August 26, 2013


Ketones and Carbohydrates: Can they co-exist?

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

Read Time 8 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

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  1. 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.

    • 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…

  2. Peter,
    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.

  3. 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).

    • 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.

    • 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?

  4. 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.

    • 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.

  5. 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???

  6. 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.

  7. Peter,
    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.


    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!

    • 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

    • Luca,

      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).

    • 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.

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

      • 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?

  10. 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?

  11. 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.?

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

    • 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.

  17. 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)?

    • Peter!

      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! 🙂

  18. 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).

    • 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.

    • 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.

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