was abundant. This is not a healthy state to be in and is the cause of your current health problems. We are eating a diet that is meant for us to quickly reproduce and quickly get out of the way of the generations to come.

    Why would our ancestors burn fat, their primary storage fuel first, when carbs were plentiful?

    It wouldn’t make any sense form an energy stand point. It is a lot better strategy to burn carbohydrates and store any extra calories as fat from any source (carbs, proteins, fats) for lean times, which was most of the time. We did not evolve to burn carbohydrates as our primary fuel source all the time. We did not evolve to produce that much insulin or to be efficient at metabolizing fat when on a diet rich in carbohydrates. Our bodies have evolved to store calories under these conditions. Our bodies are able to run on a high carbohydrate diet, but to do this for optimal health we then we must limit our fat and stay in starvation mode through reduced calories. This maintains us in the starvation state, our bodies are burning all the calories we are consuming and the little bit of fat metabolism that is still activated is able to deal with the small amount of fat in our diet without negative consequences.

    We are adapted however to get our nutrients through plant I would argue. Lets face it our distant ancestors ate a lot of plants and our body physiology is meant to eat a diet high in plants. There are far more protective compounds in plants than animals. The one thing I have not seen supported in the scientific literature but wonder, is if our bodies are better at regulating essential nutrients through plant food than animals foods. Iron comes to mind. If you have high iron levels your body can absorb almost no iron from plant foods or if you are deficient it can absorb almost as much as meat. Another one is beta carotene, our body will turn it into vitamin A if needed, but if you have enough vitamin A it will keep it as beta carotene/host of other carotenoids that are beneficial to health. However Vitamin A in excess is very hard on the body. Another strong piece of evidence for our ancestors eating a diet high in plant food is our inability to produce vitamin C which almost exclusively comes from plants. Only exception I can think of is the narwhal whale.

    There are few exceptions of nutrients that are better obtained from animals that show meat is an important part of our ancestors diet. Omega 3 is one. Humans are not great at turning plant based Omega 3s into biologically active forms and hence must have come from somewhere. I conclude that eating insects, wild animals, and sea food would have supplied enough omega 3 that there was no evolutionary advantage to developing the ability to convert the inactive form found in plants into biologically active forms our bodies require at faster rates. This supports humans eating a diet that included meat. We also didn’t eat as much omega 6 (grains) which blocks our ability to form the biologically active forms of omega 3. There are other high energy molecules that I think improve human health that are only found in animals as well.

    Okay what can we take from the above to develop an optimal diet today?

    I think the goal of a diet should be to maintain your body in the survival/starvation/fat burning mode. If this is true what is the best way to accomplish this goal? Well the easiest way to stay in the starvation mode is to starve yourself. I think everyone would agree that this isn’t sustainable or desirable, yet it is what people on low calorie diets do. It is also what you would have to do on a low fat diet to make sure you burn all the carbohydrates you consume to prevent excess getting turned into fat. The other option is to not eat carbohydrates but instead fat (thank you Peter for introducing this to me!). This tricks are body into thinking we are in a starvation situation as there are no carbohydrates to burn. In this state our bodies really kick in to survival mode and are able to deal with a lot of molecules that have negative health consequences under a high carbohydrate diet, i.e. cholesterol. The wonderful part is we don’t have to starve ourselves!

    Okay so we want to eat a high fat low carbohydrate diet what should we eat?

    Peter you do a great job of explaining this and have a far better grasp on it than I currently do so I’m only going to say a little bit of what I think that I have yet to come across.

    I would argue that it is important to try and eat nutrient dense animal foods. Eat organ meats, marrow and other parts of the animal that have a lot of nutrients.

    I would still argue that we should really emphasize plants foods (ie nuts, beans, veggies, fruits and possible a tiny bit of grain now and then. Yes I love sushi too!) and try to maximize the amount we eat to get all the health benefits from them. Our goal in selecting plant foods should be to eat foods that are very nutrient dense and have a very low glycemic index/load. Goal is to keep are carbs and therefore insulin in that target range that allows most of your metabolic needs to come from fat but still gives us the phytonutrients only contained in plants. Peter’s finding of being able to eat a high amount of carbs after intense exercise could be used to be to eat more fruits and other high glycemic foods that have a lot of health benefits.

    In conclusion I feel we are trying to mimic our ancestors diet however, with todays abundance of food we have to opposite problem of our ancestors in that we are trying to figure out how to stay in a starvation/ fat burning mode that their environment naturally forced them to be in. They were able to eat everything and anything they could but I feel that data supports that they just didm’t have access to the high glycemic foods (or not for long periods of time) of today so it was not a problem for them. Today we have to use modern nutritional science to figure out the best, most sustainable way to keep ourselves in this survival mode while we maximize the nutritional content of our diet.

    Okay I wish I could have posted references to all this but I don’t have time/will power. Also I didn’t know where else to put this and I think it kind of fits in because it kind of shows why we can’t have ketones and carbohydrates, unless we are of course in a glycogen deficit. Sorry for the ramble hopefully someone finds this useful and possible use it as a way to show that both high fat and high carbohydrate diets are healthy, it just depends with one you prefer.

    • Greatly appreciated. Thanks for putting your thoughts together. I’m sure others will have suggestions, also.

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  • g

    I found some interesting studies via google scholar. Likely I will get the idea between unlocking the pay wall, the Marino text you mentioned and some endless reference reading. I wanted to mention that I am having great results with nk and my own training. Thank you

  • Esther Kwon

    Dr. Attia, I’m curious to know your new findings on the connection between diabetes and obesity after seeing your TED talk this summer. Anywhere I can find more information on this?

    • NuSI is working hard to fund scientists to find these answers…but doing great science takes time. Stay tuned.

  • Yossi Mandel

    Dr. Attia, I’m trying to understand the relationship between a bomb calorimeter and energy produced in the body as part of the “a calorie is/isn’t a calorie” science discussion. Since our body doesn’t produce energy through instant combustion, rather through a slower change of reactions that may end in combustion, shouldn’t we say that at best a calorimeter measures the potential for energy release within the body? I mean this question from the point of view of the calorie is calorie camp. Since there are so many steps before energy release in the body, meaning that the energy may never be released (say, undigested food passed as waste), there is caloric potential, but I can’t figure out how putting the food in the mouth is assumed to be equal to putting it in a calorimeter.

    If it only measures potential, then all we know from a calorimeter is the maximum energy possible to extract from this food. To find out how much is actually used as energy, we would need some sort of tracer in the body along with the food to truly measure the food’s impact, right? Until then we’re just guessing based on proxies and self-experimentation. Again, according to the calorie is calorie camp.

    I am happily drowning in the research but some reassurance that I’m barking up the right tree would be helpful. Thank you!

    1980: Earliest note I see of imbalance between calorimeter and human energy expenditure
    Energy balance in man measured by direct and indirect calorimetry

    1988: Earliest questioning I see of calorimeter validity for human energy expenditure
    Theory and validity of indirect calorimetry during net lipid synthesis.

    I see that 1988 paper is cited by Dr. Kevin Hall, who you’ve mentioned:

    Recent research by USDA that calls calorie count for pistachios and almonds into question:

    • A bomb calorimeter measures total (potential) energy contained with the C-H and C-C bonds of organic matter. But there are several fates for that energy when we eat it. Under “normal” conditions, most of that potential energy has one of two fats: 1) “kinetic” energy — i.e., gets turned into ATP by the body, and 2) more “potential” energy, as stored energy in the body (fat, glycogen, and even muscle if you think about it). Some may leave the body (e.g., stool, urine), which is relatively straightforward to check, but rarely amounts to much outside of massive nitrogen losses (urine) or steatorrhea (stool).

    • Yossi Mandel

      Are there not other uses of those bonds in the body?

      Gut microbes take their share. Tissue repair, cellular functions, secretions. Shouldn’t that affect calorie count by detracting from ATP and fat storage?

      • Absolutely, but those take place within the body, which we define as a closed system. Tissue repair and the other things you list still require converting the potential energy of C-C and C-H bonds into other sources of energy. This all requires ATP. So while a bacteria may use up some of this energy doesn’t change the fact that it’s being used up inside the system. E_in = E_out + E_stored. (E_out includes “work” and loss)

    • Yossi Mandel

      Okay, thanks for the clarity. The calorie is calorie camp would still have to explain the more recent research that measured the inconsistency in counting calories.

      This 1990 study shows that doubly labelled water measured energy expenditure as 15% less than room and other calorimetry (sample size 4):
      Comparison of doubly labeled water, intake-balance, and direct- and indirect-calorimetry methods for measuring energy expenditure in adult men

      This recommendation to the European Union suggests calories off by up to 25% (by Geoffrey Livesey, an author of the 1988 study, who should probably be considered the archetype of the calorie is calorie camp):

      I see other recommendations such as that USDA one I posted that calorie count may be off by as much as 25%.

      So that even according to the calorie is calorie camp, calorie count should be reduced by 15%-25% after adding up food calories for the day. And even that is just a guess because energy use can only begin after digestion, so at the very least stool would have to be checked. Basically, a more precise presentation of their argument might be “a calorie whose consumption is measured by doubly-labelled water is a calorie” or “we estimate that a calorie as defined by Atwater reduced by 15%-25% is a calorie.”

      Not that it matters practically, but helpful academically to me to know that they don’t necessarily understand their own position.

  • leslie

    If I had a dollar for every time someone said carbs on this comment thread I’d be rich 🙂

    I prefer replacing my glycogen stores with protein. I crave it (and not bagels) after a workout. I do have to be careful though as it would be easy to eat two pounds of brisket instead of 8 ozs after a long bike ride and throw myself out of ketosis. A bonus is that the next day after a hard workout and a modest refueling with protein I am in the ephoric range of deep ketosis.

    I love going here to learn as you have indepth articles on intense exercise (and so many more keto topics) and the ketogenic diet. I see this no where else but in the books of Phinney and Volek. So, thank you, thank you!

  • Raymund Edwards

    Peter , Do you think this paper could suggest that low amounts of things with fructose , like small amounts of fruit eg berries could be a superior carb on a keto diet ? I am keeping net carbs around 20 to 30 grams , but feel good when they include some berries ! I feel stronger ( more repetitions in say chin-ups ) and have more endurance in things like running.

    if fructose does not spike insulin as much and can cause a three fold increase in glycogen synthesis would it be an advantageous carb on low carb and keto diets?

    This caught my eye from this paper

    Fructose, through its metabolite fructose-1-P, has been shown to have catalytic effects on hepatic glucose metabolism by increasing glucokinase activity(,3). This mechanism has been shown to relate to an approximately 30 % decrease in hepatic glucose production under hyperglycaemic conditions in type 2 diabetic subjects(,3) and an approximately 3-fold increase in glycogen synthesis by 13C NMR spectroscopy under euglycaemic conditions in non-diabetic subjects

  • Robbie

    Why do we need pre-event meals (morning of) and why does their composition matter? I am reading your post with the selfish question of what to eat the morning of the Chicago Marathon. If a) my diet leading up to the event has been sound from a NK standpoint, b) my body will largely be fuelled by my fat stores during the race, and c) carbs will be provided by sucking back UCAN pre-race, is there any substantive reason to choose scrambled eggs over (sugar free) ice cream at 5am? Or, is there a preparation for this extreme stress that the morning meal assists with – while preserving the benefits of NK?

    • My general “rule of thumb” is to consume nothing before rides of <50 miles (which probably translates to a run of 18 miles or so), provided BHB levels are over 1, and preferably 2 mM in the am. BUT, and this is the caveat, it is highly dependent on the output. I've done VERY easy 80 miles on nothing but water with no meal since 7 pm the night before. But if I'm going to burn some matches, I like to get some protein and fat on my stomach, and I need glycogen replacement, starting around hour 2. In the end, this is something to figure out personally during training. I love scrambled eggs cooked in coconut oil because it's very ketogenic. But so is keto-ice cream. I just don't crave sweet stuff in the morning, but I do crave salt. Chicago is at least a month away, right, so I think you can try out a few different pre-race meals over runs > 10 km.

  • Martin

    Many of the questions and answers here are very insightful, keep it up! Your work is greatly appreciated and is already improving the lives of many people, I am absolutely sure of that.

    You wrote this:

    “Just read a review article on this recently. No evidence post-lift CHO plays any role in muscle synthesis. Protein is sufficient.”

    I find that VERY interesting. I thought insulin was one of the most important anabolic hormones. I was actually going to ask how to use the anabolic effects of insulin despite a low carb diet before I read that comment. Does that mean that the only advantage of carbs is that you can exhaust a muscle to a higher degree? Does the anabolic effect max out on low insulin levels?

    I would be interested in that article if you still have the link!

  • Indy M

    Reading this :

    “A CRITIC AT LARGEMAN AND SUPERMANIn athletic competitions, what qualifies as a sporting chance?

    I thought it was topical, especially where he talks about competitive Biking.

    In NK for 8+ months now, I often wish I could monitor, manage and manipulate, in real time, the factors, as Malcolm talks about, that go into an endurance event(running for me). This may be a few years away.

  • Chris

    Peter – any chance you will share that hummus recipe you mentioned ?

  • Conan

    Dr.Attia, I was curious your thoughts on why you have been able to escape the negative effects on your labs from marathon style exercise that others like Ben Greenfeild had. Do you attribute it to ketosis only, or is there something else I am missing. If so that could drastically change the workout protocol for most of us.

    The Best

    • I think Ben is doing a remarkable job, certainly based on the long conversation I had with him on Sunday after his race. There will be a few things we tweak going into Hawaii, but overall, and certainly for the first 8 hours of that race, he was on fire. I’ve had many missteps, myself, remember. This is new territory, and progress is highly empirical.

  • Patrick R.

    Peter, question for you:

    I currently stay in ketosis for about 2 months, and then cycle back out for a month.

    While I find ketosis to be my preferred state, both mentally and physically as far as my running and biking, the reason that I cycle out is because I have seen a fair amount of other N=1 experiments (mostly paleo VLC forums) where thyroid issues have arisen from longer term VLC diets.

    I am aware you have been pretty consistently in ketosis for the past two years, do you think these issues are a cause for concern? Is there any way to mitigate thyroid issues from occurring on a long term ketogenic diet?

    • Perhaps, just be sure to distinguish between CLINICAL hypothryroidism and LAB hypothyroidism. The former requires intervention. The latter does not.

    • Patrick R.

      Thanks for the response.

      Additionally, I have been reading a lot of Ray Peat’s & Danny Roddy’s articles regarding PUFA’s and treating hyperglycemia as part of an adaptive reaction in diabetes rather than the cause of diabetes. Also there are the implications of ketosis acting as a stressor on the body due to more readily freeing fatty acids as well as increased cortisol and estrogen production for lack of glucose. Ray argues for a diet higher in sucrose/fructose in order increases metabolism and overall health sans weight gain.

      While personally, since beginning my N=1 experiment, my BP has dropped to normal levels, my BMI is now normal rather than overweight, my fasting glucose and waist have both shrunk, and all other bio markers of health I have tested thus far have improved, I am curious if this was solely due to the restriction of sucrose, or an overall improvement in my diet.

      I am curious to your thoughts regarding such research showing an opposing, but healthful view of the other side of the coin. If we are viewing insulin resistance as the main cause to metabolic syndrome, and a solution to insulin resistance is ketosis, do we also view ketosis in general as a healthy state?

      I ask this not for a personal recommendation on my N=1 but for your opinion on the overall view for people utilizing ketosis as a longer term diet targeting overall well being.

      Ray Peat articles on sucrose

      Danny Roddy’s comments on Ketosis (summary of Ray Peat’s analysis)

  • Mark M

    My crazy question (we all get one, right?):
    My very beautiful wife complains that years of very vigorous training (6 days a week/intense cardio/some weights/some boxing) combined with years on a very low fat diet have decreased the size of her breasts. I couldn’t care less, but she cares. So, having read a fair amount here and Gary Taubes’ book, I am convinced that hormones (growth, sex, and insulin) play a huge but not exclusive role in how much fat the human body stores and where it stores it. Is it crazy to hypothesize that a low fat/high carb/low calorie diet might result in more fat where the insulin will direct it (mid-section) leaving less fat for the estrogen to direct (breasts); and a high fat/low carb/no sugar diet might result in less fat where the insulin would direct it (mid-section) leaving more fat for the estrogen to magically direct (breasts) in post-pubescent but pre-menopausal women?

  • Ron Webb

    Peter, I am a 62 year old runner. I compete in a series of races in the Arkansas Grand Prix. They are from 1 mile up to a 1/2 marathon. I know I can probably compete at full potential from 5K up in a 1/2 in a NK state. But what do you think about 1 and 2 miles. Do I have to worry about carb loading in distances that short?

    • You need glycogen, but use the formula I’ve outlined to estimate it. We’re talking about up to 10 min of all out running This can’t use more than, say, 200 kcal. The issue is more about training, where you’ll run multiple intervals. There is no need to load for such a short event. Fuel partitioning is more important for most.

  • Tom Hughes

    I wonder if you wanted my experiences to add into the mix? I have been doing similar stuff to be, ketogenic triathlon, not ironman this year but half ironman, then ironman next year.
    We have briefly discussed on another thread that I have had similar experiences to you with regards to carbs and ketosis, in that I can sometimes consume upwards to 200-300g of carbs and not only still be in ketosis but record very high levels 4-5mmol, just hours after this consumption around long hard training.
    I have also never noticed a drop in my top end, like many seem to have experienced.

    Anyway, I have been ketogenic now for a while, not far off a year. It has given me much greater metabolic flexibility.

    I decided to test this ability to run on my own fat stores with a half ironman earlier this year.

    It was a fairly hilly race, both bike and run. I ate at 6pm the night before, then no breakfast and consumed only water. In the race i felt great, about 50th out of the water, 8th coming in off the bike, ran up to 3rd on the run, got to mile 9 out of 13 and bonked spectacularly, I could barely walk! Had a gel and finished 7th, and this was a national level race with the first 2 pro athletes so not too displeased.
    But I found out that I could go for just over 4 hours on water.
    I had averaged nearly 300w on the bike, so I was pushing it a bit and there were many many hills, normalized power was about 320w.

    So I learned a lot.

    I raced again this weekend, this time, I had a keto shake for breakfast, with a bit of coconut milk, oil, spinach and cinnamon, yum! On the bike I had some vitargo, about 2 scoops max as I didn’t drink much of it, so around 50g of carbs, or 200kcal. Then nothing on the run. I made up for my lousy swim, running through the field to come 2nd with the fastest half marathon by over 5 mins, finishing only 1 minute behind the winner who took 7 minutes out of me on the swim!
    I honestly think if the races were reversed (this one was flat) I would have been fine on nothing in this one.

    I don’t have RQ testing to indicate my level of glycogen utlisation etc. but I am guessing it must be at a pretty high intensity as I was pushing hard for the whole race of 4 hours, which living very low carb (and no carb loading at all prior to race) I don’t think I can have much of it!

    Next year I plan to take my experiment to full ironman where I am aiming (and don’t laugh) for around 8 and half hours. based on the fact that I felt like I could have biked all day at that intensity and run a full marathon no problem (I’m very efficient when running).

    Thanks again for all your info Peter.

  • adam y

    Peter – some very interesting new products out on the market that are keto related. the one i am most excited about is called “KETOFORCE”, by a well regarded nutritional chemist Patrick Arnold. it’s BHB in a bottle, supplying your body with exogenous ketones on demand. it’s quite interesting. he’s done some work with a leading researcher in the field. Instant Ketosis. elevates blood ketones significantly for 3-4 hours after ingesting. it also seems to lower blood sugar. i’ve taken it a few times pre workout, and have had some of the best workouts of my life, with ridiculous stamina. Users are either using the product as a) a pre-workout in order to boost endurance b) a transition product to help your body ease into ketosis while eliminating a lot of the transitory side effects such as fatique, brain fog, etc as your body becomes keto adapted. i really enjoy the product, and feel it gives me energy, mental accuity, and great work outs. it’s a bit too expensive to use on a daily basis, but i think this sort of product has a place in the market. as of now, they can;t market it for “medical” benefits, but it certainly has a lot.

    what are your thoughts on a product like this?
    more info on

    • I’m very familiar with it and Patrick’s work. Will discuss in due time.

    • Martin

      I wonder how much better it is than the plain old MCT oil 🙂

  • To your knowledge, is the HOMA-IR model being used (adopted) more in clinical practice than I am simply aware of? I’m not a clinician but from what I’ve read it SEEMS like it would be a good idea as a screening tool. Fasting glucose and C-peptide are easy enough to obtain, but most of what I’m getting back from PubMed concerns POS and Gest. D. I wish my doctor had known about it when hints of my metabolic syndrome began to show up. I had never heard of it until I began reading your blog. The RIAD study published out of Germany back in 2002 (Henkel, E. et al.) is interesting. Especially the correlation of IR and higher levels of Plasminogen-Activator-Inhibitor. I was reading that part as I was taking my b.i.d. 81mg enteric coated ASA and 100mg Nattokinase. Gotta cancel out that one bad copy of Factor V Leiden I inherited, coupled with IR, somehow.

    • HOMA-IR is pretty widely used, but it’s not very accurate at predicting IR relative to the gold standard — insulin suppression test (IST) or euglycemic clamp, which is not quite as good as IST, but is used in research settings a bit more frequently. Best “simple” test is probably 60 min and 120 min insulin response to OGTT.

    • Jacob

      Hi, Peter, quick question for you: I’ve read that if one eats a low-carb or ketotic diet one should eat at least 150g of carbohydrates daily for three or so days before an OGTT, to avoid getting a false positive on impaired glucose clearance due to transient insulin resistance. Should the same protocol be followed before the test to get a proper reading on the 60 min and 120 min insulin response?

      Many thanks

      • Yes, this appears to be correct, just as you’ve described. Probably true for the more complex tests also. BTW – a properly done OGTT gives you 60 and 120 min insulin and glucose response.

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  • Martin K


    Thanks for providing such a wonderful forum and being so engaged with your audience.

    I wanted to hear your thoughts on this recent study reported on by Gina Kolata.
    People are beginning to accept that there is more to obesity than “calories in/calories out.”

    If the causes of the obesity epidemic involve not just human physiology, but also the ecology of the bacteria in our digestive systems can we ever hope to “prove” exactly what all those mechanisms are? The human fetus is sterile, but it must be colonized by bacteria to survive, a hugely complex and variable process. Can science ever find the mechanisms by which processed foods, for instance, upset our bodies natural balance, both with regard to physiology and to the microbiome? Or should we look to the ideas of the natural foods and/or “paleo movements, and cut the Gordian knot?

    • This effect has been noted for several years, in fact, it may partially explain some aspects of gastric bypass (e.g., resolution of IR before reduction of weight, suggesting gut flora change in response to biliary changes, which alters IR before reduction in adiposity). Very exciting topic. Of course, the obvious question — how does the foods we eat impact the gut flora?

    • Boundless

      > … how does the foods we eat impact the gut flora?

      This topic may be one of the next big things in nutrition (for those cut loose of consensus dogma, anyway). Over on the Wheat Belly blog, I see a steady stream of people who have quit wheat reporting acute re-exposure reactions. What’s that about? Dr. Davis also commonly suggests a course of probiotics to recovering ex-wheat eaters. Are these related?

      My conjecture is that goat grass (what modern semi-dwarf hybrid wheat largely is), and gluten-bearing grains generally, are violently incompatible with ideal human gut flora. And “ideal” means, among other things, preventing leaky gut, which is the starting point for any number of ailments.

      >> The human fetus is sterile, but it must be colonized by bacteria
      >> to survive, a hugely complex and variable process.

      Saw that and immediately thought: T1D?

      T1D is rising (and it’s obviously not because the modern fetus is eating too much junk food and not getting enough exercise). What does cause it? Might parental gut flora, and by implication parental diet, play a role?

      Based on reactions to one of Dr.D’s provocative posts, parents of T1D kids are generally denialist about what role parental diet might play, and are also not keen on using NK to manage the condition, but if progress is to be made, we have to be open to all the implications of dietary choices.

  • Hakim Hakim

    Dr. Attia,

    Ketones vs Carbs, can they co-exist? How about Ketones vs. Alcohol? Can they co-exist in some fashion as carbs and ketones do in your article?

    I’ve read that alcohol will kick you out of ketosis until your body burns the alcohol for energy first (because it takes priority being a toxin). Then once it’s used up your body goes back into ketosis? or does it go back to burning glucose?


    • Two separate issues — the ethanol itself and the sugar and carbs that often accompany it. The latter is obvious — beer and drinks make with juice will kick you out — but dry wine and hard etoh, less clear. Seems to be does dependent. Yes, etoh is typically a prioritized “nutrient.”

    • Andre

      from my testing it reduces ketones – as it obviously contributes energy and hence the body needs to produce less ketones – but not keto-adaptation, i got easily back even after bottles of wine (dry) or other non-sugary drinks (caipirinha with lemons w/o sugar + sucralose), though i gained weight when drinking too much, despite work out.

  • SusanneL

    Peter, can PEF, Peak Expiratory Flow change due to a ketogenic diet? I am on a strict ketogenic diet and train on a regular basis. When I visited a clinic at the hospital this week, I had 570 in PEF. If I’m not wrong this is quite good for a woman of 48 years and 161 cm tall. And also another test (not sure if it was Spirometri) turned out to be “very good and high on the scale compared to my age and size” the nurse said. Or are those testings and numbers just due to genetics?

    • Hmmm, not sure. Certainly RQ changes but not sure why this would change.

    • I can give a little bit of “correlation” on this topic. I have allergy mediated asthma which is not overly severe but it would always be a constant thorn in my side. Always there just bad enough to drive me crazy and the only way I could force it to go away as I have gotten older was to combine q.d. Singulair + Zyrtec, and I’m allergic to damn near everything in North America that’s not a food. After being on an ultra low carb diet for about 2 weeks I noticed a remarkable reduction in my “latent” asthma. All I have to take is the occasional O.T.C. Zyrtec if something is in bloom or if I dust a ceiling fan or something like that, or cut the grass. That will get me every time. I have always had very good spirometry results as well, mainly because of my size as most spirometers just aren’t really scaled for me just like the sphigmo cuffs. That and I grew up doing a lot of free diving in Florida so I have really good chest expansion. The docs could always hear the wheezing but the restriction just wouldn’t register on the spirometer results at all. My thought though is the low carb diet just reduced inflammation enough to make the issue go away for the most part. That alone is enough to keep me eating this way irrespective of how it helps with my IR issues. Maybe you had some low level inflammation in your airways that was bad enough for you to take notice now that the dietary changes have eliminated, or greatly reduced, it. Either way it’s a nice feeling. Breathing problems are just one of the worst to have.

  • Rawnaq

    Hi Dr Peter,

    Are there any existing or potential supplements that can enhance the ability of skeletal muscles to use ketones or hasten their adaptation to NK?

    Thanks for all your work,


  • Rawnaq

    I shouldn’t have said “enhance the ability of skeletal muscles to use ketones” since beta-Hydroxybutyric acid is technically not a ketone.

  • Paula

    just wanted to see if you had read this yet (in today’s WSJ):

    “A Drop of Blood. An Instant Diagnosis.”

  • Jeffr Johnson

    Beyond The Pale

    Really?! – Various fruit-loops have commented how Magnesium helps relieve cramps – you could have fooled me – the stuff is totally worthless in that regard –

    I take some every day to keep me as empty as possible so as to prevent a Hernia attack at the lower intestine/colon valve juncture – it works in this regard –

    What does help cramps?

    Oddly enough – one Green Stuffed Olive per day is totally effective – So – it’s either the Pimento or the Green Olive

    I could expand on this further by asking this salient question : -Does mean Black Olives or Olive Oil serve the same purpose ?

    Who knows – I don’t – and I’m not inclined to pursue the matter for the time being –

  • Hello,

    thank you for your post(s).
    I have a few questions:
    1. were cashews raw, roasted or soaked (in water)?
    2. what other source of carbohydrates would you (yourself) also eat during that ride, ifnot those you wrote you did?
    3. Do I understand you correct, that if the next week you know you will have a hard ride/triahlon (or whatever), you would eat every day the same as you did the past months and than ONLY DURING (not a day or a meal before or after that) you would consume carbohydrates? -> acording to your past or latest observations?

    Thank you.

    • 1. Roasted and salted
      2. Super starch, other nuts
      3. Correct – no use eating that much CHO when glycogen stores are already near capacity; only when demand is greatest.

  • A couple of questions;

    Do you know if taking a mineral citrate supplement, such as potassium or magnesium citrate, will stall ketoadaptation possibly because of the “extra” ingested citrate finding it’s way into the mitochondria and upregulating, or at least supporting, the Kreb’s Cycle through increasing Acetyl CoA carboxylase activity and thereby increasing Malonyl CoA, thereby INHIBITING Carnitine acyl transferase I? Does the body produce so much citric acid anyway that any extra you ingest is simply trivial? I was also wondering if you know of anyone else besides Prototype Nutrition producing BHB salts for sale to the general public? I can’t seem to find anyone else.

    • Great question, Dan. I don’t know the answer, but obviously it would be dose dependent.

  • Hello
    I tried looking for the answer for this on your site but couldn’t. I’m an Ironman triathlete and ultrarunner, I have been low carb for about 9 months now and started NK for over four weeks now with the aim of putting my pre-diabetic state in remission (family history of type II). How can I manage a ‘miss’ on NK? ie. taking my wife to a Thai/Japanese meal or having a glass of two of wine every now and then.
    I’m loving NK but it’s very antisocial at times so wondering how I could manage this.
    Many thanks.

    • Andre

      might seem so, but its not anti-social, though you have to get used to always be modifying orders/dishes/plates in restaurants, which in 99% works out without problems. in canteens you will be more selective, but thats not a problem, as you can just hold out until you get some proper food.

      japanese is easy: sashimi, hand-maki w/o rice, edamame, fried fish & sea food w/o sweet sauces. yes, no rice.
      thai: replace rice & potatoes with lightly steamed broccolis or other greens, i do it all the time, it tastes even better now. I say broccolis because its usually available.

      wine/sake will – according to my exp – pure alcohol (ie, not beer) will not throw you out of keto adaptation, but may reduce them for a while, i did some testing, even with some bottles of wine, i always had ketones. as far as my understanding goes, alcohol will be burnt with preference, probably thats why you get extra drunk and dont need that much and probably doesnt cause an huge insulin response (or else i wouldnt have ketones).
      however, naturally, the calories in alcohol will be found in you belly, like every calorie, unless you spend it. i noticed weight gains frequently when missing too much on alcohol.

      when in ketosis, eating a keto meal and drinking alcohol AND THEN on top having a sweet desert (1-2 a year that slip happens) I will become usually kind of hyperactive and my body will make me burn as much as possible.

  • leslie

    Have you noticed your resting pulse rate going up as a result of ketosis? Mine has gone from 42 to 68 over the last four months of being keto adapted.

  • Mark

    Interesting stuff but I can’t help but read your work and think.. “man.. he is way over-thinking things”.

    The level of carbs/fats just doesn’t matter if your overall calories and protein are right. Those 2 variables equal, you’ll get just as lean upping the carbs or lowering the carbs.. but you won’t look as good unless you up the carbs.

    It really is that easy.

    • Martin

      So you are saying that with the constant amount of protein, let’s say 1-1.5g per kg of lean body mass, in my case 70-105g/day, I could limit the fats and add carbs as the main energy source and I would be fine?

  • Great Post!

    3 questions.

    1. Does it matter when you consume carbs after some glycogen depletion. I know you did after the workout because of the window of depletion and insulin sensitivity. But if I am glycogen depleted, would I still be able to slowly refill it over 24 hours?

    2. Volek and Phinney advise not taking in carbs after working out. But it seems it primarily has to do with fat loss. If the goal is fat loss, would you also advise not consuming carbs after exercise?

    3. What is your favorite Quest bar? (mine is White Chocolate Raspberry and Apple Pie)

    • 1. Not as much as people think… When glycogen is depleted, assuming you’re reasonably IS, priority #1 for ingested CHO is replenishing glycogen.
      2. I’m not sure I see why. Highly dependent on type of activity. It’s true that ingesting CHO right after workout may increase RQ, thereby reducing fat oxidation, but not by a great amount, especially if glycogen levels are low.
      3. Cookie dough, but I think it’s evil, it tastes so good.

  • Owen

    “John, I’m pretty sure I’m looking at more data than you are.”
    Best answer ever ….

  • Tom Hughes

    Can I ask your opinion on a question that has been floating around my mind.

    In regards to the race scenarios I have posted above. I keep on thinking, in the first race particularly I started to feel a bit low shortly after I had started to drink a bit of the carb drink I had on the bike, it was a very very weak waxy maise starch solution. I barely had any of it, just sips.
    Obviously then I went on to bonk.

    Could the bonk have been CAUSED by the small amount of carb I ingested? It was on an empty stomach, so could the small amount of carbs caused an insulin response leading to shutting off of endogenous (fat) fuel usage?
    I can’t help thinking that I would have been better if I just stuck with water.

    This has led me to believe that it is better for me to either have no carbs at all, or have lots and lots of them and keep fueling with them regularly.

    • Hard to say, if you’re insulin sensitive to begin with a small dose of CHO in workout is not likely to spike insulin much at all.

  • Hampus Arvidsson


    First let me say how much I appreciate all the self-experiments in pursuit of knowledge and for the passion with which you follow science, wherever it might take you.

    This might depend on bodytype, technique, figtingstyle etc but
    my question to you is, do you think keto-adaption would be beneficial for MMA athletes in general?

    • Great question. I am not sure if keto-adaptation would help, but I do suspect a more measured (vs. unrestricted) approach to CHO would be beneficial. I do work with some MMA trainers and they definitely do best on diet low in “cheap” carbs.

  • nuno

    I’m actually typing with a distinct feeling of pleased discomfort, as i tap keys with recently lanced finger tips for the purpose of glucose/ketone testing. 🙂 I have 2 days until the Collingwood Centurion near Toronto, and apparently i was already in a mild NK state (.5) without even knowing what that meant a scant 3 days ago. This is all really good stuff. If i could drink this blog i would be drunk on facts and wondering if that alone would lower my insulin levels (psychosomatic testing has proven to be inconclusive). I do have a question amongst the wordsmithing however. Where the heck do you do RQ testing? Google doesn’t seem to have an answer for this. Hopefully it isn’t strictly reserved for the revered acolytes of medicine amongst us.

    An inquisitive mind that humbly acknowledges how little i understand about my own body.

    • See post with video link to IHMC talk (2 or 3 posts ago).

  • Alexander Dreyzen

    Here, I describe 13 years of my experiment in glucose starvation and high intensity interval training.
    About half done.

  • Jack

    Hey Peter,

    I’m a professional baseball player and big fan of the blog. Although I’m not sure ketosis is for me, it seems like a no brainer to eliminate sugar and other processed carbs.

    My training (and pitching itself) is pretty much all anaerobic, so I’m wondering if you see a problem with having either carb intake or protein intake, or both, slightly above the threshold of achieving ketosis? Is there a gray area just above ketosis where you don’t reap the rewards of either full ketosis or having adequate glycogen repletion over time?

    I know you said you felt terrible 8 weeks in when your protein intake was too high to reach ketosis, so I’m wondering if limited carbs but higher protein would present a problem.


    • Jack, you’re a fellow Stanford alum, right? Agree that ketosis might not offer a huge advantage to a pitcher (though some, like Volek, would argue ketosis spares amino acids greatly, and therefore offers an advantage to anaerobic and strength athletes, also). A diet low in added sugar and high GI carbs, with compensatory increase in protein and fat (MUFA, SFA over n-6 PUFA, probably?) would probably work well. You may like the Gen UCAN product, super starch.

    • Jack

      Ha, yes, I am. Lots of good memories there. Okay, thanks for the advice. I’ve got about a 5 month off-season coming up, so plenty of time to experiment with it.

    • GeorgeN


      A couple of thoughts for your situation.

      One, on a low carb site, one guy commented that any degradation in performance for anaerobic activity went away when he kept his serum ketone level above 2.0.

      Second, I’ve been keto-adapted for 5 years or so. My interpretation of what happens in keto adaptation when you carb up is that your ketone production drops dramatically till you deplete those carbs and then you start making ketones, as needed. This does not require readaptation, in my experience. I view it as keeping the big tanks (fat/ketones) hooked up but with the valve not turned on until needed. I can stay just above the NK level for a few days or a week, and then drop back in by a) being really strict with the diet, b) intense exercise, c) fasting for a day or day and a half or d) some combination of these. The ketones seem to come back when needed. I do try to make sure I’m nice and well into the NK zone periodically so I don’t un-adapt. I really don’t know what the unadaptation time frame is and haven’t experimented to find out. I’m not optimizing ketone output, but still experience many benefits. My RQ must be better as I don’t breath hard at high altitude (I live around 5,600′ but play a lot at 12-13,000′ in the nearby mountains with highly fit friends). I never “have” to eat. I can do hard activity all day without needing to eat (I usually only eat breakfast and dinner anyway). I almost always exercise fasted. My water intake requirement, especially at altitude dropped dramatically. One of my avocations is downhill skiing. I’m 58 and one of my friends is a very fit, 27 year old ski patroller. He tells me I’m the only one of his friends that can keep up with him, even those his age. I attribute this to the keto-adaptation.


    • Jack

      Thanks for the ideas, George. Going to experiment with it.

  • Gregg Curry

    Simple request; I searched your blog for your hummus recipe. Any chance you can post it?

    • It’s posted in response to an earlier comment.

  • Dan Walker

    Okay so I’m crunching away on all this metabolic biochemistry trying to make sense of keto adaptation at the cellular level and I’m really curious to know if I am even close here. Basically, through macronutrient manipulation one is causing their carbohydrate mediated version of overall energy production through the Kreb’s cycle to stall by exhausting glycolytic based substrates and then re-priming the Kreb’s cycle to flow using substrate that is derived soley from ketone bodies which in turn are derived from FFA either consumed, or released from adipose tissue and then processed by the liver. I’m guessing this is a gradual process moving through some type of progression from whichever organ system, and its associated tissues, would be the quickest to shut down glycolysis to those that would be more resistant and shut it down the slowest. I can’t seem to find any other processes by which ketone bodies can be oxidized for ATP production except aerobically back in the Kreb’s cycle. Some of what I’m reading actually is suggesting that overall ketone bodies MAY be an even better substrate for Acetyl CoA than Pyruvate and generate even fewer ROS byproducts from the ETC.

    • Dan, mostly covered in the 2 part series of ketosis I did a few months ago.

  • Boundless

    > … In ride nutrition … 2 Quest bars …

    Prior to your posting that, Amazon could ship an order of these bars immediately. Now they’re back-ordered by nearly a month.

    On the conjecture that this is no coincidence, perhaps you could use your apparently considerable influence to get Quest Nutrition to formulate a line of proper keto bars (the current bars are way too low in fat, and possibly too high in protein).

    • Funny you should say this…doing exactly that. Stay tuned.

  • Jeff Johnson


    Potential Energy ——— Actual Energy (the end result)

    This is a simple equation that permeates life as we know it – it applies to more or less everything – including diet –

    Forr the sake of simplicity – everything in the diet and diet modalities (such as fasting) -can be given a 100% Potential – the quality of the substrate being the main limiting factor and genetic varibles –

    For this potential to be realized (Actual Energy) – (our product – the end result) -:is shown by the following example’s –

    For those eating high fat daily – the (actual energy)/benifit is somewhere near 0% –

    To fix this – one only needs to limit fat to near zero one day per week and the other six days high fat –

    This one simple change means the difference between no benefit (movement towards death) and maximun benefit(the proloning and quality of life)

    The reverse is also true – those eating a low fat diet should include one day per week that is very high fat – this would fix many of the problems with this sort of diet –

    This same sort of thinking applies to proteins – carbs – fats – and fasting modalities – to sum up – eating the same way seven days per week – month by month – year in year out – causes a movement towards malfunction in some way or another and is not correct –

    The curious thing here is – this is exactly what people do in general

    A simple one day per week adjustment is enough to fix this – as the Lion – he eat’s one day per week and fasts the other six – (I don’t mean this specific modality for people – simply that one day per week needs to be the opposite of the other six –

    Imagine an Earth (this planet) – where it was sunny 365 days per year – no rain – life would quickly disappear and if it rained 365 days per year the result would be similar –

    Regardless of what diet a person follows – there is something wrong with it – substrates and genetic variables and the daily moldality it-self are never perfect – one day per week should be used in a correct manner to fix this –

  • Alexander Dreyzen

    Hi Peter,
    I just watched the “Advanced Metabolic State” video that you linked at the top of this page. It’s remarkable how much your experience is similar to what I have been doing. I am not nearly as rigorous and data driven as you are. One question that I didn’t see you address, is what adaptations happen when one is chronically low on glycogen, while at the same time forcing extreme bouts of exertion from 15 to 40 minutes long up to 5 times a week, as in a CrossFit WOD. SNS, mostly through adrenalin, seems to do the trick for me, because this is what (from what I have been reading) kick-starts release of free fatty acids from the fat cells. I do get this sensation that my heart is about to jump out of my chest before I even start the WOD. This is how I have been training for years. There are some papers in PubMed about the benefits of low-glycogen training, but they only talk about “train low, compete high”, not “train low, compete low” protocols.

    I would appreciate your thoughts,
    Alexander Dreyzen

  • Chris

    Dr. Peter, I found out about you from a recommendation of Tim Ferriss. Honestly, in the past two to three weeks I’ve been researching NK and I have to say that your experiences and videos are the most appropriate from all resources. One thing that I know it’s great and I know you recommend it as well is the research of doctors Volek and Phinney.

    I’m currently reading their Art and Science of Low Carbohydrate Performance as I do a lot of exercising (both cardio and strength training). One question:

    Do 3 fully body workouts in the gym (Tuesday, Thursday, and Saturday – 20 min strength with 8-10 repetitions with 80% of the weight that I can do 1 rep + 20 min of cardio) + 3 kickboxing sessions of 1 and half hours each (on Monday, Wednesday, and Friday) are too much for muscle gain on a low carb diet (with high fat high protein).

    I know you are very busy, but give me the easiest and least time consuming answer that you have on this.
    Thanks Doc, really appreciate everything you do!

    • Chris, depends on too many factors for me to give you a yes or no answer.

  • Bennett Johnston

    Two quick questions, but first I want to say that I LOVE your detailed, evidence based blog. You write truly life-changing posts. I’ve been “paleo” for years, but your and Gary Taubes information takes my understanding to a whole new level.

    1) I searched your site, but I couldn’t find whether you ever posted the FAQ slides from the end of this talk you did for JumpstartMD in Summer 2011 (the end of the video gets cut off).

    JumpstartMD Video –

    2) In The Interplay Between Exercise and Ketosis Parts I and II, you touch on the phenomenon of blood glucose increasing during and post-workout (even when no food is consumed before or during workouts). I believe you mentioned that this increased BG seems to have no effect on your being in / out of ketosis. My question is, if increased BG –> increased insulin secretion –> fat accumlation, does that mean working out promotes fat accumulation? I’m not trying to oversimplify, I’m sure the answer is not straight forward (like most things). What if you’re NOT in ketosis to begin with and working out?


    • 1. No, never posted
      2. Catechol surge, plus increased demand for glycolysis increase HGO and blood glucose rises. This is almost always met with a fall in BHB (and AcAC, I suspect, if we measured it). But there are reasons for this — the rise in glucose (and insulin that follows), and the reason this is happening in the first place, the body is demanding energy at a very fast rate. The latter is driving down BHB and “asking” the liver to breakdown glycogen quickly to release glucose.

  • CBart

    Hi Peter,

    I am pretty new to this whole LFHC thing but have become interested in it after reading that Joe Friel has adopted this lifestyle and is functioning well on it.

    I am a category 3 cyclist that trains between 6-12 hours a week on average. I started the new approach to eating about 3 weeks ago cutting my carbs down to about 50g a day and increasing my fat consumption. The first few days were pretty tough as I have lived my whole 43 years on a high carb American diet, but after about a week I was feeling good and the cravings for sugar went away. BUT, I noticed that my cycling went downhill fast. On a ride that normally I would consider an easy or moderate ride/pace I found I fatigued really quickly, had heavy lactate filled legs and took a long time to recover. It was enough that after a few more rides like this, I dropped off the diet all together.

    After a couple of days back on carbs I went for a ride and felt fine. I even included 3 8 minute intervals at 270 watts and never got any lactate and felt fine the next day. But I still wanted to stick with the LCHF diet because I think in the long term it will provide better health and energy day to day, so I have gotten back on it. So I have now been back on it for 4 days. Not really having any cravings for sugar but back out on the bike I am right back where I started. I went for a pretty mellow 2 hour ride 2 days ago staying mostly in the endurance power/HR zone and felt really tired at the end and now 2 days later the legs still feel tired.

    I have searched high and low but can’t really seem to find to much on the web with people experiencing similar problems.

    Wanted to see if you had any thoughts on this and if you experienced anything like this when you switched over to a low carb diet.


    • Yes, written about extensively in the blog and throughout comments. Sorry I can’t re-describe. Will take hours, but it’s all there.

    • CBart

      I understand. I will continue to search. In the meantime should I expect it to pass or do you think I should include more carbs on workout days pre/post ride?

  • Coco Guerrero

    I wish I had found your blog sooner! I have been experimenting with my diet for the last 9 months all with the basic premise that I’m IR and that my weight is a product of not understanding/treating that. I have no medical background or knowledge but have been reading incessantly and had pieced together much of what you explain here. What has brought me serious progress in my weight loss was understanding the IR and focusing on that-as oppososed to weight loss (a distinction that you have repeatedly noted). This simple shift in mindset has had profound consequences for me and my family.

    What made me focus in on the IR was the experiences of my pregnancies (I have 4 children). I read about how IR is normal in pregnancy because it helps facilitate the transfer of nutrients to the fetus. Supposedly, shortly after birth the woman would revert to normal insulin sensitivity. I started wondering if a woman was unaware of this temporary IR state and resumed (or maintained) a “normal American diet” would this set off a snowball effect that essentially prevented her from resuming her pre-pregnancy insulin sensitivity? Anyways, the idea was enough to eventually lead me here 🙂

    Also, I think it would be helpful if some research was devoted to the transition into LC. As you mentioned in another post, even if you know WHAT to do, it doesn’t mean you can make it happen as easily or quickly as you’d like. I think science could have much to contribute here ;-). I have figured out some of my triggers that will set me off course, and I have found some supplements or key foods that support or help me stay on course, but I sure wish there was more solid data in this area.

    Thank you for publishing your experiments and taking the time to explain the science behind all this…so glad someone with the credentials is able to think outside the box!

    • Coco, it warms my heart to know that focusing on IR (vs. weight) has helped you and your family, as I really believe this is the jugular issue. I’m not sure I know the answer to your question, but there are several physiologic states where being IR can help, and some degree of this in pregnancy is likely an example with profound evolutionary pressure. Of course, the post-pregnancy phase, may be another story, as you suggest. To your second point, a lot of us do speculate on exactly what this transition means. For example, is something occurring in the mitochondria? I suspect it is, but we need more science to know for sure.

  • Allen W.

    Dr. Attia, I have a question about Acetone. I have watched many lectures on Biochemistry from online courses trying to get a better understanding of how cell metabolism works to break down substrates into energy and have a loose grasp on Glucose/Fructose/Galactose metabolism and on Fatty Acid metabolism. For the Ketone bodies I understand how acetoacetate and ?-hydroxybutyrate are metabolized through the Acetyl-CoA pathway as well. I had heard multiple times however that when acetoacetate spontaneously degrades to Acetone it becomes strictly a waste product and the body expels it via urine and respiration.

    This morning I stumbled across which states that clinical investigators in 1979 established that Acetone is not just a waste product, approximately 70% of Acetone formed from acetoacetate in the blood is processed by the Liver into Glucose and Protein structures.

    If this study result is accurate then all three of the ketone bodies are very useful for human metabolism, with the Acetone supplying a second source of Glucose along side the Glycerol from the Triglyceride molecules. I would like to believe that this is the case as it would explain how people on strict carb restriction are able to regenerate Glycogen in their muscles much more efficiently than if only the Glycerol and Glucogenic Protein bodies are involved.

    Is Acetone a useful substrate, or just a waste product? If it was proven a useful substrate way back in 1979 why do biochemists still teach that is is a useless waste product?

    • I’m not sure if this is saying acetone is used, per se, for fuel, or just that it rises when other fuels are being produced and used. I’d have to look further. In most folks who are keto-adapted, breath acetone starts to go down, as AcAc use goes up. But I will dig further.

  • Jack

    Hi Peter,

    After your body is adjusted to Ketosis (I assume it takes about one full month) and then you binge on carbs for one day, does your body need to readjust to ketosis all over again after that binge day?


    • Depends how long you’ve been adapted. Today, I can slip out with carb- or protein-rich meal, and be right back in the next day. Used to take 2-3 days to rebound. 4 hours of 60-70% VO2 max is a great boost, too!

  • Alexander Dreyzen

    One of the most exciting new ideas in metabolism that I have seen in a long time, is the idea of adipose tissue plasticity. If in essence, WAT cells can become BAT cells, when they lose much of the triglycerides in them, then, as we lose fat, our basal metabolic rate may actually go up, not down, as the cells switch from storing to burning energy. In the past I was lead to believe that as we lose fat, our metabolism slows down to preserve the stores we have left.

  • Andre

    Peter, now that you mention inflammation/SIRT, I was reminded of some stuff I read re LDL/colesterols involvement in immune function, as I am apoe e4 my colesterol is extra high and I read that high LDL is supposed to improve immune function and also that ketogenic diets improve recovery after workout.

    I am mostly in ketosis since dec/2012, with (unfortunately) only 2x long distance a week, but my total colesterol is way higher, than before. In addition to all the common benefits that I experience, I have noticed, even though I still travel weekly by plane, that I havent had a cold pretty much since then, which is strange, since before the ketogenic diet I cought colds frequently.
    In addition, since the beginning of the year, I seem to be more sensitive to mold, especially when contained in sesame products (as they frequently are).
    Might be coincedence, but as all of this has to do with immune function…

    Any idea or possible future blog post about that (colesterols spike on keto diet impact on immune function)?

    • Not sure I know enough about this specific reaction to write about it, but I do have one more post in the long overdue series of cholesterol somewhere in me.

  • Allen W.

    Dr. Attia, in my searching around the web today I discovered the EPA Toxicological Review of Acetone from 2003.
    which was written as a guideline for assessing persons with chronic or sudden acetone exposure from their work environments using it as an industrial chemical.
    The section I think you will find of interest is section 3.3 Metabolism of Acetone, which gives a list of prior studies used to study both endogenous and external exposure. Page 16 of the .pdf is the beginning of the section and page 25 gives a complete diagram of the two main pathways for the body to convert Acetone into Pyruvate. One pathway is Hepatic and the other is a whole body pathway that becomes active at high Acetone concentrations in the blood. The diagram includes the names of all the intermediaries and the enzymes that process the substrates through each step of the process for conversion to Pyruvate and entrance into either the Kreb cycle or Gluconeogenesis.

    I am stunned that all of this information was published in 2003 but the biochemistry course book I downloaded last spring makes no reference to Acetone as anything but a waste product. Perhaps I am just not understanding what I am reading, college chemistry was over 20 years ago for me and I never used it for anything after graduation.

    Thank you for all that you do, and if this is a real biological pathway for converting Ketones into Glucose I hope someone can make use of it in understanding how Dietary Ketosis functions on a deeper level.

    Allen W.

    • Very interesting. Thanks for digging up. I wonder how much of this actually takes place in NK (vs. acetone overdose)? I would still guess the answer is very little, but I love learning new biochemistry.

    • JR

      Chris Masterjohn has an article out there about how, contrary to previous understanding, fat can actually be transformed to Glycolytic consumables via the Acetone to Pyruvate conversion it seems you are referring to…

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  • Meredith

    I do have a question but it is not related to your most recent blog post – well, maybe it is in a roundabout way! Would you comment on the recent release of Grain Brain by Dr. Perlmutter? I am assuming here that you have read it or will be reading it. How does this all relate to what you discuss here – should we be all going into NK or cutting back severly on carbohydrates? My personal experience has been that I have found it impossible to go into NK while eating vegetables and fruit. I am seriously considering eliminating fruit – is this “safe” nutritionally speaking? I am convinced thru reading your blog and various other sources that cholesterol and dietary fat are good and I have every intention of sharing your blog information with my GP who insists on drugs to lower blood cholesterol…..

    • Meredith, I knew it was coming out, but have not read it, so can’t really comment specifically on it. I don’t know that eliminating fruit is necessary or even ideal to maximize brain health, though there is no real evidence that fruit is “necessary” for health, despite all the propaganda to the contrary.

  • Tim Lewis

    Dr. Attia,
    For the last three weeks I’ve been eating LCHF and in general, getting along well. I’m consuming about 30-50g of carbs/day. I ride/race bikes and I’m preparing for a 12 hour mountain bike race as well as a season of cyclocross. My hope was that I could be ‘fat-adapted’ for the long race and use the cyclocross races as much for training as anything. I always keep a very close track of my ‘on bike’ data including heart rate and power. I’ve noticed some interesting trends.

    First, at anything over about 200 watts (right at 60% Vo2Max for me) I ‘feel’ the effort. If I stay below 200 watts, I can go forever, but there is pronounced transition point there. Recently I did a couple ‘hard’ efforts. I rode at 250 watts (essentially an SST effort) for 10 minutes and had to work like hell to do it. I should be (and previously have been) able to ride at this effort level for an hour to an hour and a half. It absolutely was not happening.

    Here’s another thing I’m noticing. My heart rate is through the roof on the bike. This 250 watt effort was at an average of 163 bpm a couple weeks ago. Yesterday I averaged 191 bpm. My lactate threshold is at 183 bpm, which puts into perspective how hard I was working to produce these numbers.

    So I’ve been thinking about my experiences and here’s what I’m thinking. Let’s say my RER at 250 watts used to be 0.9 and now it’s 0.8. That means I’m burning a lot more fat and a lot fewer carbs, which was my goal. Only that’s just some of the story. The rest of the story is that fat, being an ‘aerobic’ fuel, by definition takes oxygen to burn. If we’re producing this power by burning fat instead of carbs, then we’re using more oxygen. If we’re using more oxygen, then that means my lungs have to pull that oxygen in and my heart has to deliver it to my muscles. The increase in heart rate is a completely logical consequence of the increased fat burning.

    Here’s the strange thing. You haven’t mentioned it. Noakes hasn’t mentioned it. Volek and Phinney haven’t mentioned it. Everyone talks about the RER change, but no one has mentioned the implications of this, which I’m now experiencing. The loss in performance on any effort that is tempo paced or above is pretty massive. This is not a situation of “I’ve lost a little top-end”. This is a situation of “I’m taking a knife to a gun fight”. I’m wondering why you guys are all glossing over this. It’s a _big_ deal. What’s up?

    There are aspects of the LCHF diet that I like. The consistent blood glucose level and energy through the day is nice. The lack of hunger is nice. Eating high fat foods is a treat (although I’m beginning to miss fruit). I might have lost a pound or two (although, I was fine with my weight previous to this). Is there any way to keep the good aspects of this diet and at the same time address its short-comings in terms of power production? As it is, I may have to move away from this diet because the effects on the bike are just too big.

    Thanks for your insight and blog,

    Tim Lewis

    • Tim, I’m not sure I agree with your assessment, though I appreciate the length you’ve gone to in describing your experience. What you’re suggesting is that it requires more moles of oxygen per unit ATP when oxidizing fat than glucose. This is not the case. The reverse is true. What I suspect is you may be hypovolemic and that may be driving your tachycardia. Also, don’t underestimate the length of time it takes to adapt to efforts in around zone 3 and zone 4 (i.e., not just zone 5/6).

    • Alexander Dreyzen

      I also think that, since HSL is the limiting factor in lipid metabolism, especially since you are new to LCHF, you have to pump extra adrenalin to get the triglycerides cleaved. Just like an IR person, needs more insulin to drive the glucose in the cells, you need more HSL hormones to get the free fatty acids out.

    • What’s not to agree with.

      It’s the finding of studies on performance during ketosis. It’s fine for recreational athletes who don’t understand what high performance really is. They can make up the loss in performance by working harder since they never were working out near their max, and will get fitter and stronger and lose weight (suprise ketosis didn’t do it). You have to work harder to get the same result, and that the universal finding on RPE as well.

      Avoiding sugar and minimizing carbs for active types because large amounts in sedentary types may be unhealthy
      makes perfect sense. Folks, knock yourselves out silly.

    • Jeff Swing

      Dr. Attia, I appreciate the immense amount of love and work you’ve put into this site. It is an incredible resource. I find the discussions just as rich in information as the blog posts.

      I have seen a similar effect in the relationship between my cycling power and my heart rate since I started NK about 4 weeks ago. I’ve been riding easy in zone 1/2 while I give myself time to become keto-adapted in this off-season period. Holding my heart rate constant at 140 BPM (zone 2) for 60 minutes, I’ve seen my power drop from 192 to 174 watts. I did not see an effect when I started supplementing with bouillon about 2 weeks ago; I try to get 4 to 6 g of sodium daily. I’ll post again if things change or I figure it out.

      A few questions:
      1. Tom, any update on your cycling performance?
      2. Dr. Attia, how does one tell that they are keto-adapted? You mentioned previously that it took 2-3 months for you to adapt, what was your success criteria?
      3. Dr. Attia, I’m inferring in these comments that each power zone adapts at different rates. Or does it take time in each zone to cause adaptation? How does it work?

  • Tim Lewis

    Dr. Attia, thanks for the feedback! Here’s some more information on me and where my thinking is coming from.
    I have tried to keep my hydration level consistent. I drink a lot of tea (usually decaf) and water. I have also been drinking 1-2 cups of bullion per day and see differences in my day-to-day weight which seems to tie back into the amount of water I’ve retained (and how much salt I’ve consumed). So do I have blood volume/hydration issues that connect back to my high heart rates? I really don’t think so. If it is, then it’s just a single component of the issue and probably not the largest one at that.

    When considering the amount of oxygen it takes to use fat as opposed to carbs, my thought process goes something like this. First is the terminology. The word ‘aerobic’ means ‘requiring air’. The word ‘anaerobic’ means ‘without air’. Fat is an aerobic fuel and glucose is an anaerobic fuel. Certainly, an aerobic fuel will use more oxygen than an anaerobic one?

    In The Paleo Diet For Athletes on page 88 it talks about fuel during exercise. It comments that, “Carbohydrate yields 5.05 calories per liter of oxygen, whereas fat gives only 4.69 – a difference of 7 percent. During aerobic metabolism, this 7 percent caloric advantage for carbs translates into a threefold faster energy production in the muscles.” Comments?

    As far as the adaptation time, I think there’s probably a lot to this. For sure my body is not completely adapted to this diet or working in this manner. I guess the drop in power in zone 3-4 (and the fact that anything above this doesn’t even exist anymore!) has been a surprise. I don’t know if this is a transitional phase or just the nature of a carbohydrate limited diet.

    What is a common adaptation time period? Have you tracked your cycling threshold power as your diet has changed? What fuel source is going to be used to replace the glucose as my body adapts more to this diet?

    • Tim, unfortunately, I’ve only started using a power meter on bike (outdoors) this year and a computrainer for 2 years prior, so these are not apples-to-apples. The concept of aerobic vs. anaerobic is sadly grossly misrepresented. The bumper sticker distinction is “with oxygen” vs. “without oxygen,” but this does not even begin to describe the differences. My only comment on the quote you provide is that I have no idea what they are talking about and find it irrelevant. Calories mean little. The question is oxygen consumption to ATP production, and this is where the distinction between aerobic and anaerobic becomes helpful.

    • Shane Wilson

      Tim, two years down the track now, and I inquire as to whether you have maintained NK and if you have noticed any change with power in zones 3 – 4. I have been LCHF for 12 months and have noticed in the last six months a dramatic drop in top end power (when cycling). Otherwise, my health is fine, however it would be interesting to know if your power has picked up.

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  • Michelle

    Please help…I just finished week 13 of low carb 30-50 gms per day. Everything is great…EXCEPT… my legs still feel horrible when I run. I don’t eat a lot of protein and I am adding salt stix, (sodium, potassium, magnesium, calcium and D3), which has helped some, but I expected my cardio to be back on track by now. It has improved from horrible to I can now mentally fight threw it to finish, but I have had ONE run in the last 13 weeks that even felt “OK”. What am I doing wrong???

  • doug spence

    Thanks, Dr. Attia, for the detail you report on yourself and the process.

    I have read in Drs. Volek and Phinney’s LC Performance book that excess protein gets turned into sugar and can lower the Blood Ketone level.

    So my question relates to protein and rebuilding muslces. When I have ran a long run, there could be either some repair to my muscles or a need for new muscle fibers to be created after the run. And to my understanding, it takes protein to do that. I have found that if I eat a lot more protein after a long run that my fasting blood ketone level drops the next morning, even when I consume the same amount of carb grams.

    Can I presume that I don’t need to eat more protein after a long run to provide the body with the protein to rebuild or repair muscles? Thanks for your time.

    • There is some evidence that ketosis preserves amino acids, especially leucine. Also, preservation of muscle is probably more about type of protein and timing of protein than absolute amount. So it seems one does not necessarily need to compromise anabolism.

  • jarrod

    I apologize if this has been addressed, I did use the search function. I’ve read that being in ketosis is an anti catabolic state. What are your thoughts?

    • Not addressed directly in a post, but throughout various comments. This is a bit of a myth, though probably true to some extent if doing it incorrectly.

  • LUCA


    Hi Peter. First of all thanks for all the precious time of your life you spend on sharing your experience with others. I love the way you are passionate about it and you pretty much got me to tears when i v watched your speech on TED. I have chosen you as a main guideline for my adventure in a better life by better eating and exercising because your approach is very passionate but yet scientific. You do not always give the truth as granted and you dont make anything up when you do not have answers.

    I have never been into the fast food tipical american diet but as an italian i grew up with pasta bread and pizza as the staples of my diet.

    I am now 36 and have always been pretty overweight with peaks of 10/15 kg above ideal weight. I have always assumed it was due to lack of exercise but i was wrong. Well that didnt help of course… but when 4 years ago i decided for ethical reasons to become a vegetarian first and then a vegan… i didnt just start gaining even more central fat but i became very weak and depressed all the time. B12 supplementes didnt help. nothing helped. not even summer.

    I was still a vegetarian when a couple of years ago i have started body weight training, TRX etc.. that raised somewhat my metabolism and yes had great results in terms of gaining flexibility, strenght, resistance loosing weight etc.. but my results were obvious only during my training sessions not really in day by day life. as soon as i v had few days without training mood swings again.. feelin weak, tired and puting central fat on straight away. Also my triglycerides were 150!! My diet was based on fruit, vegs, starches, grains, heaps of pasta rice and pizzas, legumes (soy crap simil meat products!!) and no animal protein and dairy yet my lipids profile became a disaster with low HDL and high LDL and high trig. (funny at times i didnt even know they were high as i was just slightly before the upper lab ranges and assumed ah well its in the range must be ok then).

    The clear lack of B12 (supplements did not work not even with massive doses of the metyl form of it… methylcobalamin ) forced me into eating animals again. it was hard. but yes, after a few weeks i felt like i was the living breathing proof that we truly are omnivores and need to feed on that. My hair… fingernails.. skin… energy.. libido!!!… i was alive. again!

    The issues related to sugar spikes… random sleep patterns, anxiety and energy rollercoaster was still there though.

    and then.. then the revolution started. in the first phase i started buying Organic grass fed beef, free range bio eggs, organic green leafy and cut off gluten. but Still mood swings and fatty fatty with al the high fructose fruit, rice, potatoes, sweet potatoes, buckwheat cereal flakes in the morning etc… i reckon i was still on a 400 grams of carbs per day.

    with more and more exploring i ended up with a book in my hands about low carb and then website by website blog by blog… found you.

    I have now been on low carb (around 100 grams a day) for about two months and been feeling great. I suspect i cant tolerate gluten as since i v dumped grains my stools are finally normal again and seems like i am absorbing water and nutrients in my colon. All my spikes of energy are gone. I can now for the first time in my life go to bed early and wake up early without alarm!! I have never been able to sleep before 1 or 2 am at least not since i was in primary school.. My fasting glucose is usual pretty high around 90 or so and i did noticed that on low carb it went a bit higher too as a paradox. Btw Peter, tested my insuline a week after i started low carb high fat and it was 5.7. A1C of 5. The HOMA-IR calculator gives me a 1.22 which according to your limit of 1 means i should be somewhat insuline resistant. (I hope this value will be lower when i re-test in a month). I suspect that before starting regular training two years ago and when my diet was based on carbs and starches it was even higher… u should have seen my love handles at time!

    I still have central fat but i am now 68 kg (175 cm tall). i hope with this new eating i ll obtain some body recomposition and get rid of the central fat gaining some more muscle when i end ketosis and start again low carbs. i reckon i now have a 17% body fat and when it all started i definitely was about 27% and my weight 76/78).

    As i have said i m getting Fasting BS, A1C and insuline checked again in a month but i did checked my lipids profile a month after starting low carb high fat.

    Tryglicerides 40!! (from a previous 150 after coup of months of eating meat again and from a 180 dated back to my vegetarian-vegan two and half years.)
    HDL 45 (think i need to eat more fish??)
    LDL 75

    I m now trying to enter ketosis and i did feel very weak and weird for few days on a <20 grams of carbs a day mostly from raw spinach leaves and tomatoes after 5 days of weakness and lightheaded i have then found out about the need of getting more sodium and electrolites in.. i reckon i was getting into hypovolemia and in fact as soon as i started adding about 3/4 grams of Himalayan salt a day with my meals and takin some extra potassium i felt immediately fine! Today i woke up for the first time with a 75 fasting blood glucose! And i feel sooo good!. I cant describe it… its such a different way of feeling. I feel like i v also slept very well. I feel very rested. My heartrate is slow (55 bpm) and regular and i feel like after i ll be done with this post i ll get to the shore and i ll be swimming in the mediterramean for hours.
    I have ordered the ketones strips but still have to be delivered. (I ll upload results when i can). Was thinking since my blood sugar fell stable for the first time to 75 (with an 80 postprandial!!!) i might now be already producing enough ketones and then be already in ketosis??

    My postprandial has always been well over 130 !! sometimes i had reads of 160 a 20 mins after a meal! my postprandial on a low carb is now around 95 and in ketosis as i v said today i have measured an 80 30 mins after breakfast and an 87 30 mins after lunch!

    Finally i have some considerations/questions:

    1) the lipoma i have on my left shoulder considerably shrank since i have started low carb. Do you think it might be related?

    2) i have had involuntary tic and twitches of my eyes and forehead for the last 13 years i have never managed to sort that out… after seeing doctors, taking herbs, refusing to take benzodiazepines (prescribed by a fool!!!) they are now gone!!! i thought i v had to live with those forever!! They are gone pretty much since i have started low carb and dumped grains!!! Is that because i am probably allergic to gluten and for the leaky gut caused by grains or because i do not have energy spikes? Both? i d love to know what you think about this!!!

    3)when in ketosis the glcycocen in the muscles is used only when needed? as for sprints and anaerobic? or it runs out with daily activities and then muscles stay empty running on fatty acids? can the glycerol byproduct of fat oxidation refill muscles glycogen?

    4)if muscles are not refilled with glycogen means they will never hold much water under ketosis right? how bout if that spare reserve of water is supposed to be there in case of emergency? i mean since ketosis dehydrates you isnt that bad? holding a water tank half full? someone in ketosis would die earlier than someone who s not if stranded on a boat?

    5) do i have to keep taking more sodium and supplementing electrolites as long as i remain in ketosis? or once used to it can i do without? because really as soon as i dont get enough salt i feel awful.

    6)since i m afraid body could use muscle protein for glucose genesis i am taking bcaa pills before bed and whenever i cant eat for a few hours. do they have an effect on insuline? should i keep taking them? also once adapted to ketosis and even on low carb does the body still steal muscle protein when liver is runing out of glycogen or since fat is main fuel it doesnt do that anymore?

    Sorry if my post is huge.. its the first ever for me in regarding nutrition. thanks again man!

    • Andre

      re (3) glycogen is refilled in ketosis, though liver glycogen may be lower, something like 75% i read somewhere
      re (4) I bet the keto-adapted person would live a little bit longer as he is already adapted and can patiently analise his options on his island, while the non-keto adapted goes through some hard initial fasting days, crazy and might kill himself accidentally… until he ends up keto-adapted as well which takes at least some days on a complete fast and weeks on low-carb
      re (5) read phinney and volek low-carb performance books, daily broths should fix it, I got accustomed to a more salty lifestlye and dont supplement although I am always on ketosis
      re (6) if you are not an elite athlete I bet you wouldnt even need bcaa, keto adapted I can fast and not work out a while w/o losing muscle, this is generally not an issue, especially if you do resistance training

    • Nicola


      your experience with a veg* diet has been unpleasant to say the least. Maybe it was not properly implemented, maybe you have some malabsorption, which renders you not compatible with that sort of diet, at least in the way you followed it. Who knows.
      My experience has been radically different. I am 41 and been vegetarian since the age of 17 (for ethical reasons). I have even been vegan for a couple of years in my early 30s, but I had to drop it, because it was getting too much in the way of my social life.
      However, I have always thrived on meet as well as on veggies, diaries and starches. I liked meet, when I was eating it (and a lot, my uncle was a butcher!), but I do perfectly well also without it. I only supplement B12 (Ratiopharm 10mcg/die) and I periodically check my B12 serum level, as well as Homocysteine, they are both fine, and alway have been, since when supplementing.
      I have recently switched onto a LCHF vegetarian diet because I am marathon runner and I wanted to experiment with reducing the RQ ratio and make my marathon running experience overall better.
      I have run a test marathon last Sunday in Karlsruhe, as a training towards my next one in Frankfurt at the end of October, almost equaling my PB of last year. But this time without carbo-loading, 5 Kg less overall weight (mainly water and glycogen, and 1Kg of body fat), never stopping at water station, only drinking 250ml of water and SuperStarch at the 20th Km.
      Just my two cent, with the disclaimer that my body has always worked fine, on many diets regimes I have adopted over the course of my life:

      * [0-17] years – Wild Meat Eater ( lots of meat, especially pork, almost no fish, because I disliked it, but also lots of starches),
      * [17-39] years – “italian” vegetarian diet (yes I am Italian, so typical center-Italy diet, minus the meat, it tends to lean towards the high-carb/low-fat), with 2 years of vegan diet (even more high-carb)
      * [40-41] year – vegetarian high-carb/high-protein/low-fat (with nutrient time-distribution tuned to support my running training)
      – Last 6 weeks – LCHF Ketogenic

      In all cases my blood tests have always been fine (and they have become more and more extensive over the years).

    • LUCA

      Nicola thanks for your post.

      My body apparently doesnt absorb any kind of supplement b12 not even the metyl form of it.. i have tried any way possible with no luck.

      eggs and meat skyrocketed not only my b12 but my energy, my metabolism and anything else.

      carbs (not necessarily grains but even fruits and starches) make me tired, bloated, gassy and depressed. i wish someone would have told me that 30 years ago! i have struggled for over 3 decades with that sort of constant fatigue. if i knew the secret was in fats, animal proteins and fiber from leafy greens i would have implemented that in my life ages ago. still glad i v got there lately… but yeah, grains, starches and vegan diets to me are equal to tragedy.

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  • Max Porter

    How do you handle micro-nutrient deficiency when going through Ketosis? That seems to be my biggest issue. Do you just use multi-vitamins?

    • Which ones? No role for MV. Some sodium, Mg initially. Most people need vit D, but this is diet-independent.

  • Max Porter

    Calcium and Vitamin C are the two that come to mind

    • Max Porter

      Actually just other antioxidants in general. I realized I can get calcium form leafy greens.

      • Correct, and vit C is only required in the most trace amounts when glucose is minimized (this is why Inuit never got scurvy). But the questions to ask are:
        1) Which “antioxidants” are you missing?
        2) What is the evidence eating them is necessary for health?

  • Max Porter

    Point well taken. Thanks for your help Peter!

  • Lily

    What would your advice be to a 63 year old woman who needs to lose at least 100 pounds? Exercise is extremely uncomfortable and actually dangerous at this point. A family doctor has simply recommended weight watchers. Is that really enough? Aside from trying to eat less at each meal, what kind of diet could this individual attempt in order to lose some of the weight so it would be more possible to move more?

    • Hopefully this blog would give her some ideas.

  • Yossi Mandel

    I’ve noticed ?HB called D-?HB or L-?HB in some textbooks and research. Do we call it plain ?HB because it doesn’t matter if the OH is attached on the right side or on the left side for our purposes, for ketosis etc.?

    • Yossi Mandel

      If beta symbol not showing up, that should be BHB, D-BHB and L-BHB.

    • Only relevant from a synthetic chemistry standpoint. The body produces (if I remember correctly), the D isoform.

    • Yossi Mandel

      Wow, impressive memory! Yes, the studies were referring to DBHB as being present in the body, but in some of them they fed synthetic LBHB along with DBHB to rats.

  • Brian

    Peter, love your blog and it has been transformative for me. I came across this article and wanted your opinion. From reading this blog, it appears that: the expermient didn’t last long enough and the complaints were expected; the hdl went up and triglycerides want down, significantly, in LC v reduction in total for other (which is great); the LC was not actually ketotic. Is that accurate? Any other thoughts? I am starting the diet in accordance with this blog (along with Phinney/Volek books) and also starting to train for a marathon. Any help/advice/guidance would be greatly appreciated. Thanks!

    • Two weeks is not nearly enough time to adapt to a major fuel partitioning change. It took me 12 weeks to get over the first hump and exceed aerobic performance, nearly 18 months to exceed previous performance on top end output. In addition, studies like this fail to provide necessary mineral/fat compensation.

  • Gavin

    Hi Peter. Lovely and very interesting blog. As a recently converted LCHF long distance runner, I ran in June my 11th Comrades Marathon (in South Africa), and felt the best ever despite the hottest conditions ever. I was truly converted. I have felt good most of the time out of running as well. Today however I ran a standard marathon in the worst time (almost) ever, in 15 years of running. At km12 I was almost history despite having had a good protein and fat buildup. I had to resort to Coke to get me through. Having listened to your videos I pick up in parts the lack of certain elements, especially sodium. In your experience could this be part of my dilemma and if so is straight forward sea salt the answer? If you could point me in any direction on your blog I would appreciate it, or a short bit of advice would be great.

    • Certainly could be, especially if you’re going very low carb. Mild carb restriction doesn’t seem to require sodium supplementation, but significant restriction unquestionably does.

  • amy

    Hi Peter,
    I have been testing my blood BHB levels and despite strict adherance to less 30 gram carb and 50-60 gram protein, only have been about 0.4 or so in the AM. I have checked a few times at bedtime and have values of 1.5-2.0. My AM blood sugars are 90 ish. Is this a cortisol/dawn phenonmenon? Given that I don’t want to poke myself all day (expense), what time would you suggest as reflective of baseline (as I don’t think that the AM represents that for me). Any input would be welcome. thanks.

    • Hard to know, for me at least, without analyzing dietary records, but it would not surprise me if you’re north of 1 mM most of the day.

  • Vinnie Santana

    Hi Peter and readers,

    Appreciate the information you are putting in here, please keep up this breaking through work.

    We touched base about a year ago when I was shifting into a Ketogenic diet, T1D and former pro ironman athlete, am still on it and had great results on my health and managed to combine with short course triathlont raining. Wrote a blog about the experience here:

    Talk soon,
    Vinnie Santana

  • calvin

    Hi Peter

    I keep reading your posts. I like your scientific stance and insights.

    My question is far less technical than most of the ones I have read here. I am on VLC since about 6 months, and happy like that for the moment. I do not measure ketones every day, but I know that if I am careful with proteins I consistently measure over 1 mM in the morning. So no troubles keeping a ketotic state, with the exception of … how to call them … social difficulties. In other words, what do you do when invited for dinner by friends? This is not something you can carefully plan, as you can do with a birthday, and I find it a bit anti-social to refuse eating what people have carefully cooked for me, or to impose them restrictions on what they cook or eat. Same applies when I travel: it is not always easy to keep a proper keto diet when far from your usual supplies or when you have no possibilities to cook for yourself; to say a couple of places where it is not that easy to stay on a high fat low carb regime, try in Italy or in Japan; you cannot keep eating nuts day after day.

    One comment. I see that questions like “what is the recipe of your xyz dish?” are not unusual. Why don’t you open a section for keto-compatible recipies? By that I mean a place in your blog where your and other people can post recipes – of course only if validated by a proper BHB measurement.

    • Very personal decision, Calvin, and no “right” answer. It’s such an important topic, though, that it probably deserves a post of its own one day. As to your last point…I just don’t have the time or inclination to start a cookbook, also.

    • calvin

      hi Peter

      your point seems to be: until this eating style becomes widespread, it is up to the individual to find a compromise. Maybe one day eating low-carb-high-fat will be accepted like vegetarianism is. Or maybe not, who knows.

      Anyway, I gave a shot at your suggestion. I have no idea of my VO2max, or of my RQ at a specific HR, so I had no quantitative base to start from. Still, by doing some intense intervals in the morning, then having 50g pasta during lunch (which adds on top of my usual ~ 50g of daily carbs) I observed ketons down to 0.8mM about 2h after lunch (not dramatic, I guess) and the usual >1mM the next morning. So … test passed. And the good thing is that I could liberally add olive oil, nothing more and nothing less than what my palate wanted, without feeling guilty for not eating “healthy”.

      On the base of all this, what is shown in this post (muscles in “refusal mode” for glucose when in ketosis) seems contradictory with what I see here … Am I wrong?

      • It think there may be 2 things going on. One (and it’s been a while since I read this post), I think Peter was only referring to FBG, not a “glucose challenge” which is what you describe. Second, this is always complicated by glycogen debt. When my glycogen debt is large, my glucose will go down after even 30 gm of CHO. I actually observed this yesterday. Glucose was 75 (about 4 mM) 2 hours post meal.

  • SusanneL

    Hi Peter.

    I have a question I wonder if you know anything about. Sometimes I take 5-htp (in the body converted to serotonin) due to help me with stressful times and also cause I find that it helps me to get my bowel work better. To balance the hormone system i would also from time to time take L-tyrosine (in the body converted to dopamin) Now it seems that when I take tyrosine it seems that I get “cravings” and feel more hungry and eager to eat carbs. It is to my knowledge a fact that dopamine is a “kick” hormone for the body ie when you eat, have sex, train and so on the body produces dopamine. But can dopamine “work the other way around” in such a way that my cravings of carbs can be caused by intake of my tyrosine pills (and thereby increase the dopamine)?

    • Interesting. It certainly seems plausible given that we know SSRIs can be activating or sedating and impact appetite (up or down).

    • SusanneL


      Did a little research at our swedish “Fass” (site with listed medicin) and found out that a medicin called “Voxra” from GlaxoSmithKline, containing “Bupropion” (given to people with depression because of inbalance of dopamine and noradrelanine) should not be used by people with alcoholproblems or with eating disorders such like anorexia or bulimia. So it seems that I’m sensitive of dopamine and I will sure stop to take L-tyrosine (seems so harmless cause it’s just aminoacids though). I will instead get my “kicks” of life itself and training as usual! 🙂

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  • Guido Vogel

    Hi Peter,

    I am actuallly struggling with a pretty basic question. If we don’t need any dietary carbohydrates for survival, why are most of us so fond of them? Especially the high glycemic ones. They make us fat easily, but what (evolutionary) purpose does that serve?

    East-Africa is not known of for their harsh winters, we don’t go into hibernation. Was lack of animal fat/protein a sign of (upcoming) starvation, so the carbs are converted to fat as soon as possible?

    There must be fundamental reasons to eat the stuff that makes us fat and ill.

    Any thoughts (or a good reference) on this?

    [Aside: Gary Taubes’ book is called “Why we get fat”, but a better title would be “How we get fat” is the why question isn’t really addressed]

    • That’s a good question, Guido. I can discuss this topic of hours, and often do, with friends over dinner. I would offer two thoughts:
      1. Just because we are fond of something, does not imply we are better off consuming it to our heart’s content. Remove the social stigma from heroin and people are pretty fond of it when they’ve had a taste. Is it good for us? Unlikely.
      2. We evolved in a pretty food-scarce environment, so evolutionary pressure was going to favor an affinity for foods that enable us to store energy better (e.g., fructose).

    • TS

      That certainly is an interesting question, but I reject your premise as a clear oversimplification. If my objective were to fatten someone, I would not attempt to feed them lean potatoes, instead I would resort to making mashed potatoes that are 2/3 potato and 1/3 butter — not just for the resulting increase in energy density, but also the heightened (hyper-)palatability. Even a carbohydrate source that is filled with sugar such as most fruit, which some people describe having an opioid-like effect on the brain, can be hard to consume in excess on it’s own — certainly consuming the fruit as liquid calories, in the form of juice would make that easier, although I don’t believe by as much as you might think.

      At the moment I need roughly 2000 kcal per day for energy, plus some protein. Four liters of orange juice has about 1800 kcal. Considering that sugar is known to boost the metabolic rate, I think around five liters of orange juice per day (if not more) as a sole energy source would be needed for me. I’ve never even imagined the possibility of drinking that much juice in a day. It just seems unreal.

      Also, something else I’d note is that we do not need any dietary fat either for “survival” per se. There is the subject of essential fatty acid deficiency, though I believe it would be pretty unrealistic for this to occur naturally. On top of that (perhaps I’m ignorant, but) as far I can tell the research on laboratory induced EFA deficiency is very lacking.

      I think the two of us are alike (as are most of the people reading this blog probably) in that were fascinated by thoughts and ideas that do not lead to a clear answer, and as such can be strongly debated and interpreted from multiple viewpoints. If something appears to not be logical or rational at first, it can be especially easy to get attached to the basic concept of the first hypothesis that seemingly makes sense of it all (in that it makes overarching sense perhaps only because one doesn’t know enough details at that time to think otherwise). It’s important to not get stuck in a certain mindset and forcing all new discoveries onto a certain framework (research bias). Very often I’ve tried things that seemed likely to not be optimal just because I wanted to find out exactly what the result would be.

      That said, as it relates to diet, for the average person I think it’s often best to avoid a lot of the anti-sugar dogma, as much as the dwindling low-fat dogma. Let’s say someone were to find that every time they eat a sweet fruit they get an impulse to over-consume calories, possibly they should just eat a lot of fruit at that meal and not much else, or alternatively avoid anything sweet altogether. There’s no clear homogeneous answer, so it’s not worthwhile to attempt to simplify it to that. It would be a matter of tinkering and finding what works for them, all things considered.

      • So this is the price I pay for going against my better judgement and giving an over-simplified response to a complex question. I’ll reserve a response for a time when I can actually dig into it. TS, if you’re interested in what is probably the best thinking I’ve seen on the role a uricase mutation played in our evolution take a look at the paper: Evolutionary Anthropology 19:250-257(2010) by Johnson and Andrews.
        And I certainly agree that combining fat with CHO makes it even more palatable (and possibly addictive). Your example is a great one, but ice cream may be the best.
        Lastly, show me someone who has gone one year without a gram of dietary fat. I’m willing to guess they will not be well.

    • TS

      Peter, my comment (including the part about oversimplification) was directed at Guido. The way I interpreted his comment was it being unreasonably anti-carb, although now I realize that it’s more likely he just wanted to get his questions across without spending unnecessary time on fine nuances.
      Worst case I came off as ignorant and opinionated — certainly not something I aspire to be.
      I can’t bring my self to re-read my previous comment because I fear a lot of it is unintelligible ramble, but part of what I wrote earlier regarding EFAs is surely incorrect. It was based on the observance that “EFA deficiency” is often another way of saying “mead acid production”, and I simply don’t know if that’s mutually exclusive with being “healthy”. Also, to the best of my knowledge in the case of a DHA deficiency, the body can convert ARA into docosapentaenoic acid as a partial replacement. And that in the case of an ARA deficiency, the body can synthesize mead acid from oleate as a replacement.

      Have a nice day, guys.

      • Well, my response was also a bit a simplification, but thanks for clarification.

  • Guido Vogel

    “1. Just because we are fond of something, does not imply we are better off consuming it to our heart’s content. Remove the social stigma from heroin and people are pretty fond of it when they’ve had a taste. Is it good for us? Unlikely.”

    No, but addiction must have some roots in evolution. Dopamine is important for feeling well. Is heroin an example of overstimulation of the natural system of feeling well (dopamine regulation)? The same might hold true for high glycemic carbs. “Unnatural” products create a runaway system.

    “2. We evolved in a pretty food-scarce environment, so evolutionary pressure was going to favor an affinity for foods that enable us to store energy better (e.g., fructose).”

    Do you have any good source to find out what the climate was like in East-Africa 200.000 tears ago?
    If indeed the carbs were a sign of lack of food, the combined effects of 1&2 might work as a double edged sword to maximize fat accumulation eating high glycemic carbs.

  • Andrea Nist

    I have read your website for hours and hours but need help on where/how to start. My daughter is 19, a division I college runner (6k), and has become unhealthy the last year. She gained 10 lbs, is now insulin resistant, has high cholesterol (240), high triglycerides (131), LDL (151), HDL (69). She has been gluten free, dairy free, sugar free since May. No improvements. Her BMR in May was 1890. She fluctuates her calories between 1600 and 2000. She is currently red-shirting this cross country season but we need help. We have seen so many docs. One doctor prescribed D-Ribose. Is this safe when trying to cut out sugar? She has two weeks off from running in Nov. Is this enough time to adjust to NK?

  • Andrew Gehring

    First off, your website is an absolutely fantastic resource and you’ve done some incredibly interesting work that supports ketosis as a potential way to treat diabetes, metabolic syndrome, cancer and enhance athletic performance. I think I recall you mentioning an interest in the administration of exogenous ketone bodies as a way to bypass the fairly extreme dietary changes needed to achieve sustained dietary ketosis. I was wondering what your opinion was on the use of activators of AMPK to increase fatty acid oxidation, resulting in an increase in circulating ketone body levels. I would think that AMPK activators would help an individual transition from a physiological state that relies on glucose to one of ketosis by helping to mobilize fatty acids for catabolism. For example, if someone is transitioning to a ketogenic diet exercise (naturally activates AMPK) with exogenous AMPK activators might make it easier for the body to access its fat stores and allow them to achieve ketosis more quickly. I wouldn’t think an activator of AMPK like Metformin would work particularly well, given that it is not a direct activator of AMPK and inhibits the ETC, but I would think something like salicylate (a metabolite of acetylsalicylic acid that activates AMPK directly) might work well in augmenting the body’s ability to transition to ketosis. I’m just curious to hear what your opinion is on this matter. Thanks!

    • It has been proposed, as you note, that AMP kinase activation (partially) explains the efficacy of metformin and some of the purported anti-cancer benefits. It may also explain why fructose in excess can be harmful for susceptible folks (the opposite effect). Exogenous ketones, of course, bypass the entire system.

  • Bruce Evry

    One has to wonder if Metformin may be beneficial because Cancer is yet just another aspect of diabetes? Seems that Cancer is yet another problem with sugar metabolism and insulin response (like so many other issues). Perhaps if we all stopped eating quite so many carbs we’d see a noticeable decrease in cancer, diabetes, etc.

    • As you may know, patients with T2D who take metformin have better cancer outcomes than matched T2D who do not. Proves nothing, but worthy of investigation.

  • Kyle Norman

    Dr. Attia,

    I’ve recently discovered the ketogenic diet and I’m fascinated by it (I’ve also read Phinney & Volek’s work.) I’ve been trying to get into ketosis (as monitored by the Abbot blood monitor) and I seem to be missing it. Here’s my simple question: Can too much protein consumption keep me out of ketosis?

    I imagine that has been asked and answered elsewhere so my apologies for asking again. I don’t recall if I’ve read anything on the issue, but perhaps Phinney/Volek have explained it. Thanks

    Kyle Norman

  • Sethy

    Hi Peter,

    Apologies if you have already covered this but do you have any recommendations on Blood Monitoring kits?


  • Peter

    Hi Peter,

    Just achieved Ketosis (and feeling GOOD) according to Ketostix and also just purchased the precision xtra. I have been active and athletic my entire life and continue to ride and swim but unable to run due to back issues but am very healthy otherwise. Over the last ten years I have crept up 20 pounds mostly around my waist, I am now 54 and hope to continue working out at for as long as possible. Should I expect any age related complications in my performance, fat loss and/or nutritional ketosis state? Also when do we need to worry about ketoacidosis?

    You’ve become a long needed inspiration!

    • If you don’t have type 1 diabetes, no need to worry about DKA. Addressed in great detail elsewhere on blog.

  • Hi Dr. Attia,

    Congratulations for your blog. I just discovered your website and I am FASCINATED by the quantity and quality of all the information you provide. Last year I was on the keto diet for a month and lost about 20 pounds, now I have started again and I am on my 17th day, feeling great, with reduced appetite and with one question. I have read that coffee increases insulin production, does this happen even if there are less than 20 gramms of carbs in my diet? I only drink a cup of coffee in the morning with a tbs of coconut oil. Maybe the answer is somewhere in the blog, but I have not read it all yet.

    Thanks a lot!


    • Caffeine may alter insulin sensitivity, but it’s not clear how large the impact is.

  • Isobelle

    Hi doctor, I’ve searched for information on medium chain triglycerides but couldn’t find it and I know that you have discussed it somewhere. Can you guide me to any of your discussions on the subject? I am interested in the fact that coconut oil is being used for the treatment of Alzheimers. Thanks.

    • I have not written “formally” about MCT, but have referenced them in different places throughout the blog and comment. Lots on line, also.

  • Karen

    Excellent information! We are just starting out from a very sedentary lifestyle to working out (strength and cardio) an my husband was freaking out that he gained weight the first few days, and lost to net zero/no loss for the week – first time since July 1st he didn’t lose weight in a week. With my strength training routine I notice I do gain weight, although it balances it out through the week. As long as I’m still losing inches I don’t mind as much! Valuable information, here, thank you!

  • Allen W.

    Dear Dr. Attia,

    I have a somewhat strange question about nutritional ketosis. A week ago I took the plunge and forced my body to switch over into nutritional ketosis. Here is the weird part, since I was a teenager 30 years ago I have known that dark urine means I am becoming dehydrated and I need to drink more water. Normally when I get up in the morning I will do my business and my urine would be relatively dark despite the fact that I frequently would drink a glass of water close to bed time. Sunday morning I realized my urine was quite light in color but did not think to much of it, however I also realized I do not get nearly as thirsty when working out on the elliptical machine as I was for the past year and I am drinking less water while working out. I tried researching online to see if metabolic water could be having such a large effect but did not find any studies or even anecdotal reporting on the subject. I don’t know of any reason why unusually light colored urine would be unhealthy, but I am not a medical doctor and do not know what to make of this change in my kidney function, or even if it is a change in my kidney function. When I tried to work out Saturday it was a terrible slog and I gave up after 20 minutes but today I worked out for 70 minutes and felt as if I could have gone on much longer if I had wanted too. Even so I drank no water while working out today, I only perspired lightly (we keep the heat low in the winter so the house was 62 degrees F for my workout) and after the workout I used the restroom and again my urine was very pale in color. I know you don’t give medical advice over the internet, but is this something I need to make an appointment with my General Practitioner about?

    Thank you for all you do, if not for your inspirational work I would never have been brave enough to take the step from no sugar to low carb to nutritional ketosis from late January 2013 to last week when I committed myself to 28 days of nutritional ketosis.

    Allen W.

    • Hard to say, Allen. It turns out urine color is not (despite what seems obvious) a reliable indicator of hydration status. A urine specific gravity is much better. So if you have concern, best to see your doctor.

  • Chee Fong

    Dear Dr Attia

    I know you are a busy man, so I will try to keep this as short as possible. I must say right off the bat, that I am not like the average reader of your blog, who are admirably intelligent, so please forgive any statement that reeks of ignorance. I would like to draw attention to Advanced Glycation End-products (AGEs). I first came across AGEs in Dr William Davis’ ‘Wheat Belly’ book. They are said to cause anything from atherosclerosis to dementia. They are essentially useless debris that result in tissue decay as they accumulate in our body, purportedly contributing to the aging process and are perhaps a major cause of diabetic complications (neuropathy etc.). They are also found in much higher amounts in older people. AGEs are also a by-product of high blood sugar. To better describe AGEs, I would like to quote an excerpt from ‘Wheat Belly’ : “The greater availability of glucose to the body’s tissues permits the glucose molecule to react with any protein, creating a combined glucose-protein molecule. Chemists talk of complex reactive products such as Amadori products and Schiff intermediates, all yielding a group of glucose-protein combinations that are collectively called AGEs. Once AGEs form, they are irreversible and cannot be undone. They also collect in chains of molecules, forming AGE polymers that are especially disruptive.2 AGEs are notorious for accumulating right where they sit, forming clumps of useless debris resistant to any of the body’s digestive or cleansing processes.” INTERESTINGLY, AGEs are also found in high quantities in animal products (meat and fats). Here is a paper about AGEs and their content in various food, So I wonder, if a diet like yours, which is high in saturated fats, may also yield a high AGEs content. Bacon, especially, is extremely high in AGEs. High temperature cooking methods also dramatically increase the AGEs content in food. I also practise a diet similar to yours, which is LCHF. I worry that, such a diet may have the unexpected disadvantage of coming with a high AGE content, and may thus increase the risk of atherosclerosis (and other complications). May I suggest that you take AGEs into consideration in your NuSi efforts ? What is your take on this ? Sorry for the lengthy post and thank you for your time.

    P.S. You are a great inspiration, it takes tremendous courage to admit one is wrong and go against the prevailing dogma and carry out self-experimentation. If only we have more people like you in the medical profession.

  • Joe

    Hi Peter,

    Thanks for all the time and passion you put into this over the years. Over the past few months I have successfully lost 35+ lbs (28 fat) through NK. After studying much of your blog I am now adjusting further by increasing my fat intake and lowering my proteins. Question: I have a hunch that human ketones (acetone, acetoacetic acid) are not chemically the same as raspberry ketones (C10 H12 O2). If one were to ingest true, pure raspberry ketones (C10 H12 O2) would that provide any physiological benefits identical to human ketones? (I was considering an experiment by using raspberry ketones for the 2 days following cheat days to try to maintain my ketone level and responses while my body adjusts down from the carbs of a cheat day).

    Joe Richardson

    • Raspberry ketones are really just a gimmick. If aspiring for NK, berries are fine, but need to be kept in modest doses.

  • Staying in nutritional ketosis is sometimes counterintuitive. Using the calculator on the above website which give the ketogenic ratio for example, If a person went over in carbohydrate and to a lesser extent protein they could still stay ketotic if they compensated with more fat. Even though this would be much higher in calories they would stay in nutritional ketosis. The ratio correlates strongly with the blood ketones.

  • Norm

    In an attempt to get into ketosis many people have experienced pounding heart especially at night.
    Why this could be? Thyroid? Electrolytes? And how to tackle it?

    • Impossible to say without a workup, Norm. That’s why I can’t practice medicine via a blog.

  • Norm

    That’s true Peter. On the other hand what people like yourself are doing on blogs is way better than what many doctors are doing in practice. Like increase in LDL-C on a low carb diet, pounding heart issue also seems quite puzzling for some people, especially when adding carbs back seems to fix the problem in both cases for many people but they are kicked out of ketosis and stop losing weight. Some have reported to have fixed heart pounding by adding sodium also. Not sure if one can supplement more than 2-3 grams of sodium if this much does not work?

    • Magnesium helps with potassium, also, which is often the problem.

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  • Norm
  • Nonna

    You mention a metabolic response to inflammation as a result of exercise and refer another commenter to systemic inflammatory response syndrome. I searched your web site and your Coming Soon page and didn’t find anything regarding the metabolic response to infection or inflammation. Thus my question: can an infection knock one out of ketosis — cause the BK to drop down to 0.2 and the BG to remain higher than baseline — and for a person to gain weight, even when adhering to a LCHF diet?


    • Nonna

      I meant to say — gain weight that is not just water weight, but weight around the waistline. And in rereading your post and some of the comments I’m thinking that the SIRS response to inflammation from exercise is not much different from a metabolic response to infection? Just would like it see it all fleshed out in a future blog post. Plus maybe the implications are that when one is having an SIRS response to infection, perhaps it’s important to introduce some carbohydrates in the diet just as athletes do in their glycogen recovery phase?

      Sorry if my questions are garbled.

    • Nonna

      Sorry to be a serial commenter! I need to continue to clarify: when I’m talking being kicked out of ketosis and gaining weight due to infection, I don’t mean a transient experience but rather one lasting 2 -3 weeks. Also I researching metabolic responses to infection I stumbled on the following article from 1981 and don’t have the training or background to interpret it fully. It does seem to be a somewhat different process than what’s described in the wiki for SIRS. It suggests that there are two parallel responses to infection — immune and metabolic:
      The American Society for Clinical Nutrition, Inc
      Effect of diet on the metabolic response to infection: protein-sparing
      modified fast plus 100 grams glucose and yellow fever immunization.
      B R Bistrian, D T George, G L Blackburn, and R W Wannemacher


      The metabolic response to yellow fever immunization was investigated
      in four obese subjects who were consuming a protein-sparing modified
      fast plus 100 g glucose (PSMF + 100 g) for 3 wk. Fasting, 1/2, 1, and
      2 h postprandial values for insulin, glucagon, glucose, lactate, beta
      hydroxybutyrate, acetoacetate, and free fatty acids were assessed
      before and the 1st, 3rd, and 5th day postimmunization. The hormone and
      substrate response to dietary protein plus glucose was a substantial
      rise in insulin (p less than 0.005), glucose (p less than 0.005), and
      fall in free fatty acid and ketone levels (p less than 0.005). These
      results are distinctly different from the response to dietary protein
      ingestion only (PSMF) determined in a previous study which was a
      slight rise in insulin and glucose and slight fall in ketone bodies,
      but a substantial rise in glucagon. The only significant (p less than
      0.05) change following immunization in the PSMF + 100 g was a rise in
      serum glucagon on day 1. During the PSMF significant elevations in
      insulin and lactate and falls in serum ketones were noted
      postimmunization. The metabolic response to mild infection is
      dependent on the diet consumed. These differences may have a clinical
      impact when the infection is severe, but this possibly requires study
      in an experimental infection of greater severity.

    • Yes, infection can easily cause an adrenal response, which increases hepatic glucose output, which can knock you out of ketosis. A server enough infection causes a SIRS response, which almost invariable leads to weight gain — virtually all of it being third-space (interstitial) water weight.

  • Dr. Attia,
    Your information is invaluable! I had a question and I’m not sure is the right blog post but here goes. I’ve been paleo for 4 years and 6weeks ago started a keto program. I’ve noticed that my blood glucose is around 65 at any give time of the day and my blood ketones vary from 0.1-0.4 and urine ketones are not present. . I’m not sure what my body is using for fuel. I lift weights around 1-2 me a week and do Jujitsu 1-2 times a week. Can you shed some light n what my body is using as its main substrate for fuel?

  • Marko Skoric

    Dr. Attia,

    I wanted to know your opinions about my training regimen. I would really appreciate your advice.

    I am a 25 years old male from Croatia and used to be a professional tennis player. Until 5 years ago, I trained 6 hours a day and my diet was of course mainly comprised of carbohydrates. It was three huge meals consisting of either cereals with milk, pastas or pizzas. Five years ago I moved to the States when I was offered an athletic scholarship to play for a university. I moved to the States and played there for three years.

    Two years ago I stopped playing tennis all together to focus on studying and went from 86kgs (which is my playing weight), to 100kgs. I kept the same diet as in my competitive days, and I think that the processed foods from the US didn’t help. I became depressed, brain fogged and was always hungry.

    My thirst for nutrition knowledge started after I read about the “Steak and eggs” diet. After a year of going strict keto (except sometimes weekend carb reloads) and lifting heavy weights, I am back to a comfortable 90kgs. I eat a huge meal in the evening and fast for pretty much 20-22 hours each day without a drop of energy. I eat lots of eggs cooked in butter or lard, red meat and some vegetables on the side. I can lift fasted without any problems but don’t think I will be able to keep this diet when I start playing tennis again this summer. I am happy to have regained metabolic flexibility but would like to incorporate carbs in my tennis regimen and keep fat burning to a maximum.

    I wanted to know your opinion about using boiled potatoes (because of high satiety index) as my only source of carbs during tennis practices (might it be enough for the sweating of minerals)?
    Would it be optimal to start playing fasted and then eat them during practice or eat them before practice ?
    Also, would you think coconut oil would be a good enough source of energy during practice under hot conditions?


    Marko Skoric

  • Brent Rice

    Hello Peter-

    I have been incredibly successful in achieving some goals through reliance on your information from your blogs. Last week I took 2-3 days and gorged for Christmas. You name it, I ate it. In the past I would occasionally allow myself a sushi roll or something along those lines as a rare treat and be back in mitosis in a matter of hours to half day at most. After my Christmas splurge I was out for almost two days. Even now that I’m back in, it seems very intermittent. The only change has been glutamine, creatine and BCAA supplementation. The brand is prosource so I’m probably imbibing bird feathers from what I have read here, but I’m wondering if you have seen these supplements cause problems with staying in mitosis before. I do about five grams of BCAA during exercise and again after. Glutamine is five grams after, creatine is five grams during and five after.

    My results are probably all the answer I need but I’d like to understand why one or more of these may be causing me problems.

    Thanks in advance,


    • Brent Rice

      Excuse the auto-correct – I did not mean cell division but ketosis.

    • Brent, I assume you mean ketosis and not mitosis (damn auto-correct, I suspect). This experience is pretty typical. Should resolve within a week or so. One way to speed up the process is a very long sub-threshold effort with a few glycogen-depleting efforts.

  • Eric

    Hello Peter,

    Is it worth testing blood sugar?

    I have never used a sugar testing strip for the meter I have – just the ketone ones.

    I’m currently using your standard of shooting for > 1 mmol ketones after overnight fast but am wondering if and how you use sugar measurement to help dial in your ketogenic diet.


    • It ads some insights, but I’m not sure it’s necessary. It’s much cheaper than testing BHB, so I always do both together. I like seeing the relationship.

  • Anthony

    Dr Attia,

    Watched many of your videos and read many a book on Ketosis for athletes. I am 50 years old and still play competitive ice hockey. I I weight train 3x/week. Stats” 69″ and 230lbs (LBM=176). I cannot sustain my favorite sport on 50G CHO /day. I opted to carb backload and it seems to work for hockey, but I cannot drop the 30lbs of bodyfat I would like. Hearing you lost 40lbs is inspiring. I believe I can replicate that feat.
    Just tested Cholesterol’s and Doctor is worried: Total = 251 HDL = 56 Trig = 69 LDL = 189 Non HDL = 195…
    I am trying to figure out if I am in danger here. Trig are low…but the other numbers are worrisome. Your thoughts on the NKD lifestyle and cholesterol would be appreciated.
    Would be nice if we could find Doctors in our area that are similar in conviction to you! Let’s get that going and we can impact millions.

  • adrian


    I am a runner in ketosis and I would like to know more about this 50gm ceiling for carbs. I have seen it mentioned in many articles and books, but would like your personal view on whether there is reason to lift this theoretical max after heavy exercise. You have mentioned in another article how you can ‘afford’ an extra does of carbs for your daughters wish of eating Indian by incorporating some high intensity exercise. Can this idea be reversed, such that the body will recover better after the high intensity(or endurance) event by ingesting more carbs? If so, is there are hard and fast rule I can apply to my training, or is everyone different.

    I am only new to ketosis, but my own observation levels is that my ketosis level seems to be influenced heavily by exercise. I am have a higher level of ketones the day after heavy exercise. A day of rest produces a lower result.

    Are their any benefits that you know of to lift the amount of carbs you consume after a heavy dose of exercise. Ideally low glycemic carbs at that. I am not suffering in any way from the reduced carb intake (after my initial 2 weeks), only interested in maximizing my performance.


  • Chip

    I am thoroughly appreciative of all your work. Your value to us simply cannot be overstated. Thank you. Thank you, Thank you. It is frightening to know how easily rigorously applied science can be overshadowed by headlines/studies like these. From The Lancet, no less!


    • I usually (but not always) stop when I see the word “meta-analysis.”

    • Boundless

      > It is frightening to know how easily rigorously applied
      > science can be overshadowed by headlines/studies like these.

      Here’s a proposed trial that is either designed to produce no
      meaningful results, or had its protocols sabotaged along the way.

      They plan to equalize caloric intake and glycemic load
      between the non-grain/non-dairy subjects and the controls,
      and will only know for sure what they ate at lunch.

      Real trials by NUSI are clearly needed.

    • Boundless

      > It is frightening to know how easily rigorously applied
      > science can be overshadowed by headlines/studies like these.

      And even when what passes for most nutritional science trips over a significant truth, they pick themselves up, shrug it off, and re-focus on the dogma.

      “The Role of Persistent Organic Pollutants in the Worldwide Epidemic of Type 2 Diabetes Mellitus and the Possible Connection to Farmed Atlantic Salmon (Salmo salar)”

      This study accidentally managed to avoid glycemic confounding, by including 692 Greenland Inuit, who are likely on a very low carb, possibly ketogenic diet.

      Quote from paper:
      “More work is required to better understand why such high levels of POPs were not associated with increased risk of T2DM in this population.”

      The Summary makes no mention of the possibility of diet having a potentially substantial effect on health risks, and of course, shows no awareness that T2DM isn’t really a ‘disease’ at all, but just a predictable metabolic response to a full-time glycemic diet.

      • Boundless, I really like your last sentence. Very nice insight. Wish more thought of it this way.

    • Boundless

      > Very nice insight. Wish more thought of it this way.

      Well, thanks, but it’s shocking to think that I’m so leading edge on that. I’m just an ordinary (non-medical) citizen who has been casually connecting dots since reading Wheat Belly in 2011. What it all leads to seems evident to me.

      For what it’s worth, those two links I posted above were not the result of broad deep digging. They were just two things that popped up lately whilst I was looking for something else.

      This suggests to me, that the issues I raised (1. flawed designs and 2. general obliviousness to blaring klaxons in the data) are depressingly common in current nutrition science. This has to be discouraging to the few enlightened physicians, such as yourself, who actually read nutrition papers.

      Thanks for a very valuable web site.

  • cmztrav

    Dear Dr. Attia,
    Thank you so much for all of the fantastic information you have launched into the ether. You are a gem!
    Right now I am training for an Ironman in July. (I am out of shape and working my butt off). I would really appreciate your advice to a beginner regarding workout vs. race-day fueling. I superstitiously feel that I should simply live my LCHF life during training, but wonder if I should add something on my Ironman day?
    I guess I would like to hear your view about how various carb-based supplements/foods will affect the ability to burn fat during an endurance event. Thank you!!!

    • cmztrav

      Please forgive my laziness, Dr. Attia. If I could choose a full-time job of researching and encapsulating your fantastic work I would. I have gathered your advice from a video of perhaps using a slow-release glucose source for activities lasting over about 3 hours, with some salty nuts and BCAA’s. The farther my workouts progress, the greater the confidence I have in what I am doing. I know nuts work great for me and I will look into incorporating the other two items and see how it goes. I know I feel amazing in ketosis and I thank you and other info-maniacs for pioneering this field.

      I test and log my bhob’s twice a day unless I am running an even keel, so I am learning a lot as I go along. I love your approach and admire you personally for all that you are achieving. Thank you!

  • Mihail

    Hi Peter,
    In case I do a high fat, low carb diet but I just can’t get to ketosis for I don’t know which reason is it a dangerous think? I mean could cholesterol level raise dangerously because my body is not adapted to ketosis? Is it worse then a normal diet, high carb low fat?
    I know HFLC in ketosis is very good but I am nut sure how is it in this area.
    Thank you.

  • Paul

    Hi Peter,
    Amazing info available on this site. Thank you
    I have a question or would like your opinion on my eating/nutrition for an eight day mtb stage race I will be taking part in. (The cape epic). I have been on the high fat low carb diet for 9 months now. I have been training for t)his event since November and have done all my training on no carbs only water on the bike. Many training rides over 6 hours, two to three days in a row. We now getting to the high intensity training phase. The question I have is do you think we can ride for 8 days with only a small amount of carbs after the day on the bike as per our normal high fat low carb diet. Or do we need to eat carbs on the bike? Have been fine up to now but not sure how the body will cope after 8 days.

    Your opinion would be really appreciated

  • Diane Stibbard

    Hello Peter
    I am a highly competitive female athlete, considering the low carb and high fat lifestyle for performance and health reasons. I am gluten and dairy free, and also recently grain free. I do not eat red meat however, but do eat all fish, eggs, chicken and turkey. I am very lean and have practically not body fat. I am 5’1 and weight 95lbs and have less than 10% body fat. My naturapath, who works with high level athletes, is a little unsure if this is right for me, I think more because he doesn’t have any experience with the diet and lifestyle. I think he has concerns about a female following this and also I am prone to adrenal fatigue. However, the adrenal fatigue has been due to not just the physical stress I put on my body, but I have a lot of emotional stress at these times in my life when I fell to adrenal fatigue.
    Please let me know what you think

    • Diane, impossible for me know without long diagnostic and some trial and error.

  • Braz

    It is absolutely awesome to find such a rigorous report on sport performance on a ketogenic state. I haven’t been doing a lot of aerobics lately and have been trying a not very strict (very much “follow your instincts” when eating) sort of warrior diet. I adored the eating flexibility it gives me and definitively want to stick to any pattern of eating that allows me to have the same freedom. I had been wondering, though, i’ld have to drop this idea when getting back to aerobicks. It’s a joy not only to now it is possible and has serious advantages, but also to have serious literature to instruct me. Keep on!

    Btw, any recommendations on warrior diet style reads? People who are for it seem to get something right, but the litterature on it is a disaster.

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  • Fascinating.

    Here in Japan, perhaps partly due to the Japanese love of rice, we are still encouraged to eat 60% of calories in carbohydrates, and everything is low fat and low carbohydrate. The low carbohydrate diet is partly due to the fact that the Japanese did not traditionally eat much dairy, and many do not have the enzyme to processes lactose. Nutrional advice (e.g. from the Japanese body weight scales manufacturer, Tanita) seems to suggest boiling meats, never using butter, no deep fried, and cutting fats out of the diet completely. While the Japanese are really into healthy living, I can find not one single book in Japanese on low carbohydrate diet. Taubes books do not seem to be translated and there are only two books on the Paleo diet.

    All the same though if you look at “maps of globesity” (Google) it seems that everywhere is fat except East Asia, despite these being “the rice economies,” and that the Chinese eat quite a lot of calories often in the form of rice. The Japanese are fearsomely thin. Is this something to do with rice vs wheat & corn carbohydrates, I wonder.

    When are you going to write a book? What are you book recommendations? I’d like to translate it/them into Japanese.

    • Another thing about the Japanese is that they have a very popular “theory of Japaneseness” (nihonjinron) which has it that Japanese culture is agriculturalists whereas Westerner culture is influenced by that of hunter-gatherers. Absolute duff in my opinion, but the Japanese word for “hunter (gatherer)” is closely associated with Westerner, Western food, and ill-health (since after all, as the Japanese know, Westerners are so much fatter).

      So it is no wonder that the paleo diet book did not sell well since it seems, from Japanese eyes, to be selling Western (hunter-gatherer) (ill-) health advice. It says on the front cover “In hunter-gatherer societies no one was fat.” I can imagine Japanese reading that and rolling their eyes.

      The truth may be the reverse, that in fact that Japanese used to eat little rice till recently (it was used to pay taxes, but the common people rarely ate it) and did in fact enjoy a lot of fish and meats. They are the hunter (fisher) gatherers and we are the corn-starch stuffed agriculturalists.

    • No plan to write a book soon. Surprised others haven’t been translated, though.

  • Kieran


    Been following your blog for a few months now and 10 days ago finally took the leap into Keto. Two days back I just received my glucose/ketone meter and have done some readings (a lot less painful than I was expecting, btw!)

    Anyway, what’s interesting me is both days (yesterday and today: testing both morning and night) all Ketone readings thus far are between 1.2 mmol/L & 1.6 mmol/L.

    From reading your blog, these numbers seem abnormally high for someone doing Keto for such a short period of time (10 days) — with that kind of reading, am I technically in NK already, so soon? You seem to suggest it typically takes 4-6 weeks to achieve NK, yet my blood results after 10 days say otherwise. Just curious on your take on that!

    Thanks for the killer content,

    • Nothing abnormal about these. The 4-6 week part is some measure of physiologic adaptation.

  • Carl

    Hit this yesterday after a 6 hour tramp with zero carbohydrates and large amounts of MCT.

    What are your views on using MCT as a ‘catalyst’ into NK, I have noticed some days in the morning I will be around 1.5 but I can bump it up to high 2’s just from having two lots of 30grams of MCT oil.

    How accurate are the ketone strips on the precision? I notice that the glucose can have quite a large margin of error, and I usually double test. I’ve double tested beta hydroxy once, but would obviously prefer not due to the cost of the strips.


    • MCT is, as you say, a catalyst for some. Most folks can only tolerate so much of it, typically between 15 and 45 mL per day. Yes, glucose variability is about 10% on those strips. Seems a bit better on ketones.

  • Andy

    I have a couple of questions. I have been utilizing LCHF for about 4 weeks now. My carb intake is about 20g a day. My protein is around 130g (lean body weight is 150). And my fats represent between 75-80% of my intake. I’m shredding weight like I never had before. And it’s been very easy, because I’m satiated all the time.

    However, as a triathlete, I’m struggling. My long easy runs are brutal. Prior to switching to this diet, I would hold my long easy runs at a 9 minute pace with a HR of 150. I could do this pace all day and usually run my 20 milers feeling good afterwards. Now I’m struggling to keep a 10 minute pace and my HR is about 153. And when I say struggle, I feel like I’m running on legs filled with lead. Additionally, my swims (I’m not a very good swimmer) have also been affected and after a 100m warm up, I can already feel my arms and legs burning.

    I read about your fueling over the course of your 6 hour ride. It occurred to me that I’m pretty depleted. Unfortunately I have no idea how to replenish my glucose deficiency without knocking my self out of ketosis. I have a 15k trail run tomorrow and have a feeling I’m going to be struggling with it. I thought about experimenting and increasing my carb intake tonight and in the morning, but with what? How do I eat enough carbs for it to be useful tomorrow? And when do I do it? And will that effect ketosis? Will my body quit using fat as fuel on the race if fuel up with too many carbs?

    Thanks for all you do and insight you could give,

    • No quick answer to this, but there are 5 or 6 posts throughout the blog that address this, including the one you’re commenting. Did you see how much CHO I ingested while remaining in ketosis, given my expenditure?

  • Billy Mitchell

    Hey Doc,

    For those of us who use the low-tech way to monitor ketosis (urine strips), what do you think about the idea that seeing red-purple on the strips after several weeks in ketosis isn’t really a good thing. I always thought it was,
    but then I read an article by Steve Fowkes where he talks about being in fat burning mode vs being ‘efficient’ in fat burning mode. He says that acetone breath and dark colored urine strips indicate not being efficient in fat burning mode and that excess ketones in the blood results in excessive cross linking. My strips are consistently dark red-purple when I test.

    • Billy I have zip-zero insight into strips. Sorry.

  • Naren


    I have greatly benefitted from all the information you have shared through your posts, videos, and podcast interviews. Love the content, love the delivery even more.

    Like a lot of others, I too find myself eagerly awaiting the next Eating Academy article. Especially the Insulin/Leptin one, which according to the Coming Soon page is 9 articles away.

    NK (confirmed through blood ketone measurement) took me (31 yr. old resistance-training male) from 25% body fat to 15%, after which the fat loss stalled. Signs pointed to what the internet said was a case of low(ered) leptin levels. The internet also said I needed a weekly “carb refeed”. I quickly dismissed that theory as bro-science until I found Mark Sisson’s articles where he too suggested refeeds as a tool for non-metabolically deranged, stalled individuals seeking to get to ab-territory (10% bf).

    From reading your other posts, I know that the short answer to whether carb-refeeds are necessary is that they aren’t, and that they pose more downside than upside by not allowing the body to fully adapt metabolically. The long answer… I suspect I’ll find in your Insulin/Leptin post.

    In 10 years of pursuing strength, fitness, and health, I have never been this excited. Thank you, Peter!

    • Ahh… the sad internet misunderstandings of leptin. Leptin levels are proportional to fat mass. Less fat mass = less leptin. Low leptin may well drive appetite, but there is no evidence that high leptin suppresses it in people without genetic defect (very rare). That’s the post!

    • Naren

      Thanks for clarifying the appetite part, Peter.

      How about metabolism and energy expenditure, do those go down as leptin levels drop? In which case if one were consuming not more but the same amount of food but now spending less energy, fat loss would then probably slow down or stall?

      These are the Mark’s Daily Apple posts which got me wondering,

      • Well, this is a much more complicated question with conflicting data. Certainly some of the finest experimentalists have shown, in some settings, that EE does go down at weight goes down. And while losing weight often implies reducing circulating leptin (see previous response), I don’t think anyone thinks the reduction in leptin is the cause of reduced EE. Other hormones, most likely thyroid, play a greater role if and when this occurs.

    • Naren

      If it is indeed thyroid playing a role in reducing energy expenditure as weight goes down, would you be of the opinion that increasing carb. intake would still not be the way to remedy the situation?

      Curious what your experience and the data you’ve seen suggest.

      Thanks again, very much!

      • They physiologic pathway to turn T4 into rT3 instead of T3 likely has more to do with caloric restriction than carb restriction.

    • Naren

      Fascinating. Thank you, Doctor!

  • Giselle

    Firstly – thank you for the work you’re doing and for making your findings accessible.

    I am a type 1 diabetic in the process of converting to the ketogenic diet. I’m watching salt etc and having no problems other than a sudden and consistent rise in blood pressure during the day. (Fine overnight.)

    Is this to be expected during the change over and will therefore subside?

    My blood sugars are already improving dramatically, (normal most of the time) but I have retinopathy so high BP is not good. GP blames the diet – but then he’s very anti it.

    I really don’t want to have to give up!


    • Giselle, you find value in reading the book by Dr. Richard Bernstein, who is himself a T1D. Might be worth sharing with your doctor, too.

  • Norm

    We really need a post from Peter on leptin! I have personally come to the understanding so far that in lot of cases it is calorie restrction that triggers thyroid like symptoms/issues and weight stalls but mostly it is carb restriction that takes the blame. In carb refeeds is it more calories or carbs that apparently kick start the metabolism? Similarly CarbNite solution recommends under 30 grams of carbs with one night of carb binging, here, is it going under 30 grams of carbs causing the fat loss or carb night.? I would argue it is low carb. John Kiefer as he describes in CarbNite Solution, was on ultra low carb diet for 5 weeks and then he binged on donuts one night. Couple of days after that he noticed fat loss, this according to him was the birth of CarbNite Solution. We have to ask here: is it the continuation of ultra low carb that caused fat loss or donuts? In the case of leptin and satiety issue we have to ask why does it not work in obese as they have plenty of food available, they still have to eat a lot and high leptin does not trigger/cause fat loss there. As explained by Gary Leptin is a down stream effect of insulin. We also have to ask how metabolically safe carb refeed is long term as this way one is really beating the insulin with the hammer.

    • Naren

      Thanks for sharing your thoughts, Norm.

      As much as I’d like to think I was eating adequate fat while being in Nutritional Ketosis, I think I might have succumbed a bit to the fear of fat. In addition, the inherent satiety of a keto diet probably put me into a calorie restricted state leading to low thyroid-like symptoms and slow/stalled fat loss.

      The hedonistic pleasures dangled by the refeed camp only make the bro-science distractions worse.

      Moral of the story: EAT MORE FAT.

  • Kevin

    I think the answer to this question is on your website but I just have not been able to find it yet. In the absence of insulin because all you ate for a meal is fat, what happens to the fat that you digest?

  • Giselle

    Thank you – yes I am very familiar with Bernstein – but no mention of BP.

    Might have cracked it though – could be the cut in caffeine. Reduced my tea intake because of restricting milk. A cup of black tea seems to bring it down. Odd but seems to work – thought I’d let you know in case others find something similar.

  • Kevin

    >> See fat flux post.

    Thanks Peter. I had already read that, and I am not sure if the answer to what I am after is in there or not. It could be in there somewhere but some of it is over my head.

    What I have gotten from all the LCHF discussions (simplified) is that fat does not make you fat, it requires insulin to store ingested carbs and fat as fat, but it requires carbs to raise insulin while fat will not raise insulin. So my takeaway from that is that if you don’t eat carbs, but just eat fat (again, simplified), your insulin will remain low and the fat you eat won’t be stored as fat and it won’t turn into triglycerides in your bloodstream. But if this is the case, what happens to the fat you just ate (whether you are in ketosis or not)?

    I am looking for a simple explanation of this because I get asked this all the time when I say I am on a LCHF diet. They all, of course, think that fat either turns directly into fat or clogs your arteries. I tell them that fat only gets stored as fat when you also eat carbs (or something glycemic) and that it is carbs that turn into triglycerides, but I am not sure what happens to the fat that we eat when we don’t eat carbs. Does it all come out in our stool?

    • Re-esterification (RE) as described in that post.

    • Yossi Mandel

      What Dr. Attia is pointing to is that you oversimplified in saying fat does not make you fat under any condition. It may not spike blood sugar and increase insulin, but it also doesn’t remove insulin entirely (which is dangerous). As long as some insulin is present in the body, fat storage is possible.

      While eating fat vs carbs, the basic difference is that you can eat an amount of fat of equal geometric area to an amount of carb (even though the calorie count is unequal) with vastly different results, meaning the calorie count is not relevant. So let’s say take 2 piles of food of equal size, one carb and one fat, the carb pile being 2500 calories and the fat pile being 4000 calories (varying per person), you will not (immediately) gain weight. But you will gain weight in either case if you eat more than that pile of either carb or fat.

      So you still have to count grams of fat, because if you eat more than that pile of fat, you will gain weight. If you overeat the fat, you will still have the advantage of controlled blood sugar, ketosis, insulin sensitivity, lower inflammation, appropriate leptin & ghrelin levels, etc., but you will gain weight as the body re-esterifies the fat it previously released from fat storage as it is not needed for energy and esterifies the new fat you’ve eaten.

      This is a simplification of what happens to most initially people under most conditions. Dr. Attia mentioned that he’s had to solve other health problems in certain patients to create fat loss, without mentioned what the problems where (elsewhere he mentioned thyroid problems), but that his first approach is always to cut down on fat consumption within a HFLC diet.

      Later on, the carb consumption will lead to much greater weight gain because of constant hunger driving up the total consumption of the carbs, sometimes to 8000 calories a day or more! Meaning that in an estimated 70% of humanity, you can’t continue eating 2500 calories of carbs a day indefinitely, because the hunger will lead you to increase calorie consumption, but you can continue eating the same 4000 calories of fat indefinitely with no desire to increase. That is the real advantage of fat over carb.

  • Wesley Hurrell

    Thanks so much for your invaluable contribution to health. I am a nutritional biochemist (have my own sports nutrition business) and enthusiastic competitive cyclist/triathlete who has been trying wholeheartedly a well formulated ketogenic diet, while undertaking training for an Ironman triathlon. Sadly though, 8 weeks in and my training is still suffering badly (greatly reduced power/energy) and have grown accustomed to a feeling of lactate onset at significantly lower exercise intensities. I regularly measure blood glucose, ketones, and lactate before/after exercise and have noticed trend for high lactate levels (6.0+) even when training below normal threshold pace/power. My ketone levels have only hovered around 0.5 – 0.8. I am supplementing with bullion, keeping a lid on protein and generally keeping carbs around 50-60g. The other key bit of info is that I am -and have always been extremely lean (7-8% BF) so insulin resistance likely not a problem (although father has type II diabetes + metabolic syndrome). To give you an idea, my FTP is normally around 285W, I can normally easily run sub-4 min ks on up to 20K runs and I weigh 57kg with a height of 176cm. But I haven’t been able to get close to those numbers since going keto. So my reasons for taking on diet are purely performance motivated, which is why I’m starting to get disillusioned with it all as I simply can’t perform as usual on training rides with mates. Just wondering if you might be able to provide some input, particularly in the context that I am very lean. Do I need to experiment up low-gi carb intake? What metabolic situation would explain a lactate value of 6.0, a ketone value of 0.8 and blood glucose of 5.3 after an 1.5hr easy-moderate session (run-swim-run) in morning after overnight fast and consuming only water, plus a couple of tablespoons of virgin coconut oil before exercise? Can’t work out why lactate so high and feel so lousy. BTW – I love all the other benefits…less hunger, better concentrate, better sleep etc.

    • Too complex a problem for me to solve without knowing more. It takes me a while to figure these things out with clients. Could be an adaptation issue, could be many other factors.

  • Kevin

    >> Re-esterification (RE) as described in that post.

    Doesn’t that just cover the part of the equation for how much dietary fat gets moved into the fat cell based on how much insulin is in your system? I don’t see where it says what happens to the dietary fat that does not go into the fat cell because insulin is not present in quantities to store it all. (Sorry if I am just being dense. But this is something that I have been trying to find the answer to for a long time. :-))

    • Yossi Mandel

      If there is any insulin present at all, fat will be stored. Only conditions like type 1 diabetes that suppress insulin entirely, meaning down to 0, lead to no possibility of fat storage.

  • Kate

    Simply stated: is it possible to get fatter while in NK? Can you store fat at the same time as you burn it?

  • Jonathan


    Thanks so much for the info. Your website is a fantastic resource.

    I’m having trouble finding much information that specifically addresses fueling for a 100 mile ultramarathon while in NK. I’ve been experimenting with ketosis and can comfortably do 25-mile very hilly training runs on nothing but water but I’m concerned about fueling for my upcoming hundreds this summer. Assuming one starts a hundred firmly in NK, will taking in 1-2 gels a hour during a hundred definitely kick you out on ketosis? If so, would the consequences be devastating for performance? I know that Mike Morton, for example, started Western States last year in ketosis but took in plenty of gels during the race. His experience seems to suggest that UCAN + MCT oil as fuel for very long efforts isn’t the only way to go.

    There are a lot of factors here, I know, but it would be great to hear what you think on this. Thanks!

    • Why do the principles here not apply to Western States or other ultra-marathons?

  • Jonathan

    Thanks for your reply!

    I’m trying to figure out the most efficient way to carry and consume nutrition during a long ultramarathon while being in NK. This post is very useful in thinking about glycogen deficit and it got me wondering about why not simply consume gels during hundreds (albeit in a much lower quantity than someone who isn’t in NK). I love cashews but they’re not nearly as easy to carry over long distances as gels. I realize that insulin response varies from person to person, but I’m wondering if, applying your principles of glycogen deficit, gels would work just as well. And if they did kick you out of ketosis in the middle of a hundred, would there be catastrophic consequences? I know the way to find out is to try but I’m hoping you might be able to save me from some unpleasant trial and error. Thanks again!

  • Dan Walker

    Just my perspective here, but it kind of seems to me that sometimes the idea of really needing to do your own individual testing, one variable at a time, gets drowned out. As you mentioned, there really can be such a wide variation in response that is specific to each persons experience, what their goal is, and all the factors controlling their physiology that making generalizations rarely work accurately, and definitively, in every specific case. It definitely takes time and patience but the nice thing is a lot of the basic testing you need to do, and the monitors you need, are now pretty easy to get and relatively inexpensive, portable, etc. I think it can be said as well that really going through the process, doing the groundwork, and getting everything dialed in so specifically for your own situation can be a rewarding process in and of itself and really reinforces what you have learned. Also, if you have some extra resources to throw at the whole issue there really are some neat things you can test and do that only super elite athletes would have had access to before and Peter has outlined many of them here on this website. Especially if you live near a large university that has an exercise physiology department that offers services to the public. Just a suggestion here too about NK and fuel for something like ultra races you describe that you may want to consider is the old native tradition of making Pemmican which is a portable, stable source of energy. You can buy it already made or get plenty of recipes online to make your own custom blends. Even adding berries to it and all kinds of other interesting ingredients.

  • Ron

    Dr. Attia,

    CarbNite was previously mentioned (Norm) and I would like to know what you think of the “protocol”? There are some fitness advocates that endorse it as well.

    And conversely, (the statement that caught me by surprise) Kiefer claims that if you raise/spike insulin high enough (the overall concept of the protocol – glycogen being depleted), you actually burn fat instead of store it.

    • Ron

      I’ll take that as a resounding NO! (high insulin burns fat)

  • Tony

    Thank you for taking the time to write this amazing article, and just finished watching your presentation “An Advantaged Metabolic State: Human Performance, Resillience & Health” great stuff. I have to admit i geek out as well when it comes to ketosis and improving metabolic performance. I’m just someone trying get into optimum shape.

    someone else asked, “What are your thoughts regarding a ‘time window’ for optimum carb consumption following a “glycogen deficit” generating period of activity?” — and still be able to remain in a ketogenic state.

    you replied, “If you have a glycogen debt, you’re going to prioritize filling it regardless of timing, more or less. The “window” is a largely artificial construct, at least for most folks. It may be more significant for an IR person, where post-exercise IS in increased slightly.”

    what im wondering is… after the glycogen stores are depleted, will your liver work to create more glycogen to replenish the debt? and if so, how much time would I have to consume carbohydrates to replenish the debt myself before it would beat me to the punch?

    sorry if it’s a silly question, im just trying to understand it better. thank you, amazing work.

    • Glycogen is replaced primarily from ingested CHO. Some glycogen get replaced from glycerol, a byproduct of TG breakdown into FFA.

    • Max

      Main question:
      Consecutive anaerobic work –> gradual glycogen depletion –> Best behavior to be able to maintain anaerobic work (for example next days)???

      What about highly anaerobic workouts on consecutive days?
      If Glycogen is replaced as (Mr. Attia) explained, it seems to be even
      “necessary” to ingest more CHO than consumed on usual days in ketosis,
      in order to be able to do comparable anaerobic workouts on consecutive days.
      Is there a (natural) way (i actually don´t see) how the body can replenish glycogen after
      anaerobic workouts besides “consuming” some more than usual?
      If not, it seems that after anaerobic workouts the used portion of glycogen has evitably
      to be replenished through nutrition to be able to do comparable workouts again.

      What´s your opinion to that?

  • Sharon

    Thank you so much for the time you spend on this great website.

    I’ve tried losing weight before via ketosis, after the first 20 lbs (water weight) I just didn’t loose any more. I don’t know if I wasn’t eating enough fat or if I was eating too much protein and fat? I was hardly eating any carbs, at least the ones I knew about. That’s why I wanted your thoughts on the following question and answer posted on the “Ask the Dietitian’s website, category “Fad Diets”. How does one know how much glucose is being provided from the protein and fat they eat? Do I need to invest in some sort of gadget to know if I’m in ketosis? I used ketone strips before but hear they might not be accurate. I’m so desperate to get my weight under control.

    Copied from “Ask the Dietitian’s website, category “Fad Diets”

    Q. Can you explain ketosis to me?

    A. In diets that contain fewer than 900 calories, all food eaten including protein and fat is broken down into glucose to provide fuel for the body. Protein and fat are very expensive fuels for your body. You can only convert 70 percent of the protein and 30 percent of the fat you eat to glucose. The nitrogen from the protein is excreted in the urine. This leaves no protein for repair or maintenance of muscles and organs. Also, in diets containing fewer than 130 grams of carbohydrates, ketosis occurs and your body starts breaking down muscle and lean tissue to provide glucose for brain and nerve fuel. Your body’s first need is for fuel. Your body’s use of dietary fuels cannot be changed drastically by altering your diet.

    Your body can and does take stored fat (as triglycerides) and incompletely breaks it down into ketones, which can be used as a fuel source for muscles and organs. To completely breakdown body fat, you need glucose and oxygen. If glucose is not available for fuel by your limiting dietary carbohydrates, your body learns to run on ketones, but your brain doesn’t. Your brain gets sluggish because it only runs on glucose. Your body starts breaking down muscle and organ tissue to provide the needed glucose for brain tissue. Protein contains glucose in its structure and it can be scavenged for use by the brain and nerves. Quick weight loss diets claim they spare muscle protein, but they don’t. A diet high in protein and low in carbohydrates does not spare muscle protein from being broken down, unless you eat enough carbohydrate. As you continue on a high protein, low carbohydrate diet, the amount of ketones increases and ketosis occurs. Ketones are very irritating to your kidneys and the kidneys try to get rid of the ketones through the urine.

    • The “fad diets” website needs to get some facts straight. I’d recommend a new reading source. Consider Phinney & Volek’s “Art & Science of LC Living” as a good starting point.

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  • Louise South Africa

    Wow, THANK YOU for your blog and for being SO informative and going into detail. I am a female athlete (weight training – not pro, but for fun) living in South Africa and somehow, luckily, I found your blog. I am experimenting myself with very low carbs and high fat and also now going in NK. It’s all so fascinating. I am just LOVING reading everything you write. Keep posting. You are doing us all a wonderful service.

    I also noticed that after a heavy leg training session my weight almost always goes up. Females need to be very wary of the scale – rather we should eat and train to feel healthy.

    Thank you SO much. I really just wanted to say I appreciate your blog and I am reading as much of it as I can.

  • mkn

    Hi Peter,

    I found this link suggesting risk of reduced digestive tract mucus from a LCHF/Keto diet.
    Wanted your comments:


  • Dare

    Peter, any tips how one could calculate or at least try to “guess” how much glycogen is used during a weight training routine and/or high intensity intervals like tabata? In both cases body suppose to be burning energy long after the exercises, at least thats what Ive been told?

    • Can be measured, but it’s tough. Need to know VO2 and VCO2 to have an fidelity.

  • Ray

    All your experiences make me lol cause it sounds so much like me, but I’ve never tested I calculate correctly and I might do 50 gr carb most days but work out hard as well. My wife is now doing this with me. Any advice for female. She’s raced for about 4 years

  • Ohad

    Hi Peter,
    This post is very interesting and opens up a whole new array of experiments a keto dieter can perform on himself/herself.
    I read in some places that bodybuilders who go into ketosis and out again every week sometimes use Alpha Lipoic Acid as a means of suppressing insulin spikes in order to go into ketosis faster (maybe also shortening adaptation time) and to better stay in ketosis.
    Is it possible ALA can be used with food (like an alka-seltzer) to “cheat” ketosis the same way you use long bicycle rides?

    • I’ve not found this to be particularly meaningful.

  • Tish

    HI Peter,
    I have a couple questions for you. I began ketosis for health purposes, supervised by physicians. I’ve always been small to begin with, so my health was my primary goal of ketosis, not weight loss. However, I actually have gained 10lbs of fat after being “keto-adapted.” I’ve always been very active and still remain active, resistance train 5-6days/wk. Do you have any thoughts on this? Although I feel great in many other aspects, I also have negative feelings as well such as I feel like my heart beats are more prominant and faster, I can’t seem to get my best strength back, I went from being cold all of the time to being hot all of the time. Is it possible that maybe I just have a different body type and maybe a different diet is better suited for me? I didn’t go crazy and eat all of the bacon and sausage I wanted. I’ve been eating eggs, coconut oil, grass fed beef, bone broth, organic chicken, olive oil, fish, grass fed tallow, very little veggies in the form of spinach and cauliflower mainly.
    My other question is, I believe in eating the way our ancestors did, in regards to whole, unprocessed foods, because I feel like we’ll never truly know the real answer in regards to what they ate. I believe ketosis was valid in regards to going days without food and depending on the area, seasons w/o veg/fruits. But I don’t really find it natural to go out of our way to consume tablespoons of coconut oil either. Do you see a problem with a diet combined of all of the healthy food groups? When I say this, I mean taking away grains and dairy (since they seem to be most problematic) and eating a variety of veggies, fruits, nuts, animal, fish, healthy fats. Does it have to be high carb or high fat? I tend to see a pattern with people who go on diets. That their inital diet was combined with many processed foods and that’s why they saw so many benefits while dieting. Because they took out the processed foods, not necessarily because of the specific diet choice. I guess my main question here is the subject on fruit. There’s much information out there that suggests it has the same effects on the body as does other unnatural sugars. I’ve spoken to a lot of people who do very well on a healthy high carb diet of which consists of lots of fruits, and some combined with many veggies, nuts, seeds, little fish/animal, but no processed foods. Do you believe this is setting up for future failure and problems? Maybe initially for those with insulin problems? Or maybe not so much after their body is healed from those? There are studies that show the harmful effects on fruit but then rebuttles that they were based on processed sugars and no actual evidence based on natural, whole fruit.

  • Ewa

    Hi, Finally I found a good source of information for athletes practising LC diet.
    I have been on a low-carb diet for 2 months. In a few days I ill have my first mountain race (ca. 30 km, altitude increase +1320m, approx. time 3,5 h of effort). In my trainings runs for this event I recorded a very high heart rate (up to 180). Now I have a question about nutrition. In the book “Art and Science of Law Carbohydrate Performance” by J. Volek and S.Phinney, they say thay in trained athletes fat oxidation can be maintained above the level of 65% VO2max. However what will happen when I hit and maintain a much higher level of heart rate for a longer time ? Should I eat any carbs (potatoes, nuts and the like) before/during that race in order not to bonk or stay with fat only?

  • George Coffey

    I discovered this site a few days ago and have been reading everything on it every chance I get. Great stuff. Since you use a power meter I’m wondering if you use the Training Peaks software or are familiar with it? If so, do you think the kcal reading it computes for a ride is accurate and could be used along with my RC to compute my glucose requirements after a ride?

    • Yes, I use TP. If you use a power meter, kJ is approximately equal to kcal (but fluke of conversion), but say nothing of RQ, which you need to test separately.

  • Paul Arena

    For any endurance athlete, I find this to be the best blog post ever. Especially for anyone that wants to utilize fat as fuel during exercise.
    Having said that, I just finished the Seattle to Portland Bike ride (203 miles in 16 hours) in 91 degree heat in one day. Brutal. Just Brutal.
    The day before the ride I was at a fasting level of 0.8 mmol ketone level. Good but great.
    I went in the the ride knowing at some point I would need carbohydrates but not sure when. So I bought and took with me foods that were fat containing and foods that were carbohydrates, like energy bars and shot-blocks.
    I had bacon and eggs for breakfast then started the ride. I felt great for about 75 miles then I lost power output and I had the intrusive thoughts of devouring anything sugary. I had to cave in and chow down a shot-block package.
    The rest of the ride was simply impossible without carbs. Which, after reading this post, is reassuring considering I can still be in ketosis after eating so many carbs. CONTEXT MATTERS. Not Sure what my RQ is…but it was obviously higher than .75.
    Peter, my question: How do I test my RQ? Do I need a university lab?
    Paul Arena

    • Anyone who can test VO2 and VCO2 can measure RQ. Check folks who do metabolic testing.

  • Paul Arena

    I was wondering if you have heard of this “MuscleSound” product ( It’s designed to measure intramuscular glycogen content. It’s none-invasive technique is much more preferred for field use then muscle biopsy for obvious reasons. If you’ve already seen it then sorry. Just discovered the founder (Dr. San Millán) through a Twitter post by Tim Noakes. Makes a great case for keeping glycogen stores in an optimal range for high intensity athletes. Seem like it really is important to get Carbs in the system right after the glycogen depleting event. The question: how much is just right? Probably different for everybody.

  • Marco

    Regarding oxygen which is VITAL to health, what is your take on this statement Peter? Daniel Hamner, MD, states:
    “A diet high in complex carbohydrates — such as fruits, vegetables, whole grains and legumes — significantly improves the blood’s ability to transport oxygen to cells. A high-fat diet does the opposite — it reduces the blood’s oxygen-carrying capacity”.

    I follow your regime but am worried about oxygen for mental clarity, for not developing cancer cells, for proper metabolism, for skin and blood flow etc…

    • First of all, I don’t have a “regime,” nor do I have “regimen” if that’s what you mean. I have no idea why you’re asking me for clarification since I’m not the one making this baseless statement. Ask Daniel Hamner, MD for some evidence in humans that a low carb, high fat diet reduces oxygen carrying capacity.
      You’ve got to learn to think for your self, Marco. If I wrote that high carb diets made you grow a tail and horns, would you email some high carb guy asking if it were true?

  • Norm

    Hi Peter,
    On a low carb/keto diet, does low insulin have anything to do with raised LDL-C/LDL-P?

    Also, how many grams of protein in one meal would be too much to stay in ketosis?


  • Marco

    I can only connect dots to a degree, while you in the field of extensive research, can accurately debunk or grant the statement i cited. That MD does not now about YOUR science and dots you connected in medicine. Everyone is so specialized on a microperspektive that every field of study yields different results. I just wanted to know YOUR results about oxygen-carrying capacity on a “eat fat to satiety” recomendation you make. The above MD states it is reduced on a high fat diet but you with experience in cancer research might know a whole lot more about oxygen (oxygen deprived cells develope cancer to a higher degree, right?) . So if you care to answer i would be grateful because i cannot comprehend studying complex bonds on my own as a 22y student, just accepted to theology and passing on studying molecular science.

    • Marco

      I am glad you responded the way you did and i actually would think for myself and studying harder if i could but i am exahusted after the last year, studying endokrinology, brain, EMF, necrotic burned celltissue from eating cooked animals and also glycation end-products, pinal gland, sleep, sprouts, raising magnesium levels in brain and body, and everything a functional medicine doctor would do, in order to gain optimal health. I cannot falsify that MD’s statement about oxygen cause i dont have the mental stamina like you, to cope with so so much descriptive information like biology. I am so thankful for your blog though and your efforts to the people!

  • janet

    thank you for this website. I am new to keto diets and have been studying very hard and applying the principles. for an overweight person, I have never felt better getting off sugar and wheat and consuming fats and keeping carbs under 30 total, with moderate protein. I have been searching your site for fiber information. can you recommend a source for my studies of how fiber affects ketosis? my main question is why can’t I subtract fiber to reduce the carbs and use the net? what happens in my body with fiber and how does this affect insulin or ketosis? thanks so much. I couldn’t find this in low carb living, or jimmy moore, or fiber menace or maria emmerich. do you have any thought on why I can’t subtract fiber from total carbs to reduce total carbs?

  • Marco

    I followed your lesson about thinking for myself and i concluded vaguely this:

    Theory of oxygen carry-ing possibillities on NK and LCHF: More growth factors from fat, good fats that improve oxygen absorption and healthier gut flora that also does this, lower systematic inflammation by lowering sugar content > insulin >, less stress in the digestive system (as temporarily insulin resistance by high GI carbs or abundance of mid-GI during a food-window, will decrease absorption to T3 and many other hormones i speculate)

    Conclusion: Fat does not hinder oxygen-carrying possibillities. The MD i cited were right in the sence that insulin can by growth factors carry oxygen, but a NK or LCHF method can by above described plus with excercise > natural HGH > Sleep and Colostrum, also carry oxygen, without all side effects of sugar. Are you happy with efforts even though i mostly speculate? 😀

    • Not sure of your conclusion, but great to see the process.

  • Dillon Perron

    Hi Peter,

    I am a national level swimmer in Canada and my 17th year of competitive swimming starts next week (after a month off) and this will be the first year I can honestly say that I will be taking my nutrition and diet very seriously, previously I have had the classic athlete attitude of, “I train so much I can eat what I want,” and I have you to thank for my change of heart! By the way I give credit to anybody who does open water swimming…. I don’t know how you guys do that, don’t you want to see the bottom!

    This is a fairly general question and I understand if it is unanswerable. Since I had a student-athlete on a tight budget, I can’t afford to buy ketone blood strips, superstarch, or have the ability to measure my VO2 max accurately. Essentially meaning I am forced to do a lot of educated guessing, which maybe isn’t a bad thing. Since I train 3 hours every morning (1 hour weights and core, etc and 2 hour swim) and head to class right afterwards want to implement some kind of post-workout drink that would refuel my depleted glycogen stores, I am a sprinter to mid distance athlete (50, 100 fly and 50, 100, 200 breast) and depending on the day I could be doing anywhere from 20 mins to 45 mins of anaerobic work.

    Long story short my question boils down to: Since there will be no way for me to know how much glycogen I have burned in practice, I figured I would take anywhere between 40g to 80g of carbs (waxy maize) after practice depending on the type of work I put in that day. Since the initial carbs are dedicated to replenishing glycogen stores, excess carb intake would give me a spike in insulin and not enough carbs would give me a spike in ketones. Being a sprinter, do you think it would be more appropriate for me to air on the side of excess carbs after practice considering the amount I train and since I am sprinter I’m sure I want to make sure my glycogen stores are not in a state of depletion? During my month off (literally zero exercise basically) I have hovered around 50g of carbs (mostly from fibre) a day, I assume once I start training again my carb in take could nearly double but if I understand all my research correctly this would still be a beneficial step forward in terms of my nutrition. Maybe I’ll fall out of ketosis but I should still be more metabolically flexible than I have been in the past… I think?

    Thanks again for all your help!

    Dillon Perron

    • Dillon, don’t assume NK is necessarily the optimal state to maximize performance for someone doing 30 to 150 second events.

    • Thanks for your response, and you are probably right. I bet being in NK could have some major disadvantages for a sprint race. Although I believe being more fat adaptive/metabolically flexible (not necessarily in NK) could be beneficial for my long training sessions… which in turn should allow me to train harder. and my racing could improve. I shall learn shortly as the season starts up again!


  • Paul

    I’m desperately trying to use NK to resolve some metabolic issues (induced by candy diet and anxiety/stress in teen years) and chronic severe insomnia. When I went low carb, I lost the ability to sleep at all (I’m guessing this is because of serotonin’s relationship to carb consumption and shuttling tryptophan).

    I just started doing 50% calories from MCT oil to allow for higher carbs, but I’m not sure the 400 or so kcal from carbs per day is enough. Do you think strenuous exercise every single day and appropriate carb feedings would help someone in my situation?

    The info on ketogenic diets isn’t plentiful and I am grateful to have just found this blog, I do wish there was more information on the MCT version of the diet.

  • Phil Morris

    You state’the first metabolic priority for ingested carbohydrate is glycogen replenishment’. Does this also apply to glucose generated by hepatic gluconegenisis?

    • If the glucose being made by GNG is not immediately being used, then yes, glycogen formation should still be top priority (i.e., same as ingested).

  • George


    Maybe you or a reader can help. I’m 63, with no metabolic syndrome markers and under 10% BF. I think being near or in ketosis is a healthy way to live and after a gradual effort lasting around 3 mo. I finally went into ketosis a few days ago. The next day I went on a somewhat hard 45 mile (5500′ climbing, NP of 215w.) ride. I’m going to give Superstarch a try, but my order hasn’t arrived. On this 3 hour ride I nibbled over the course of the middle 90 minutes a fruit/nut bar with 20 gms of carbs and sipped some sports drink with 18 gms of carbs. I felt great at the end but just couldn’t eat enough the rest of the day without overdoing the carbs (I was already at 100 gms) and wound up 900 kcal short of what I should have eaten. The next day I went on what should have been an easy 55 mi./3 hour spin (1500′, NP 190). I did it with an all protein breakfast and just water. I was pretty tired at 2 hours and the final 10 minutes were a real struggle. I ride 150+ miles a week and these two back to back rides were nothing unusual. I realize my carb fueling was off. Here’s my question: Is there is anything in the way I fueled (of didn’t) for this second ride that would have caused extreme muscle soreness in my thighs? I suffer from DOMS no matter what I do, but usually not for 48 hours. This soreness was not noticeable while riding, but started the minute I got off the bike, has not gone away in 24 hours and is extreme, even for me. Are there any reports of excessive muscle soreness during early ketosis that you are aware of? I hope you have time to comment. Thanks for all you do.

  • Monica Smith

    “Not sure of your conclusion, but great to see the process.”

    LOL! Not only does your blog provide a wealth of useful information but also a wealth of entertainment.
    Please don’t ever stop this blog. I absolutely LOVE it. You are a saint 🙂


  • janet

    I was wondering if you check your blood ketone levels and the time frames to do this.
    would I do this in the morning, after intermittent fasting, after eating, before eating, when do I do this?
    what are the best times to do this?

  • John Theobald

    I enjoyed reading your article Ketones and Carbohydrate can they co-exist. Regarding maintaining ketosis. I have a keto ratio calculator on my site at . If the ratio (based on the Woodyatt formula) is above 2 you can be sure you’re in ketosis. If you over eat carbs you can still maintain the ratio by increasing fat until you reach the desired ratio. This may mean depending on how many carbs you ate that you have a day with a large number of calories, but you won’t lose keto adaptation. The ratio is all important in maintaing ketosis. Try is I’ll be curious what you find.

  • Mirek

    I just recently discover your blog, and I would like to thank you for all hard work and great posts. I’ve been on NK for two weeks and I’m training everyday at lunch time at work. Before NK I was able to do sprints on around 85%MHR, but while on NK I’m not able to sustain 85% of MHR for long. My question is for ANAREOBIC training when I should eat carbs ? Do you have some basic rules how to use carbs with ANAREOBIC training and when to eat them, before or after training ?


  • Sumit Bhatnagar

    Hi Peter,
    I read in your post that one day you had Indian dinner on your daughter’s B’day and It took you 2 days to go back into ketosis (>1 mmol). I got a bit surprised that you could get back in such short period. I mean, it took me around two weeks to reach > 1 mmol level when I started my own experiment with Ketosis. How were you able to do that?
    Is it because your body was already in the keto adapted state and so it still had preference to burn more fat than carbs ? Also, During fully keto-adapted state, if someone does carb loading, does your body just shifts to burning glycogen totally and you go back to square one ?

    • Probably because I had already been in ketosis for so long.

  • Anna

    I have watched some for your youtube videos and read several articles on your site. I have had past success on a very low carb, high protein diet ({Protein Power by Drs. Eades). But I was afraid to eat fat and thus had to consume tons of protein to eat enough. It worked for years, but then I started adding carbs back, had several kids, and gained a ton of weight. I am just learning about Paleo diets, and so have been doing Protein Power (loosely) and with Paleo foods. Eating 1200 calories a day, 20% fat, 10% carbs, and 70% protein. I’ve lost @ 4 lbs a week. Now that I am reading that Ketosis cannot happen without much lower carbs and much higher fats, I am adding coconut oil, avocado, almond butter, etc. But I am still confused about 2 things, I am hoping you can help with. SOME say protein can be as high as 120-150 g a day, carbs 30 grams, and the rest fat. But if I understand your examples here, I should be eating much less protein and more fat. I am a 40 yo female restricting calories to 1200 net daily, after adding back calories burned 3 days a week weight training. I am really afraid to eat too little protein and too much fat. (1) What are the recommended actual macro %s for someone on a calorie restricted diet to allow for getting into and staying into Ketosis, as there seems to be a wide range of opinions on this? (2) If I raise caloric intake, how much do those macros change? I need to lose 60 lbs. (3) Does it matter if the %s are kept in balance for each and every meal, or is it ok to eat mostly protein in the morning, with lunch having just salad and an avocado (low protein) for example? (4) What is the max amt. of protein I can eat (or %) and stay in Ketosis? Thank you in advance for answering my questions and for your great website!

    • Anna

      I have since found a min. protein calculator, keto calculator, and ketostix. So I now understand some of my questions. I still would like to know 2 things if you get a chance to respond (I know your are very busy). (1) Do I need to maintain the keto ratios at each meal, or is each day sufficient? I would presume each meal for optimal insulin regulation. (2) My ketostix stay Mauve, about 4 Mmol, so I believe I am in ketosis. When I use a keto-calculator (on flexibleketogenic website) it gives me a range of 1-1.5 mild ketosis, 1.5-1.9 moderate ketosis, and 2.0+ optimal ketosis. I have been in the mid-range consistently. It there a need to be in the 2+ range or to get to eggplant purple on the ketostix (8 Mmol) in order to be in ideal nutritional ketosis, or is moderate level still fine I am losing weight? I cannot find this info. anywhere and want all the benefits of ketosis. What is your recommendation for target range?

  • Sam

    Hi Peter,

    I was wondering if what they call “low carb limbo” was a fact or myth. Is it true that you must either be producing ketones for the brain or consuming at least 150g a day of glucose, otherwise your brain won’t have sufficient energy and you will essentially hit a wall?


  • Anna Sutton


    Fantastic site and great posts!

    I have just been “experimenting” with ketosis for about 3 weeks, mainly due to a big jump in blood sugar levels (stable 4.2 in 2011 to steady 5.7 -5.9 in 2012-4) . My exercise levels are not what they were (about 1-1.5hr (post kids) ) vs 3-4hrs pre 2008 ( pre kids, when racing) but these are still well within healthy activity levels. I weigh 62kg more or less and hold about 49kg in lean mass (DEXA)- another “fat” but fit! . At my leanest (virtually starving myself), i weighted in at 53kg but actually my fat mass was relatively high for an athlete at around 15%. My target is about 56-57kg , around 15-17% body fat with blood sugars back to pre kids levels! (3.8- 4mmol)

    I have been “experimenting ” for a bout 3 weeks on net carbs 0.5mmol) and secondly, the slightest deviation sends me right back to home base. and it takes days to get back even to 0.4mol. I also notice the type of exercise certainly impacts post exercise ketone levels- very similar to one of your previous blogs)

    The other thing becoming apparent is that even with low total carbs < 30gram , as soon as my protein intake exceeds about 60g , ketosis stops! I wonder if some people are also more sensitive to dietary protein requirements than others and how this influences the availability of fat for fuel.

    I recently listened to a talk on how,, when left alone, various species choose their dietary protein preferences- Chimps were around 14% of total energy intake, dogs were about 14%, cats were about 50% and humans were about 12%. The important thing was the % of protein remained surprisingly constant across the period of the study (about 1 month from memory), (although different life stages had different % protein preferences) suggesting that it was the % protein in the diet , not the protein content (grams) that was important to the animal.

    However, It's actually quite hard to stay around this level (12% protein) on a normal western diet, particularly when in calorie deficit i wonder that in certain subgroups of people with fat mobilization disregulation , this protein set point also plays an important part in the obesity puzzle- ie their protein "tolerance" is on the low end and the excess protein consumed is essentially being converted to glucose and resulting in elevated insulin levels which ultimately inhibit that individuals ability to utilize stored fat- maybe this is why resistance training can sometimes be useful in reducing fat mass , particularly when on a low carb diet, it simply increases the protein requirement and shifts your set point so that your protein utilization is greater -hence reducing the amount of protein available to be broken down into sugars.

    I also wonder whether the same phenomena of insulin resistance and obesity that we see in humans is prevalent in companion animals- diabetes is one of the fastest growing pet ailment- possibly fuelled by v high carbohydrate and high protein , relative to their % requirements, despite energy content of the food often being in line with requirements,

    Again, just observations and my two cents worth and no research backing! I might try to play around with protein % rather than grams to see if this helps me on my quest.

    Keep up the great work!

  • VV

    Thanks for a great set of articles.

    A couple of questions:

    1. Can ketosis and glucolysis co-exist or they are mutually exclusive? I. e. if ketosis has started, does that mean that energy consumption through carbohydrates has stopped, or these two processes can go in parallel?

    2. Does ketosis start only when glycogen stores in the liver are fully depleted? If the priority for the digested carbohydrates is to first top up the glycogen stores and then to be used for direct energy supply, does that mean that in ketosis there is ALWAYS some amount of carbohydrates that can be eaten without taking the person out of ketosis?

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  • van phillips

    Hello Peter, I watched an excerpt from Dr. Michael Greger M.D.,, who went on to state that the cause of diabetes is saturated fat… He’s promoting a whole plant based diet. Are you familiar with his ’cause’ as he states? And if so, I would love to hear any comments you have on his statements of what he calls ‘science’.

    thanking you now, Van

  • Michael

    Hello. I’ve been planning on doing my strength powerlifting program and HIT training in the near future.
    I believe this follows your NK regime, but my plan is ketones meals with the exception of five TBSP of TwinLabs MCT Fuel (roughly 30g glucose and 22.5g MCT Oil) pre workout . Then followed by 50+ or – g of carbs from sweet potatoes. Then keto meals afterwards all at caloric surplus.
    Is that something you recommend and is that similar to your NK example?
    I just hope my body fat doesn’t increase so much. I may have to lower the carb intake to prevent that after I conduct this trial.

  • Lilu

    Do you have any blog or article on starting the keto adaptation….I am struggling with side effects. Thank you

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  • Jason Keck

    Hi Peter and all readers,

    Quick question: Do you know the ATP yield of of BHB per mol of respired 02?

    I have read that it is higher than the 120 kcal/mol 02 of glucose, but I cannot find the actual number anywhere……

    Thanks a lot if you have the time.

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  • barbara thatcher

    I am an avid crossfitter and believer in ketosis. Last year, at the age of 45, I made the team to go to the northern california regionals with five other twenty something year olds. I weighed 138 pounds and had 17 % body fat at that time. I was encouraged to eat more carbs to be able to manage the increased workload in preparation for the big competition. I did. Over the course of about 8 months, I gained 6% body fat, 20 pounds and only 2 pounds of muscle mass. My diet was primarily Paleo with some starchy veggies, otherwise pretty “clean”. I have been trying to get back into ketosis now for about a month. My carbs are as low as 10-20g a day, and my macro’s are 80% fat, 15% protein, 5% carbs, give or take. Testing my unine, blood and breath and I am generally in small to moderate ketones with these numbers. Highest I’ve been is 2.2mmol blood. I have lost no weight. Actually, I have gained about 2 pounds, depending on what time of the day I weigh myself. My abdomen actually feels bloated most of the time. This is an unusual response for me as I usually drop unnessecary weight easily while in keto. I’m taking all the appropriate and relevant micro-nutrients. Would love any feedback. I train high intensity work outs about 5 times a week for about 2 hours. I have been eating aobut 1600 cals in an attempt to create a calorie deficit. Quite confused.

    • Laurena

      Hi Barbara,

      I just read your post and wanted to share with you my experience as it seems pretty similar. The abdominal bloating that you describe would be something to look into. I had initial success of losing body fat and gaining lean tissue while in nutritional ketosis until I started experiencing abdominal bloating. Like you I started cutting calories but my weight kept fluctuating and I actually gained body fat. I discovered that I was highly intolerant to the whey protein that I was ingesting post workout through food sensitivity testing. I was also sensitive to a few other foods which was eating on a regular basis like sweet potato. After cutting them out I also made sure I had the proper nutrients for digestion and gut barrier repair. You might be interested in this study:
      It gives an insight on high fat intake, inflammation, metabolism and gut health.

    • Mark

      “Would love any feedback. I train high intensity work outs about 5 times a week for about 2 hours. I have been eating aobut 1600 cals in an attempt to create a calorie deficit. Quite confused.” <– This may be the issue. You could try increasing your overall calories to match your output. Forget about dieting for a month and see if eating more makes a difference. You can then reduce your food slower to create a deficit.

  • Diane Allen

    Dr. Attia and guests,
    I can see where all of you are concerned at a cellular level and the chemistries that evolve from the interplay of what you are doing to your body with ketosis, but if you view the body from a distance, consider only what effects the endocrine system and the actions roles each of the glands play in the body, you may better understand how many actual factors there are that interplay with the use of energy in the body. Organs that regulate blood glucose are the ones that pain me daily as well as the migraines that I have reduced in intensity.
    You are in the eye of the storm.. view from a distance and add time and energy used for immune response as factors….progression of disease. Both glucose and calcium play roles in immune response…..and inducing ketosis ages the organs and glands… but I will keep an open mind with your ideas.
    The natural nutritionist has an understanding that goes beyond the intensity of ketosis yet medicical interpretations can bring it all together.
    You can provide hope to many with your work !! Blessings to all of you.

  • Chris

    Love your books! On a quest to figure me out. Buy your premise.
    Initial Facts – 6’1″ – 255lb male. Beginning Insulin – 10. Initial fasting blood glucose – 105 fasting (yikes!) .2 Keytones (Xtra Precision).

    Strict eating for 3 months. <30 grams of carbs, <120 grams of protein, 75-85% calories from fat. Total Calories from about 1500 – 2300 daily. 2nd month started HIIT 3x week. 3rd Month started intermittent fasting – eat from noon til 8 pm only.

    2 total days of ketosis out of the 90 and then ony @ 1.2 mm (3-5 days a week tested – if glucose is low always test for ketosis) – Fasting Blood Glucose trending towards 95 – tested daily. Weight 252. Insulin at the end of 90 days was – 32! Yup, no typo. I am more than confused by these outcomes.

    23 and me – says that I have one mutation in the ACADM gene linked to MCAD deficiency. A person with one of these mutations typically does not have MCAD deficiency. I am wondering if this gene mutation is changing my results?

    The ACADM gene produces the medium-chain acyl-CoA dehydrogenase (MCAD) enzyme. MCAD is involved in breaking down fat from food and stored body fat into energy, which is especially important during fasting (going long periods without eating).

    Any insight!? Thanks in advance.

  • Michael

    What is the best/easiest way to track if I’m in ketosis at home?

  • Malvika

    Hi Peter,
    Thanks for your articles and videos. I myself try to follow a low-carb, high-protein and fat diet. However, being a vegetarian (I don’t take eggs also), I end up eating lots of beans and legumes, which have protein but have carbs also. How do you suggest I devise my diet?

  • Zach Harmon

    Dr. Peter Attia,

    Thanks for the wonderful blog, its been a gold gem for information. I’m a physical therapy student attempting the ketogenic diet and have been measuring ketones/glucose with the abbot machine you said you use. I have been doing it 3 weeks now and I have been going in and out of ketosis (using your more strict measure of at least 1mM.) still tweaking my protein to the amount i need I think and I’m still adapting.

    I have some questions regarding the long term use of the ketogenic diet. I enjoy being in ketosis because of the increased energy levels I experience and the prolonged periods of time I can go without refueling. However, after reading more and more literature on this, I have come across a concern that being in ketosis long term may result in increased peripheral insulin resistance due to the body wanting to spare the small amount of glucose in the blood for the brain instead of the muscles/liver. With that being said, would it be best to cycle through a ketogenic diet to counteract this potential issue? Is there any solid evidence to support this is an actual issue (in humans vs. rats)? If you were to cycle off the ketogenic diet, would it be best to lower the amount of fat intake as you slowly raise the carb intake? Perhaps the Mediterranean diet would be a good example of a lifestyle diet to transition to. Would you recommend that?

    Do you have any suggestions on how many carbs are too many when cycling back towards more carbs? For example, if you are ingesting 50 grams or less a day with ketogenic and you transition to no more than 150 carbs a day. Would you say the best long term lifestyle is a cyclical diet to improve overall health and performance such as utilizing ketogenic diet, intermittent fasting, and/or increasing carbs again? In your expert opinion, what does that look like? Thank you for taking the time to answer any of these questions. I appreciate all the work you have done and continue to do to educate people on nutrition and health.

  • Abarm D Patz

    After reading this article I purchased a blood ketone/glucose reader. You stated that you consider above 1mM to be in ketosis and my reader states that I am 1.2mmol/L. I was wondering if mmol/L is the same as mM? Am I in a good ketogenic state for weight loss or can I do better? I currently consume 117g protein and 34 grams total carbs daily. Do I need to lower my carbs further or am I okay where I am at? Thank you.

  • Tomica

    Hi Peter,
    Ive read all your blog a couple of times in the last 2 weeks, since Ive started to live on LCHF principles and wanted to get in ketosis. I still am not sure that Im in that state, so the ketones meter is ordered and cant wait for the first results.

    But in 2 weeks I have a trail race of 65 km and I would like to hear your opinion about one thing.

    Ok, lets say that I will be in ketosis in 2 weeks but would also like to have full glicogen rerves for the toughest part of the race, will eating, 2 or 3 days prior to race, sweet potatoes to load on glicogen get me out of ketosis for the race or will my body burn primarly fat and use glicogen only for the hardest parts?

    Sorry if its a dumb question but I couldnt get 100% positive conclusion by my self 🙂


    • 1. ALL of them?!
      2. I would never recommend a dietary shift 2 weeks away from a race. Assuming ketosis is optimal for you, I wouldn’t bet on such a quick adaptation.

  • Garrafa

    Very nice question but very bad developed. At the end. it is possible consume half the day the carbs the body has and when it finishes take fuel from ketones? The question still remain….

  • Adi

    Hi Peter!
    I like your blogs and bodcasts even as an (lacto-) vegetarien! So its hard to get in ketosis only by nutrtion – combined with IF an endurance training after the last meal a day its possible. I’m an cyclist (my level is not a bad age grouper)!
    I also tried KetoForce and Superstrach – first time using KetoForce before practice under lab-condition (indoor-cycling on a track) there was incredible results by performance, feeling and recover – i combined with MCT-oil during the practice – i also tried outdoor, there its not so easy to say smoething objectiv – but still feel something – it is close the same by using SuperStarch.
    Now i got KetoCaNa – what do you think about blend it with SuperStarch?
    Would be happy for some comments and/or suggestions for differnt use!

  • Marc

    Hi Peter

    Great site! I have a quick question about ketosis and heart rate. I have been on ketosis for a few months and notice the following with my 4 minute intervals pre and post ketosis:

    – Breathing is less laboured (I understand that – more efficient use of Oxygen)
    – slightly less average power (I understand that too)
    – Increase in average Heat rate by about 5 beats per minute

    Another way to look at it is that my heart rate has increased for the same power. This one is a mystery to me. I’d be surprised if heart volume suddenly changed, which would imply that oxygen demand is not the only parameter. Do you know what other substrates are being measured by the body to regulate heart rate?

    • Impossible for me to know without metabolic testing, but volume depletion would be first guess. Less volume means less pre-load in the heart means less contractility means higher HR for similar cardiac output.

  • Name

    A nitpick from someone coming from hard sciences a bit anal about proper abbreviations: change gm/day to g/day in your posts. 🙂

    Definitely not the most important, impactful thing to do, but it may make some people unnecessarily cringe, and I suppose it’s an easy enough find-and-replace job.

    Thanks for sharing all that, looking forward to see the NuSI data.

  • Hi Peter. I am very intrigued by your blog, your research, and all the work you are doing. Your TED talk was phenomenal, and it shows what a personal connection and commitment you have to breaking down the barriers and assumptions that stand in our way to becoming healthy as individuals and populations.

    I recently started Boundless Health, a Health and Athletic Performance center in Solana Beach. One of my associates, Dustin Schaeffer, is part of the team rolling out a new ketone supplement to the market. The formula was develop at the University of South Florida by Dr. D’Agostio and his team. The Keto – OS product is equivalent to 1/2 dose prescribed to the Navy Seals by Dr Dom (with less GI side effects). We find that within 60 minutes of the Keto – OS we will see a .4-.9 mM increase with one serving.

    We have seen some amazing results of the last six weeks and we hope to gather data that would add to the growing literature on ketosis for health/athletic performance. We would love to learn more about your experience and open up a working dialogue with you. I know you are a very busy man, but if you have any interest, please contact me at

    Thanks again for all your work and your commitment!

    Bret Scher, MD FACC

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  • Tyler

    Hi Peter,

    You mentioned that after your bike rides, your body prioritizes glycogen replenishment AND promotes insulin sensitivity. I was curious to know if you have determined how long this physiological state lasts for you?

    Keep up the hard work!! Truly an educational blog!

    • Probably depends on the individual and the type of exercise.

  • Ricardo Vilá

    I hopefully will make Ironman Maryland on October 3. Have been trying your diet recomendations for last 3 weeks. I am beginning to see great results in everyday life, in swimming and cycling. But since I begin this diet, long runs have been a disaster. Slow running, and stomach pain that stops as soon as I walk. Any advise? I use to fuel long runs with Ucan, X2 performance, coconut oil and MAP. Today I try at first with nothing more than water and electrolytes (first hour and a half, no stomach pain but very slow), then with raisins, and the stomach pain appears again. My next move will be trying with cocunut water.

  • Ricardo Vilá

    I know there is an adaptation period that can last for months. But do you think it can take longer for example for running than the other two disciplines? Do you think that the stomach pain while running is diet related?

  • John

    I learned from your very informative/interesting blog that the body prioritizes carbohydrates to replenish glycogen stores. To support weightlifting (hypertrophy and strength training), could I take maltodextrin with whey protein during my post-workout in order replenish my glycogen stores in my muscles AND spike insulin (stimulate anabolism), without kicking myself out of ketosis?

    I learned from your Super Starch video that insulin levels affect fat oxidation.

    It sounds like Super Starch can be used to achieve glycogen replenishment, but I’m wondering if I can benefit from insulin spikes post resistance training, and still benefit from that steady energy state of ketosis outside of this meal timing.

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  • Guillaume

    Hi Peter: You wrote “I use the Abbott Precision Xtra meter”. I want to buy such a meter but wanted to know if this is still the one you would buy if you were to get one today, or if you would recommend something else? Thanks

    • Guillaume

      And I’m also wondering if you looked into insulin meters and continuous glucose monitors. C8 Medisensor (using non-intrusive Raman spectroscopy to precisely measure glucose from the surface of the skin) looked very promising, but they just disappeared from the market, even after opening up for pre-ordering (which I did). Maybe you are aware of other similarly modern and intelligent meters?

    • I haven’t been following the technology, so others might have a better response. It may come down to strip cost.

  • Bob

    I am trying to experiment with a nutritional state of ketosis., however I eat foods high in fiber. If I am calculating carbs as carbs minus fiber, how many net carbs should I aim for in order to get in a state of NK?

    I believe I am prone to insulin resistance and diabetes runs in my family. Would eating foods high on the glycemic index but that have low glycemic loads (carrots, beets, etc.) cause weight gain in someone with with an insulin resistance profile. Additionally would these foods disrupt efforts to get in a state of NK?

    • Karen

      Im no expert but from what I read I would go strict low carb for 2-4 weeks until you’re in nutritional ketosis (blood markers 1.5-3) Then slowly add low glycemic loads and test your ketones. If you can stay in ketosis than your good if you can’t than you know you cant…that my thought anyway. Good luck!!

  • Karen

    Hi Peter,
    I started a low carb, high fat diet over a month ago and thought I did all the research I needed to before jumping in. The last two and a half weeks my ketones have been between 4.4 and 4.7 on my blood ketone monitor however I haven’t lost any weight. My blood has been stable between 60-70. I eat two large meals a day. One at 1pm and the second one at 6pm. The total calories are about 2000 per day. I enter my meals in MyFitnessPal and it seems that my fat is about 75-80% and carb 5-12% and protein 10-15%. I do drink coffee and eat dairy….should I be patient and keep going the same route or do I need to give up something ie dairy or coffee? Seems strange that my ketones are so high but not losing weight?

    • JS

      Your carb and protein shouldn’t be a percentage but a constant number. 10% of 2k is 200 and it’s too high unless you have a really high lean body mass. So for example, I try to stay 30 to 50g carb, 100g protein. If I require a high calorie intake for let’s say.. an endurance workout, the only thing that changes is the fat. Peter Attia explains this although I can’t recall the link.

  • Dougue

    I’m struggling with this one Peter……can you explain glycogen debt/deficit?
    And what do you mean about the “2 errors” athletes and non-athletes make (overestimating need for carbs and nothing influences RQ more than dietary composition)?
    And finally, when you say you were able to stay in ketosis after your daughter’s birthday, was it just coz your were able to shunt all that glucose into muscle cells from being much more carb tolerant/insulin sensitive after a massive workout?

  • Markus

    Hi Peter,
    great work, love your blog and take a lot of inspiration from it. Just started NK and did a VO2MAX test – inspired by your other article. I am building up for the Taupo Ironman in New Zealand 2017. I always have been a good fat burner but my VO2MAX showed extremely high fat oxidation numbers.The main credit for that goes to Dr. Phil Maffetone and his holistic training philosophy but I think NK had a big part in it too. All of your blogs about athletic performance are excellent regarding the nutritional part of it. But the way we exercise has a huge influence on carb / fat burning too and I wonder why you leave that out? What I have observed in my own training and my friends training is this: If we train above FatMax (Aerobic Threshold) and burn more carbs than fat out cravings for carbs increase. I know many very active cyclists that ride more than 10 hours per week but still have more than 20% body fat. One of the main reasons, in my opinion, is that they ride too fast. Anaerobic training and fat burning don’t match well.

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  • maria

    I found your blog seraching the internet looking for answers…Your speech about the lady in the ER with the foot amputation hit home for me on so many levels. Both my grandfathers and my father were diabetic (type 2). I recently found out i am insulin resistant, this all makes sense to me now since i haven’t been able to loss weight in a very long time. I too am very active, working out 5 days a week and eating very healthy. Once i found out i am insluin resistant i decided to follow a very low carb diet with the guidance of an RD, but still no weight loss results, it has been six weeks.
    My goal is 25% body fat, currently i am about 32%. All my blood work is good and within range except for my LDL is a little high. The blood test showed my body produces cholestrol. I check my urine ketones a few times a week for the last four weeks, they are always trace to small, never moderate. I have scaled down my workouts, per my doctors orders, thinking my body is over stressed. My gut is telling me the insulin is preventing me to loose the extra fat, Can you give me a advice? Help…Thank You!!!!!!!!

  • Tamara

    I am not sure you will see this comment, as it comes so late after the original post but I HAVE TO ASK—–can you please share your hummus recipe?? 🙂

  • Su-Chong Lim


    I am a relative newbie biker, but in trying to parse all the moving parts, given that following an exercise induced glycemic debt, it seems that you now have the choice of administering carbohydrate to replenish your depleted muscle glycogen without compromising your ketotic state, or NOT replenishing your muscle glycogen by administering carbohydrate, or perhaps only partially replenishing.

    The reason I raise the question of reasonableness of choice is that I note that part of the price for “carbo-loading” is that with the full load of glycogen replenishment you also get an 8 pound obligatory water load to go with it. In the old (high carbohydrate diet) days of simplistic refuelling theory my choice would have been obvious — muscles can only function on glycogen, so it must be replenished. Now, with my more nuanced understanding of the flexibility of fuels for a ketotic athlete, I wonder if your choice might be affected by the nature of your ride tomorrow. If it was to be a largely flat course, then go for the CHO loading. But if a lot of climbing was involved, would it be reasonable to consider NOT CHO-replenishing, given that weight is a huge performance penalty in climbing?

    Certainly, from the running perspective weight is a penalty even on flat stretches, so I am grappling with this equation. (Life was so much easier when there was only one principle — “Carbo Loading Is a Good Thing”).

  • Su-Chong Lim

    Oh, supplementary questions: Regarding the Abbot Glucose and Ketone meter, somewhere buried in the myriad answers you let drop that you buy the blood strips “cheaply, in Canada”, and keep on the lookout for bargains. Leaving aside the observation that something marketed in the US may be found cheaper in Canada is an anomaly, where do you get yours? Are we limited to using Abbot brand, or are all the advertised strips chemically equivalent? Do you have any current feedback on the reliability and usefulness of the exhaled breath acetone analysers?

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  • Su-Chong Lim

    OK: Here’s a data point from my own N of 1. I just did my first 10 k race of the year, a course that I’ve regularly done early in the season in 44 minutes plus or minus. Last year I did it in 43:40, a best in 6 years despite creeping age lol. However, I am actually trying to optimise for an Ironman in August. So I have been more or less high fat low carb for a year, and I suspect I have been on the cusp of ketosis or actually in ketosis intermittently for a year while training fasting in the morning for 2 hours before bacon and eggs and sardines breakfast. But since finding this blog and clarifying on the science this past week, I have been more precise, and I estimate I have been below 30g CHO daily. Now I’m only 51kg, so maybe that’s not low enough for my per kg calculation, but I don’t know. A knowledgeable endurance competitor and coach suggested I carb up “slightly” because the 10k race is a somewhat higher intensity effort than the 3 to 6 to 12 hour races I am primarily aiming my diet for. However, I feared that whatever carb overload I prepped myself with would cause a glucose spike as it drove glucose into muscle and liver, and through the insulin response turn off my ability to oxidise fat, leaving me with the worst of both worlds — not enough glycogen for a full out effort, and without any back-up ability to metabolise fat. So I declined, and did not carbo load at all, keeping to my same old low carb diet till the night before, and not eating a breakfast before the race,

    This morning’s race started ordinarily enough, but by 3k I noticed my k times were slipping and by 5k there was definitely a time deficit relative to what my training normally would have predicted. By 7, 8 and 9k I was slowing down despite considerable puzzlement and trying to force the pace. My eventual time of 47:20 was despite optimum effort, and usual attempted sprint at end, and complete exhaustion at the finish line.

    So, what went wrong?

    Possibly my last 2 weeks of strict CHO restriction to 30g was the first time that I was consistently in ketosis, and I was not yet fully keto-adapted?

    Or would even full keto-adaptation only allow for a maximum rate of fat oxidisation that delivered less power than the full power I was used to producing in a 10 k running race (on my prior high CHO diet)?

    If the latter situation is true, is there a way to CHO load without prior maximal exertion and glycemic debt, which might not be prudent the day before a 10 k race, and still not shut off the capacity to oxidise fat (i.e. ideally provide for maximal glycogen burning and simultaneous muscle fat burning at high rates).

    There may be other possibilities for the mismatch in expectation and performance, but I can’t think of any other. I followed my usual training protocol, with typical speedwork and appropriate tapering of volume. My legs are pretty sore as would be expected after a maximal effort.

    It’s a pity I didn’t verify that I actually was hitting ketosis, but I wasn’t getting hungry when meals were due, and subjectively I was feeling ok, despite intensive exercise during morning fasting, so my educated guess is that I was in ketosis.

    I have just borrowed a ketone/glucose meter tonight and will start checking tomorrow. Very Interesting.

  • Su-Chong Lim

    After 2 and a half days of frequent checking blood glucose and ketones, as I suspected, I was continually in the lowish (compared to “normal”) glucose range, 4.4 to 5.4 mM (multiply by 18 to get mg/100ml) and BHoB 0.4-0.9 mM with spikes to 1.3 after exercise. Whether that has been in place for a year or only been going on for 2 weeks is another matter.

  • Su-Chong Lim

    Tracking glucose and BHB fairly closely this past 10 days, apart from the expected ketosis results sometimes, I have noticed some anomalies that I can’t explain. I initially thought there might have been instrument artefacts, but the same pattern has happened on several occasions. Essentially the anomaly is sort of high in the evening, low in the morning, then rises during exercise. (On other occasions, glucose drops as expected with exercise and BHB rises).

    Last night at 11 I registered a rather high glucose for me 6.1mM about 5 hours after I ate about 130g of pork, say 25g protein and a small slice of chicken pie, say 15g CHO in the crust. I had only coffee with cream 2 bacon 2 eggs and a can of sardines that morning, no CHO. I’m about 51kg body mass.

    This morning at 8:20 my fasting glucose was 4.6. I didn’t eat and ran 16.3k, doing the last 2k in a sprint, taking 90 minutes. Immediately after this my glucose was 6.1, despite exercise and no intake. BHB remained low at 0.3 as expected with this high glucose level.

    The only explanation that I can think of is that my CHO intake may have drifted slightly above my arbitrary 15-25g limit between 2 and 3 days ago (I’m experimenting leading up to a Half Marathon). But subsequent morning fasting glucose levels were suitably low again.

    Perhaps a “suitably low” glucose level in the morning may be the result of a glucose spike during the night with an insulin surge?

    But it is hard to see why I would have had much of a glucose spike last night, unless I am grossly underestimating the CHO in a small wedge of pie-crust.

    And after an initial reading of 4.6 this morning, where did the glucose come from to give a reading of 6.1 after exercise? Liver Gluconeogenesis? Maybe the glucose level dropped so low during exercise (I wasn’t feeling particularly great, but I didn’t notice any shakiness) that there was an epinephrine surge? And if this was the mechanism, wouldn’t some fat mobilisation have occurred? Or does BHB take several hours to show this? (I have had my BHB rise within 1.5 hours of exercise on other occasions). Teasing out this CHO/exercise, glucose and ketone dance is indeed a puzzle.

  • Su-Chong Lim

    Don’t want to drag this out unnecessarily, but surprises continue. Immediately after this morning’s post-run Glu=6.1, BHB=0.3 I ate a modest meal with about 8gCHO. 8 hours later, with no further food intatke, Glu=3.8 and BHB=2.6. If there is a pattern here it may be that BHB takes several hours to rise. Maybe acetoacetate was high or rising initially, but BHB at that time had yet to rise (from acetoacetate transformation). But that still doesn’t explain the glucose rising during the (fasting) exertion of the run.

  • Madalyn

    Such a fascinating topic! Thank you for sharing this info.

    I am currently 36 weeks pregnant and have been testing positive for ketones in my morning urine for the last few weeks. I do not have Gestational Diabetes. I have tested my blood glucose consistently over the past few weeks and, if anything, tend to have lower glucose levels (although I am not technically hypoglycemic). There is so much information on the web about how dangerous ketones are during pregnancy, but much of this connects ketones to GD. After reading your blog, I am inclined to say I am experiencing nutritional ketosis and not diabetic ketosis.

    What I find puzzling about my ketone situation is that my weight gain and diet have been great. I have gained about 40 lbs in my 36 weeks, so why would my body be so quick to enter ketosis? I eat a solid snack before bed, but will test positive for ketones a mere 6 hours later… How can weight gain and ketosis co-exist? Obviously some of this weight gain is baby, placenta, fluid, etc, but certainly some of it is fat.

    I feel very healthy and have tons of energy, so I am not particularly concerned about the ketones. I am just curious about what is happening in my body.

    Your thoughts would be much appreciated!

    • Rick

      I’m not an expert, but have heard from others more knowledgeable than me that babies are in ketosis in the womb. So the ketones in your urine could be from the baby since you are peeing for two 😉

  • ydanis

    I’m a type 1 diabetic and find when I exercise my glucose levels rise 2 hours after exercising and morning glucose levels are high about 170. Do you have any explanation for this and how to avoid the high glucose levels? Thank you!

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  • Nick

    Stumbled across this article by chance. Well written, and does seem to confirm what I’ve been seeing with my own workouts. I’ve tried CKD and SKD before, and after a week or so I’d just end up obliterated, so I’ve been trying TKD. People were recommending to consume between 20 and 50 carbs total pre and post workout, and I’ve been noticing that even when I’m around 50, I’m ending up in a keto state less than an hour or two post-workout, and my energy was still low. I then upped it to 100, and I’m still back in ketosis quickly. Guess I’m just gonna keep experimenting with increasing it (to the point where the calorie total doesn’t damage my other macros), and this is only with an hour and a half of weightlifting and 30 minutes of HIIT.

    One thing I’m quite curious about is how much genetics affects the sensitivity to carbs and maintaining a keto state. I know some people can’t even exceed 20 on workout days, and it seems that’s just nowhere near enough for me.

    Thanks again for the article!

  • Brian

    What are your opinions on the Cyclical Ketogenic Diet? Adapting to keto than lets say for one day every 7-10 days loading moderatly (not binging) on glucose generating carbs, so no sugars, no fruit, just bread, rice, yams?

  • Eliseu

    Dear Peter.

    Great articles! Yours were the only I found that dived into the chemistry of it all. Congrats!

    Well. My question is really simple, but none has answered it yet.

    If I am supplying lots of fats to stay in ketosis, why would the body burn my own fat? Why would I loose weight if I can eat fat in an unlimited manner.

    Thank you.

    • Not clear it will in the case of “lots.” See the post on fat flux.

  • Balu Nadiga

    Dear Peter,
    Loved your article and how you go about all this! One question: What are the time scales of “glycogen deficit/debt?” Meaning how soon is the deficit made up by the body through gluconeogenesis and lipolysis if I don’t consume carbs within that period. Practically, it amounts to: Since I love carbs and am brand new to experimenting with ketosis (because of metabolic-syndrome like presentation: lean but high triglycerides, low HDL), if I accumulate a (an even small) glycogen deficit or debt, how long do I have to indulge in my favorite carbs? Common-sensically, I’d think an hour or two, but I’m sure you have a biochemistry and evidence-based answer. I realize this could get complicated, e.g., from its dependence on the magnitude of the deficit or debt etc…, but I’m sure your answer will be insightful. (if necessary you could assume the deficit as arising from a 1000 kcal effort starting with no deficit while in NK.) This would be very helpful in hacking NK to satisfy my own carb-cravings and, like you, give my wife a break from the NK-nonsense

  • Ginsling

    Just a general comment here because my diet is little like your experiments with yourself. I work hard to hit my protein intake as my single biggest dietary goal (1.00gm / kg bodyweight = 53gm / day) with nuts, legumes, green leafy veg, salad, eggs etc, before adding in fruit and yoghurt, occasionally cheese. The only fat I take in is in what’s contained in those ingredients. I don’t do alcohol and coffee.

    I’m in a keto state generally (based on RER measurements – .64) and even at a V02 max (peak) don’t hit 1.00 (only .94). I train long distance running. I don’t use ketone measurements because I don’t vary my diet (even for my daughter’s birthday).

    Perhaps my consumption of legumes etc prevents a keto state and I just happen to be in it when I do V02 max tests (or RQ, RER is a poor measure). But being able to run several hours and not eat, or feel hunger, would also tend to suggest that I’m fat-adapted.

    It’s not only a high fat diet that will attain this state.

  • L.Michael McNab

    Dr Attia – I’ve encountered your blog here only tonight – you are a sheer pleasure to read. Love your geeky mix of discursive observation with apropos, deep insightfulness. Please carry on!

  • Marc

    Hello Peter, I’m running on Ket for the last 3 weeks. kindly inform me what I should have during extreme sports like XC MTB racing for around 3 hours….

  • Sharon

    Beginning a Ketogentic style of eating, and starting to train for a half marathon. Can I use one scoop of UCAN before my runs starting out until I am keto-adapted? Or will using UCAN in the early stage keep me from being keto-adapted?

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  • Carol

    Dear Dr. Attia, I have a question that maybe only you can answer, being that you have studied the topic closely and have done more self experimentation than just about anyone. I follow a ketogenic diet much (but not all) of the time. Normally my fasting glucose is 95, consistently for several years. Recently I went to the ER with what turned out to be a kidney stone (my first). By the time I was seen I had been in severe pain for 3 hours. I had fasted that morning. My blood test revealed positive ketones (2+) and glucose 142. Now my PCP says I am diabetic. I asked her whether being in severe pain would drive up the glucose. She says ‘no’. Is it possible that I have suddenly become diabetic? It seems more likely to me that the severe stress is what drove up my glucose: fight or flight! I appreciate your comments. I have searched the internet for clues about this but have come up empty.

    • What? Of course severe pain–or any physiological stress–can and does drive up glucose. Stress –> cortisol –> hepatic glucose output –> higher blood glucose. I’m sure (I hope) your PCP just misunderstood your question.

    • Carol

      Thank you very much for your response! She was not answering a question, actually. She was looking at a lab report and telling me her interpretation/diagnosis. I was very surprised that she concluded that I was diabetic based on a single lab, and especially under the circumstances. Since then I did a self-experiment: 3 reasonable meals spaced evenly throughout the day, 16 glucose measurements, and I am happy to say that my glucose response is perfectly normal, starting at 90, maxing out at 148 after dinner and returning to baseline within 2 hours consistently. I hope she will learn from this not to alarm a patient unnecessarily, but I am concerned that she would jump on a diagnosis like that.

  • Patrick Salmon

    Hi Peter. I have tested exercise after 2 to 4 days of fasting (just water plus electrolytes). My blood glucose is stable around 3.5 mM. Then, I resume eating with LCHF (less than 50 g of carbs per day, and on day 4 my blood glucose is back to 5 mM. Am I still is ketosis? (I did not check for blood ketones). Should not my blood glucose stay in the 3.5 mM range after fasting and LCHF? Thanks for your feedback. And BTW, your site is really precious.

    • Blood sugar isn’t sensitive enough to predict magnitude of ketones in blood.

  • Alai

    Hi Peter,
    Very intersting information. Thanks for sharing.
    I have recently changed my food habits (5 weeks) right after the Boston marathon. I have cut the carbs to 50g a day and increased the fat intake to 200g a day. When i measure my ketones i’m between 0.6 and 1.1 using novamax.
    My question: i do not seem to be able to recover from the Boston marathon where my legs are still heavy and my muscles are still sore. Usally it takes me 2 weeks to recover from a marathon. I’m wondering if this inability to recover is related to my adaptation (or lack of) to a high fat low carb diet. I have reduced my training and removed the intervals in the hope of recovering but I do not seem to Recover. Your thoughts would be appreciated. Thank you

  • Bob Lamb

    I’m an IF dieter (16:8 to 20:4) and also will sometimes go low carb for breakfast and lunches when I eat them to maintain weight. I run 3xweek and lift 2xweek. I’ve found I can do a lot of physical activing taking the UCAN SS when working out while fasted and not have any GI issues also. You still use the stuff?

    • I do still use UCAN SS for meal replacement shakes from time to time (incl yesterday!).

  • There is now starting to be a flux of extrogenous Ketones available on the market that claim to get you into the state of ketosis. I know personally I benefit from them with endurance activities, but do they actually put you into a quick state where you burn your own ketones (or fat) for fuel?

    Thank you

  • Ramy Gabr

    Hi Peter,
    I was wondering what is the benefit of MCT oil then with high carb/ high protein diet. I am doing weight lifting and cross fit and would eat around 300gm of complex carbs over the day to gain mass but cut fats at the same time, but I am for sure wouldn’t be burning as many calories as in your extreme example where you consumed 321gm of carbs.
    My nutritionist advised me for MCT oil, and I am trying to relate it to ketogenic state, but can’t get it. Or perhaps it is for another purpose that I am not aware of.
    Do you have any thoughts? any benefits from having MCT oil with high carb diet?


  • Ulq

    Hi Peter, I discovered your blog recently and I wanted to thank you for your clear articles. I’ve got a few questions if you don’t mind:
    I don’t need to lose weight, but I wanted to try a moderate LCHF diet because it seemed mostly beneficial, and I’m quite looking forward to stop being an addict to sweet things. However, as I’m still a student and I don’t live independently, I cannot always eat what I want. I wanted to ask you if following a LCHF diet when I have to eat two or three high-carb meals per week is fine or dangerous, as I’ve read that high carb intake added to high fat intake is a very bad option. Particularly, I often eat Asian meals, so there’s either rice or noodles in them.
    Also, I’ve tried to search the web for the impact of fruits in LCHF diets, because I find it a shame to give up on many fruits, and I’m not sure to understand whether fructose is okay or not. What is your opinion on this?

  • Rory

    Hi Peter
    I have just subscribed and am finding the content of the blogs extremely interesting and educational.
    I’m a relative new comer to the concept of the KD and NK and have been adapted to it for about 3 months now.

    I’m a competitive open water swimmer and looking to try and combine the benefits of having glycogen stored in the muscles and also access to fat stores for sustained pace over a race (1.5km-2km). My calorie requirements for this is roughly 500kcal to 700kcal.

    From reading your article ,is my understanding correct that you were able to enjoy the benefits of using both ketones and glycogen by drip feeding carbs during during the activity?
    If this is the case can this be done in open water swimming, as the only opportunity you would have to take in the carbs is before the race, however I would think this would spike insulin and hault the production of ketones?

    would another viable option be to load up on some carbs two days before a race, just after training, then fast the following day to get back into ketosis for a race the day after fast day? I have never tried this but I am contemplating it, but at the same time I don’t want to mess the progress I have made thus far?

  • Pingback: 12 Simple Solutions for Triggering Ketosis()

  • MidwestGal

    Interesting article. When I first started ketosis, I was able to get a blood reading as high as 1.1, and by first started, I mean in the first week or two. Since then, I’ve been lucky to hit 0.4. Usually my meter just reads “low” (which means less than 0.1). I keep my carbs to less than 50 total, and often less than 25 total. My protein is 80-100g. My fat intake is 100-120g. I bike, run, and lift weights 6 days a week. My body just doesn’t produce excess ketones. I make just enough to use I guess. My blood glucose is always upper 70’s to lower 80’s mg/dL (I’m not diabetic). I’m not sure why high levels of ketones in the blood are important.

  • CGM to measure. Optimization is context specific.

  • I wrote about my experience here:


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