March 7, 2012


The interplay of exercise and ketosis – Part I

by Peter Attia

Read Time 7 minutes

I embarked on a self-experiment last weekend to see if I could better understand the interplay between the different types of exercise I do and ketone production (beta-hydroxybutyrate, or B-OHB, to be specific).  To be clear, nothing I do with a sample size of one “proves” anything, but sometimes self-experiments can help you formulate hypotheses and, if nothing else, understand how your body works.  Consider the parable of the black sheep.  If you see even a single black sheep in the field, depending on your field of training, you can draw conclusions:

Three scientists were on a train and had just crossed the border into Scotland. A black sheep was grazing on a hillside. The biologist peered out of the window and said, “Look! Scottish sheep are black!” The chemist said, “No, no. Some Scottish sheep are black.” The physicist, with an irritated tone in his voice, said, “My friends, there is at least one field, containing at least one sheep, of which at least one side is black some of the time.”

My point is, even a self-experiment of one can be good for something.

To test the relationship between exercise and ketosis I decided to examine my blood levels of glucose, B-OHB, and lactate immediately before and after three different types of workouts on three successive days.  This interplay is complex and no one knows “everything” about it, including the world’s experts (which I am not pretending to be).  I’m going to try to balance a fine line in this post – I want to be rigorous enough to explore the ideas with substance but not too detailed to put you to sleep.  I hope I am able to balance these forces adequately.

If any of you are not familiar with the work of Jeff Volek and Steve Phinney, but you are interested in the biochemistry of nutritional ketosis, I recommend getting familiar with their work.  The list of people who know more about nutritional ketosis is short.

Let’s take a look at the three parameters I measured in a bit more detail.  To give you a sense of what is “normal” here are some guidelines:



A normal fasting glucose is generally considered to be between 75 and 100 mg/dL.  My mean over the past year has been about 90, but I need to mention two very important caveats:

  1. On the four occasions I have calibrated my hand-held device with an actual laboratory test, my device seems to run high by about 11 mg/dL, so a measurement of 95 mg/dL on my device is probably closer to 84 mg/dL in reality.
  2. I carry a genetic trait for a disease called beta-thalassemia.  The clinical manifestation of this is that I have much smaller red blood cells than normal (about 65% of normal size).  There is some evidence in the literature that this condition prevents some accurate testing of any assay that can interfere with hemoglobin.  For example, a test measuring glycosylated hemoglobin suggests I have much more glucose in my blood than is actually measured. In fact, the Glycomark test for mean post-meal glucose level suggested I have an average post-meal glucose level of 190 mg/dL which is obviously not true.  In other words, something about my beta-thalassemia seems to interfere with, at the very least, measuring glucose linked to hemoglobin, and possibly measuring glucose in general.

I mention these 2 features to say my glucose levels (unlike B-OHB and lactate which I’ve documented to be very accurate) may be artificially elevated. Here’s the important part, though: the discrepancy seems to be constant, so the increases or decreases seem to be good measurements.

Beta-Hydroxybutyrate (B-OHB)

A normal fasting B-OHB level for a “normal” (i.e., non-ketotic) person is zero.  Within a day of fasting, you might expect this number to reach 0.2 to 0.4 mM, and about 1.0 mM within 48 to 72 hours of complete fasting, though this is highly variable among subjects.

If you’ll recall from my discussion of keto-adaptation, the threshold for nutritional ketosis is about 0.5 mM.  My normal morning fasting level of B-OHB is usually between 1.0 and 2.0 mM with an arithmetic mean of about 1.4 mM.

Both insulin and glucose (probably by causing the secretion of insulin) suppress ketones. This is why, for example, consuming more than about 50 gm of carbohydrates per day and/or more than about 120-150 gm of protein per day makes it difficult to be in nutritional ketosis – too much insulin secretion.



Lactate (or lactic acid) is a byproduct of anaerobic exercise.  A normal level is considered to be below 2.2 mM.  Basically (I’m oversimplifying a bit), when you exercise in a predominately aerobic capacity, while you do generate lactate your liver is able to match muscle production with clearance via a process called the Cori Cycle (a process in which the liver turns lactate back into glucose).

If you’ve ever done a very intense exercise – like run an all-out mile – and felt like your body is completely seizing up and you are unable to move, you’ve experienced a high lactate.  Technically, the lactate is not causing this.  Lactate gets a pretty bad rap, and it’s actually a good thing as it allows us to generate energy even when we demand it in an environment where sufficient cellular oxygen is absent.  The real “bad guy” is the hydrogen ion that accompanies lactate and interferes with the ability of our muscles to contract and relax properly.  However, we use lactate as a proxy for the hydrogen that is actually causing the pain and difficulty in muscle contraction.

For me (personally, though this is probably true for most people) the highest lactate I generate tends to be in all-out activities lasting about 2 minutes which use all muscles in my body (the more muscles you use, the more lactate you generate).  Hence, the 200 individual medley (IM) race generates the most lactate in my body: It’s 2-plus minutes of maximum exertion sending pain into every muscle in my body (this event requires a swim, in order, of 50 yards each of all-out butterfly, then backstroke, then breaststroke, then freestyle). A runner would probably concur that the 800 meter (half-mile) run is one of the most painful races in that sport.

The highest lactate I have ever measured in myself, following a 200 IM race, was about 16 mM.  I have measured higher levels in several Olympic swimmers, including 20.2 mM in one (as he was vomiting all over the pool deck – for reasons I’ll try to remember to explain in a subsequent post). On my bike, where I’m mostly using my legs, obviously, I think my highest recorded lactate measurement was about 12 or 13 mM following a set of ten 2-minute all-out hill repeats.

I measure my lactate levels using a different hand-held device from the one that measures glucose and B-OHB.

[Another parable, this time about marriage: 2 years ago my father asked me what my wife and I wanted for Christmas.  I said “we” wanted a lactate meter with about 200 test strips (I think it was about $900 for everything).  He looked at me funny, but figured I knew what I was talking about.  When Christmas rolled around and “we” got “our” lactate meter I had to spend a few minutes explaining to my wife why this was a perfect gift for “us” as it allowed “us” to spend lots of time together while she pricked my finger for blood during my workouts.  She didn’t really agree with me.  I clearly don’t understand women very well – I really thought she would find this device “cool.” Which is why this is a blog about health, not marriage.]


Results from my experiment


Day 1: Saturday (hard swim workout, race pace)

This was a one hour, 45 minute swim with warm-up and cool down.  The “main set” was mostly freestyle and butterfly at all-out race pace for distances of 25, 50, 75, and 100 yard intervals with long rest (1:2 – 2 times more rest than swim time) for the all-out 100 yard swims, and modest rest (2:1 – half the rest time of each swim).  The single most demanding aspect of this workout took place with about 25 minutes remaining and, though I didn’t measure peak lactate, I suspect it was around 12-14 mM, based on the discomfort I experienced. I was surprised that my lactate level was still as high as it was (see below) 25 minutes later, though I suspect I didn’t cool down as gingerly as I should have, to optimize for maximum lactate clearance.

During this workout I consumed nothing and prior to the workout I consumed my usual 40 mL of medium chain triglyceride (MCT) oil.

At 7:29 am, just before beginning the workout, my glucose was 86 mg/dL, B-OHB was 0.7 mM (which is low for my fasting level), and lactate was 1.9 mM.

Immediately post-workout, at 9:14 am, my glucose was 118 mg/dL, B-OHB was 1.0 mM, and lactate was 7.2 mM.


Day 2: Sunday (long ride, 80% of race pace)

This was a tempo ride covering 104 miles (167 km) with 5,600 feet of climbing.  Average pace was 17 mph (about 28 km/hr) with lots of headwind.  My average HR over this 6 hour ride was 141 and average power output was between 190 and 200 watts.   There were many sections of the ride, particularly on the climbs, where my HR was sustained in the 160’s for 30 minute stretches and power output was above 275 watts (which, for me, means my muscles generate lactate faster than my liver can clear it).

During this workout I consumed the following:

  1. Two single-serving packets (1 oz) of cream cheese (14 gm fat; 2 gm carb; 2 gm protein)
  2. 50 gm of super starch, by Generation UCAN mixed in my water bottles (50 gm super starch which, technically, is a carb but does not behave like one with respect to insulin secretion and ketone suppression – I will write a dedicated post on super starch in the future, but if you must try it now, use this code to get a discount: “UCANPA”)
  3. 2.5 oz of mixed nuts (25% of each almonds, cashews, walnuts, peanuts – 36 gm fat; 14 gm protein; 15 gm carb)

Total intake during 6 hour ride, therefore, was: 50 gm fat; 16 gm protein; 67 gm carb (of which 50 gm was super-starch), for a total of about 750 calories.

About 90 minutes prior to the ride I consumed 4 eggs fluffed with heavy cream, cream cheese, coffee with heavy cream, and my usual 40 mL of MCT oil.

At 7:56 am, my glucose was 88 mg/dL, B-OHB was 1.3 mM, and lactate was 1.7 mM.

Immediately post-ride, at 2:39 pm, my glucose was 74 mg/dL, B-OHB was 4.4 mM, and lactate was 2.2 mM.


Day 3: Monday (dry-land, high intensity training)

On this particular day, it was raining (one of 3 days a year this happens in San Diego), so I did not do the outdoor stuff (including tire flips).

Prior to the workout I consumed nothing other than my usual 40 mL of MCT oil and during the workout I consumed about 4 gm of branched chain amino acids (BCAA) and 10 gm of super starch mixed in my water bottle – so essentially just water.

Immediately prior to the workout, at 6:43 am, my glucose was 77 mg/dL, B-OHB was 3.5 mM*, and lactate was 1.6 mM.

At 7:52 am glucose was 132 mg/dL, B-OHB was 2.2 mM, and lactate was 5.4 mM.

*If you’re wondering why my fasting B-OHB level was so high (recall, I’m usually between 1.0 and 2.0), I suspect it’s at least a partial result of 2 things:

  1. Residual fat breakdown from the previous day’s long ride and caloric deficit, and
  2. On Sunday night I ate (no exaggeration) about half a gallon of my wife’s famous zero sugar, high fat coffee ice cream, which must be the closest thing I’ve ever experienced to heroin in terms of addiction potential.



The figure below summarizes the data from the mini-self-experiment I just described.


Exercise summary data

What can we learn about the interaction between glucose, B-OHB, and lactate?

How does super starch impact my ketosis?

Is ketosis helping me or hurting me?

Stay tuned for next week, when I will try to interpret these results…

Photo by James Thomas on Unsplash

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  • Dave Nelsen

    Looks like Swimming and High Intensity had a similar response with respect to Glucose and Lactate. You’ll probably need to separate your testing days with a day of rest in between so you have a better starting baseline, especially with respect to the B-OHB results. Have you posted the recipe for the high fat ice cream? I don’t like coffee but I’m sure I could add another flavor.

    • Dave, to be super rigorous, I would need to make a few changes, and your idea is a good one, especially if you believe I have not been able to fully replenish whatever hepatic glycogen stores I have.

  • Anthony

    Dr Peter.
    Some light observations.
    1. Seriously, what’s up with your wife? (Christmas gift)
    2. No man understands woman
    3. After swimming for 1 hour 45 minutes and then riding for 104 miles with 5600 feet of elevation, it was rain that stopped your work out?
    Seriously, you are a machine. I would have worked out in the rain and bypassed the bike & swim.
    I will have to wait for the interpretation next week.
    Any chance you can post your wifes famous no sugar ice cream recipie?

    • Anthony, in order:
      1. I *really* thought she would think it was cool and it would ensure we spent good quality time together when working out. I thought she’d want me to test her lactate levels, too.
      2. I think I might agree
      3. If there is any moisture on the tire it is impossible to grip, so you can’t flip it.
      4. Recipe is up in response to a previous question. Enjoy!

      • Kathleen

        “I *really* thought she would think it was cool and it would ensure we spent good quality time together when working out. I thought she’d want me to test her lactate levels, too.”

        . . .Pitiful

        “Noted…But on the good side, whatever you do the next year looks infinitely better, right?”

        Do you seriously believe that?! My my my. . . Until I read that, Dr. Attia, you had fooled me into believing you were an empiricist.

        “No man understands woman”
        “I think I might agree”

        You might be right. (sigh) In lieu of actual understanding (which I cannot provide you with) I offer you a few simple rules of thumb. While not perfect, this is a good place to start…

        1. SILK, simple design, soft color, thin straps. No gift certificates (make the effort) Get a gift receipt (in the likely event that you have no taste).
        2. Whatever gift you ask your father to provide for the TWO of you should serve as a setting for (or compliment to) said clothing article.
        3. Above all: Quality time between husband and wife should NOT involve drawing blood.

        I mean honestly gentlemen. I dare not imagine what your thinking is like when you are not in ketosis.
        Give my best to your beautiful and long suffering wife.

        PS. And tell her that if she brings the almond milk to a brief light simmer, and then cools it in a Bain-marie over ice and water before mixing it with the cream, it will make for fewer ice crystals in the finished product, should she ever have the opportunity to get some of it into the freezer.

        PPS. Fantastic website!

  • I’m interested to hear your interpretation. I’m a little concerned as to how ketosis will affect my endurance activities. I’ve been in ketosis for 9 months now, but I’ve only done two long (which I’m defining as 2+ hours), high intensity endurance workouts in that time. Both have been excruciating and resulted in severe light headedness and nausea and long recovery. After the first one I thought it was due to excessive sweating (it was a very hot day and a grueling hike climbing 3,000 ft in 2.5 miles). even though I drank a lot, I thought maybe I lost too much sodium or something. The 2nd workout last weekend I took some Phinney/Volek advice and had a gram of sodium prior to the workout and tried to drink as much water as I could while riding my bike in 30 mph winds (gotta love Colorado). The extra sodium didn’t seem to have much of an effect, and I was a disaster after I got home.

    For reference, back when I ate carbs, I would routinely do multiple hour, high intensity hikes and bike rides. Other than feeling hungry and sore, I didn’t feel “off” like I do now. Now, I know my sample size is only 2, but I am a little concerned because I have big plans for this summer.

    Also, give me this ice cream recipe immediately.

    • Mike, I’m supplementing an extra 2 gm of sodium every single day, at a minimum. On the days I ride long, I do 2 gm before I ride, and another 2 gm later that day. In other words, I consume 5 to 8 gm of sodium in total every day.

      If readers remember only one thing: WHEN YOU ARE VERY LOW CARB OR KETOTIC, YOU MUST SUPPLEMENT SODIUM EVERY SINGLE DAY, WHETHER YOU FEEL LIKE IT OR NOT. Some days more than others, but for me 2 gm of bouillon is the minimum. If I miss a day, I might feel ok, if I miss 2 days, I’m hosed.

      Second, warm up is everything. I’m I’m going to ride with a group (i.e., ride at the pace of others) I need to EITHER get a few miles in before on my own, or try like crazy to keep up for the first 30 minutes. It just seems to take a bit longer to warm up when you predominantly rely on beta-oxidation.

      Don’t give up on it yet. Recipe is up in response to another question…

      • I would add that people on a ketotic regimen should also remember to eat foods with or supplement with potassium and magnesium as well. All those minerals get excreted and can effect muscle performance.

        • Correct, especially the magnesium — I supplement with 400 mg/day. If your sodium and Mg are in check, potassium is less necessary. I’m currently experimenting with zero supplemental potassium.

        • Fred

          How do you supplement with sodium? These come in pills? I have seen some people put a certain type in water for like long runs, is that what I would drink before a workout or long run?

          • I MUCH prefer bouillon over sodium tablets. Somehow it just works better me on many levels, including bowel regularity. It’s probably worth figuring out what works best individually, though.

        • Helga

          You don’t think it’s possible to get enough from food and generosity with the salt shaker? Do you only need supplementation if you sweat a lot? There have been such mixed benefits/detriments reported as a result of taking vitamins and supplements that it’s always seemed more beneficial just to eat nutritious foods, like fish, nuts, and green veggies, which contain all these minerals.

          • It is, but for me it’s more efficient and “routine” to just know I’m getting my extra 2 gm from the daily dose of bouillon. Intake of sodium (i.e., requirement) does vary by activity and perspiration, of course.

        • Patrick


          To clarify: 2g of sodium, as found in about 4g of salt?

          Or do you and Phinney/Volek mean 2g of sodium chloride?


          • See previous responses. I consume, on average, a serving of bouillon that offers about 2 gm of sodium.

        • Patrick


          My apologies. I was lazy, assuming that salt is about 50% sodium. It’s more like 30%.

          My earlier question draws attention to the distinction between salt and sodium (an ingredient in salt).

          I don’t care to buy bouillon cubes–I make stock and consume it daily. Much tastier!

          I’d like to be sure that I’m consuming the appropriate (minimum) quantity of salt. So I’m eye-balling a carefully weighed 6g of salt, to learn the approximate amount.

          Fellow readers: note “carefully weighed”. Depending on the label you read, 6g of salt is either 6 tsp (some Korean sea salt in my cupboard) or 1 tsp (table salt, according to the food nutrition site you link to). You can get wildly different results from volumetric measures. Pinching, however, can be quite reliable (one of my pinches is about a gram).

          Since Phinney and Volek recommend a range of 2-3g daily, I think this cook’s technique should be fine, especially when combined with the normal human body’s excellent salt-regulation mechanisms (i.e. any excess is easily pissed away, given enough water intake, which a normal sense of thirst will also regulate).



          • Also, keep in mind how much this is more art than science, at least when it comes to dosing. You don’t need a micrometer to measure the length of a car. Agree that homemade bouillon is infinitely better, if you have the time to make it and the room to store it.

      • What do you use as your sodium supplement?

        • Bouillon.

        • Fred

          So when I do a search on bouillon, I believe I can only get it online. Are these the cubes I see? You just pop them in your mouth and chew?

          • NO, doing that would be horrible! You mix it in hot water and drink it look soup. It’s available any grocery store, just try to get one that’s not laced with sugar.

        • Travis Koger

          I actually just nibble on a stock cube rather than mix it with water. 🙂 It is extremely hard to find stock cubes here in the UK without sugar, but the ones I use are very low, 0.6g per cube.

        • Travis Koger

          After posting the comment I tried your method and heated one up in 250ml water. Actually preferred it, so I am converted. The type of cubes I use are called Knorr – The Beef Cube. They also have Lamb, Chicken etc.

      • Anu

        Could you explain a bit more about how you supplement with sodium? Do you just drink bouillon? Is it homemade or from a store? I understand theoretically that I should be eating more sodium when I am ketotic but still a bit puzzled about how to do it, since obviously I can’t be adding more salt than needed to food — and I am already very generous with salt.

        • See previous responses. I use bouillon (plus I’m liberal with salt).

      • Simon PIerre Desrosiers

        If readers remember only one thing: WHEN YOU ARE VERY LOW CARB OR KETOTIC, YOU MUST SUPPLEMENT SODIUM EVERY SINGLE DAY, WHETHER YOU FEEL LIKE IT OR NOT. Some days more than others, but for me 2 gm of bouillon is the minimum. If I miss a day, I might feel ok, if I miss 2 days, I’m hosed.

        I read somewhere on your site that you would do an entry on supplements, but would you mind telling us quickly, or give us a link, on why we should have sodium supplements (I guess eating more salt) when going low carb ? How about Magnesium ?

        While I am at it, may I put gentle pressure to write about ketosis and alcohol sooner than later.

        I love you blog, Thank you for your good work.

        • I have not got to it yet…if you need to know soon, read the book by Phinney and Volek on my books & tools section. Basically, when low carb the kidneys excrete more sodium. Failure to increase sodium intake leads to low sodium (obviously), which has a bunch of problems. See previous comments for more details.

    • Melissa

      My guess in regards to the bouillon helping with your bowel is the wheat. I would encourage you to use something like better than bouillon to make a gluten free broth. Another thought is simply that a warm beverage is known to effect the bowel.
      As a celiac though I have to actively avoid most bouillon due to a base with wheat. Soy sauce and many dressings are the same way. Much like sugar, wheat is everywhere.

  • Teresa

    Forget the interpretation, could we please just get the recipe to your wife’s famous coffee ice cream that is as addictive as heroin?

    OK, I do want the recipe, but I have to say that I have enjoyed your blog very much. You are able to put things in a way that I can understand these technical issues. In other articles I just gloss over them, but on your blog, I actually try to understand. Thanks for communicating with us non-medical people in a way we can actually find out what the science under the covers is all about.

    • Thanks very much, Teresa. I posted the recipe in response to another question. Don’t say I didn’t warn you, though…

  • Dave Nelsen

    One last thing, I can’t imagine the dog house I would be in if I got a blood monitoring device for Christmas as a gift for my wife and I. Don’t make that mistake again.

    • Noted…But on the good side, whatever you do the next year looks infinitely better, right?

      • Dave Nelsen

        This is what I thought of when you described your Christmas gift.

        On the N=1 part of the experiment you might want to get some data replicates to get error bars.

        • Dave, if someone is willing to fund the science, Jeff Volek and I have talked about doing real “studies” on this very topic.

  • Nathan

    I for one would like to hear more about this famous zero sugar ice cream. I’m sincerely hoping that her recipe isn’t a secret!

  • Patrick McDonagh

    To be continued… I can’t take the suspense!

  • Michael W

    Nice post…now I’m just waiting for that coffee ice cream recipe….!

  • Looking forward to the interpretation. Regarding glycosylated hemoglobin, wondering if there’s anything in the idea that there is more turnover in red blood cells in a diabetic compared to a non-diabetic, and the logic may be extended where someone who keeps blood sugar in check, it will last longer, and can therefore accumulate more sugar, and confound HbA1c readings?

    • Bob, certainly possible. I do think, in my particular case, my tiny little crappy RBC’s seem to interfere with the test, though.

    • Liz53

      Chris Kresser stated exactly this on his website:

      The pertinent part is: The main problem is that there is actually a wide variation in how long red blood cells survive in different people. This study, for example, shows that red blood cells live longer than average at normal blood sugars. Researchers found that the lifetime of hemoglobin cells of diabetics turned over in as few as 81 days, while they lived as long as 146 days in non-diabetics.

      I have great blood sugar values and a mysteriously high A1c (5.8). Kresser’s article was very reassuring for me.

  • Maggie

    Thank you so much for the great work you are doing for nutritional science and the low-carb blogosphere, but when are we getting the recipe for your wife’s no-sugar, high-fat coffee ice cream?!

  • Claudia

    “… my wife’s famous zero sugar, high fat coffee ice cream, which must be the closest thing I’ve ever experienced to heroin in terms of addiction potential.”

    You are going to give us the recipe, aren’t you?

  • Fred

    Peter, thanks for the great write up again. However, did I miss what you ate AFTER your workout? Are you stating you ate nothing, just measured?

    • That’s correct. I just measured. About an hour after the swim workout I had bacon and eggs. About an hour after the ride, I had cheese and salami. About half an hour after the lift I had my high fat shake. Measurements were immediately post workout.

      • Fred

        Thanks Peter. So going on with what you responded with last week on a comment of mine…you don’t “replenish” at all with any type of carbs after “hard” workouts? High Fat shake recipe I can find somewhere on your site, right?

        • Right, I don’t have an active plan to replenish glycogen at once. Because I’m so low carb, whenever I consume substrate for gluconeogensis, it’s going there (i.e., to muscle or liver for glycogen replacement). Recipe for my shake is on my “what I eat” post.

  • Doc, can you address this issue if possible: weight loss scenario: a eucaloric 1000 cal/day regimen with an average carb intake of 16/day; if I change up the protein/fat ratios, it effects weight loss. If fat intake gets higher than 45% percent of total calories, weight loss slows down. How does the body choose to burn internal fat over dietary fat, when calories taken in are less than expenditure?

    • It probably varies significantly by person, timing, activity, and type of fat. No doubt there are set points within the body that are under constant adjustment. Some fats (e.g., saturated fats between 6 and 12 carbons, for example, which are very high in coconut and palm), can’t be stored, so they immediately promote their own oxidation. Tough question to really answer without knowing a lot of the details, and even then, it might not be entirely “knowable.”

      • Ah, you may have hit on it. I’ve been eating alot of coconut lately. May have to switch back to butter. Thanks!

      • Michele

        I have read in several comments throughout different posts that “dietary fat is/can be burned before body fat”. This confuses me and I’m trying to figure it out on my own but without a science and medical background, I’m stuck. For me it always seemed like a “no-brainer” to up fat intake and decrease protein intake and, generally, eliminate an insulin response.

        I just got Volek and Phinney’s book. Will I find answers there or have you addressed this somewhere else on the blog???

        I apologize if you have to repeat yourself. I’m just a bit frustrated. Thanks so much.

        • You will definitely find the answers in that book. The sort answer is that it depends on which fats you’re consuming. Some fats we eat can’t actually be stored and must be immediately expended (e.g., via activity, themogenesis, waste).

        • Michele

          Thank you for the short answer and I will continue looking in the book.

          So, the general goal for those wishing to lose weight should thus be to eat the right ratio of fat/protein/carbohydrate until weightloss has occured and then to increase fat intake on which to subsist and remain in ketosis? This is my deduction based on your experience/writing with the specific example that you have increased your MCT oil consumption…

          This deduction of mine will also perhaps be confirmed in the book…

          • Not really. My experiment with increasing MCT consumption is more subtle. Remember, not one “formula” for everyone. Important to really figure out where you’re starting from and what you’re optimizing for.

        • Michele

          Yes, you are right “not one formula for everyone”. I went back and re-read “Revisiting the causality of obesity” as well as “What I Actually Eat” to, so-to-speak, re-focus on the point behind all this info (info from your posts, people’s valuable comments, et cetera).

          Because this issue is so complex I guess I was trying to come up with the perfect elevator speech for when I talk to people who are interested…kind of like your cool four-corner with goals vs. genetics. I was even thinking of putting together a PowerPoint presentation for my family (am in consulting too).

          Anyway, I’ll keep at it. Thanks for faithfully answering again and I promise not to ask either about the ice cream recipe nor the boullion…

    • Michele

      Hi Peter,

      I have that presentation I mentioned (Post March 9). Where do I send it if you would like a look at it?

      Please keep in mind…I’m just an amateur here trying to open the eyes of my aging diabetic father…

    • Alexandra M

      I’d certainly be interested in that elevator speech! I just finished writing a reply to the article in my local paper (the one that recommended margarine and more grains) and it was a struggle to keep it from going all over the place…

    • Michele

      …I have mailed the presentation (9 slides including title page, so not really an elevator speech) to Peter.

      If Peter mentions that it adds value and sends the correct message, then I would be willing to share it.

    • Michele

      I placed the presentation on a file-sharing system. I hope this works for everyone.

    • Dan

      Michele, I enjoyed your presentation. Thank you for sharing it.

    • Michele

      Thanks very much. I would like to tackle the effect of carb intolerance on cholesterol next. When I have it, I’ll post a link like I did here. Maybe eventually we can come up with a type of “Carbs for Dummies” (in the sense of the “Dummies” book-series I mean).

      • I’m working on it, but it’s really tough to write about this topic in an accurate, yet understandable way.

    • Michele

      Peter, I probably would not come up with as scientific and explanation as you but if there is any way I can help/contribute and save you some time then give me a shout or point me to the info I need to summarize…

  • Greg

    my wife’s famous zero sugar, high fat coffee ice cream

    Is that something you’re willing to share? The recipe, I mean.

    • Greg, I’m not sure it’s ethical, or even LEGAL, to share something with such addictive potential…
      We’re still working on the nuances, but the current version is composed of 3.5 cups whole fat (35% fat) cream, 1 cup of zero sugar almond milk, 1 tbsp vanilla extract, 2 tbsp almond extract, 3 tbsp ground espresso powder, and 2 tbsp xylitol. This makes enough to feed about 8 normal people, or me in one sitting.
      You’ll need an ice cream maker, obviously, to mix at at freezing temperatures.

      • Dan Simonelli

        Ehhh, ethics schmethics…given the people what they want! And I want coffee ice cream, my favorite, which I’ve only indulged in a couple times since embarking on my low-carb adventure…so I’m so excited about making some!

      • I too had already copied the text

        “my wife’s famous zero sugar, high fat coffee ice cream, which must be the closest thing I’ve ever experienced to heroin in terms of addiction potential” to paste and ask about but as I suspected, someone beat me to it! Thanks for sharing the recipe – sounds amazing!

      • Richard

        Hi Peter,

        What kind of cream are you using? I was using generic heavy cream, or heavy whipping cream. I have since discovered that those typically have thickeners and other additives. So I switched to the stuff that Peet’s Coffee (up here in the Bay Area) uses: Berkeley Farms “Manufacturing Cream”. It has 40% fat content and is pure cream, nothing else. It is usually available only for restaurants / food service, so I have been buying it at Smart & Final.

        • I use a brand from Costo (only place I can afford it! — $6 for a gallon versus $4 for pint at Whole Foods). I do like the brand you mention. I just make sure I’m consuming a variant that does not add dextrose, as some do. As you note, pure is better.

      • Teresa

        I’m wondering what “ground espresso powder is.” Is that the espresso powder that you can reconstitute with water, like instant coffee, or is it actual beans that have been ground into a powder? If it’s the first, do you measure before grinding?

        Have you thought about adding some vegetable gums like guar gum and xanthan gum to the ice cream? They improve the mouth feel, but be careful about using too much. I prefer xanthan gum, though some people claim that a combination of the two works best. They can be hard to add without clumping, but if you can pour them into the vortex of something in the blender or at least add them to something high in fat like the cream rather than the almond milk, they seem to work fine. They are 100% fiber, I believe, and should not affect blood sugar in any negative way. They give a nice silky texture to things like ice cream.

        • I think you could use either, but we use the stuff one can mix with water for sub-stellar espresso. For me, personally, the “feel” and texture are perfect now, but I think your ideas would great for folks who want a different feel.

    • Matt Taylor

      That’s funny – this was the first question that came to my mind. Looking forward to next week’s analysis too though.

      • Edmund Brown

        I wondered about this too. I really wonder about the texture of it once it’s been in the freezer for a day or two. My experience with home made ice creams led me to believe that the sugar played an important role in the “mouth feel” of the frozen delight (these days I just don’t eat ice cream). But it was much less of an issue straight out of the maker. Perhaps this stuff is so good it doesn’t even get into the freezer for storage?

        • Guys, I have no data to offer on this point. Storage is not an issue.

      • Lacie

        Yeah, I read all the nerd stuff and love it, but the takeaway is still the ice cream recipe.

        • Lacie (and everyone else), you’re killing me!!!! I work so hard on the science and all you want are the recipes… 🙂

    • Matt Taylor

      I made some of the Attia family’s coffee ice cream recipe last weekend. Everybody loved it. I think I like stronger coffee taste and have more of a sweet tooth than Peter, so I ended up with a little more espresso power, xylitol, and a little bit of stevia too. While I was making a mess, I came up with a chocolate recipe myself that is just as easy. A little espresso powder added to the cocoa powder really brings out a darker chocolate flavor. The two gallons I made (1 coffee and 1 chocolate) did not last 36 hours at my house. Anyway… thanks as always for all your efforts.

      • Matt, that sounds awesome. I may try it right now. Literally.

  • David

    Have you recently increased your MCT dosage? In your “What I actually eat” post you mention 30mL of MCT but looks like you are now at 40mL.

    • Good catch, David! Yes, upped it about a month ago. Just tweaking…

  • Gretchen

    Peter, in a blog I did on A1c ( I mentioned thalassemia.

    “People with unusual hemoglobin types, for example those with sickle cell anemia or thalassemia, or those who keep producing fetal hemoglobin even as adults, may have A1c results that don’t jibe with their meter readings. This is because these less common hemoglobin variants, as well as other rarer variants, although they work to transport oxygen in the blood, produce slightly different varieties of glycated hemoglobin that react differently in the A1c tests.”

    It shouldn’t affect regular blood glucose testing. The A1c test separates out hemoglobins according to their charge or immunologic properties, and the glycated unusual hemoglobins don’t run with the A1c fraction.

    • Yes, it may be completely unrelated. The most compelling reason for why I think the meter runs a bit high is that I’ve tested it side-by-side 4 times. Delta’s seem to be fine, and fortunately, the other measurements seem spot on.

  • Peter,

    I have really been enjoying your posts. I, too, do a lot of n=1 experiments. In terms of your glycomark testing, dietary restriction can effect levels as well. Myself as well as several of my low carb/hi fat dieting patients all have low glycomark tests (10-12). It puzzled me initially and i went as fair as wearing a CGMS for a week and it did not correlate with my glycomark of 11.7. Fat has lower levels of 1,5-AG, so that could also be a reason your glycomark was low. I have not been able to find (nor do the makers of glycomark) have any data on thresholds of intake.

    I also find it interesting in a lot my low carb patients that HbA1C hangs around 5.4-5.5. The only thing i can attribute to could be increases in BG after HIIT type activities (ie crossfit) depending on frequency during the week as not in some of your excursions post exercise

    • Isn’t it so much fun doing this stuff? Learning so much about the most remarkable machine on earth — no two exactly alike.

    • Same here. I’ve been training and racing at the elite level on a mountain bike in ketosis for two years now. My A1c is 5.2, fasting glucose 90, insulin 2.1, c-peptide 1.0, MCV 94. GlycoMark 6.0. There’s a chance my BG gets up to 180 during the cyclocross races I compete in at the moment but it seems a bit of stretch.

  • Hi Peter,

    Keep up your postings–I really enjoy the data… P.S., I was a USA swimmer–100/200M Breaststroke + 200IM. If I only knew back then what I know now…

    All my Best,

    Stella Metsovas B.S., CCN

    • Stella, that’s awesome. I bet you can still kick my butt up and down the pool. I’m actually a breaststroker, too.

  • Intriguing results. Thank you for sharing them. It is very helpful to have a rough/nominal/about number for carbohydrates per day to help generate ketones. Since the brain can operate on ketones, I’m thinking that vigorous swimming exercise may be especially helpful to those with dementia who are also physically fit.

    • There is almost daily increasing amount of data suggesting that ketones are particularly brain-healthy can play a huge role in preventing and reversing dementia. I do plan to get to this in time…so much to write about.

      • Mike

        I’m very interested in this topic. My mother has Alzheimer’s, her brother and father died from it, as well as *all* of her father’s siblings. I feel so targeted I can feel the laser dot on my forehead.

        I first saw mention of the connection in Taube’s GCBC, and then here:
        which I interpret as an attempt to boost the brain’s glucose metabolism in insulin-insensitive brains.

        Now I’m reading more and more about using ketosis instead: and

        There are sketchy web sites out there promoting coconut oil and such, but they reek of homeopathy and snake oil. I’d like to find out who is doing the research and who can I trust.

        • Mike, I appreciate your concern. Perhaps to a lesser degree I feel that way about heart disease. Presumably you’ve been tested for ApoE genotyping?
          I do plan to write about this, though I don’t know I’ll have all of the answers. Quick response: I have a lot of reasons to believe that ketosis can be protective, at least delay onset.

    • Mike

      I haven’t done genetic testing yet. It seems like they are finding more and more markers, and I’m hoping the price will come down and these commercial tests will include these new markers. Besides, even people with two APOE ?4 alleles don’t always get Alzheimer’s.

      All I can do for the time being (whether I know if I have the APOE ?4 alleles or not) is eat low-carb, but it would be nice to know if I just need to eat low-carb and keep my insulin levels low and prevent my brain (and body) from becoming insulin insensitive, or if I need to be all the way into ketosis to get protective benefit (if any exists). I’m 53 and the difference between just a low carb lifestyle or trying to stay in ketosis for 30 years requires a big difference in motivation for me.

  • Bev

    Hello Peter
    I enjoy your humour. Our lactate meter was a carpenters’ dust collection system for DH’s shop. Not for me…but really, in the big scheme of things, as official house duster, I suspect it was.
    A quick note to thank you for sharing this work. I am new to all this (picked up Protein Power Feb 2) 54 yr female recreational runner, yoga & TRX practioner, who banged on 15 pounds in about 8 months and said WHAT the heck is going on? I wish I had a buck for every person who told me I was ‘building muscle’ with the TRX. What I was building was a big fat gut. My doc said ‘menopause’ and recommended watching the carbs & getting enough protein. My adult son who was diagnosed 2 years ago with type 1 (at age 25 – likely an autoimmune attack) has been telling me for a year now he doesn’t count fat…just carbs. And he doesn’t use low fat anything. I finally ‘heard’ him. What an education I am getting! I am even playing with ketostix and often light up those shades of violet! Very interesting stuff.
    At risk of this quick note turning into a speech, I will attempt to finish by saying I feel more energetic than I have in probably 3 years, and it’s only been 5 weeks! Lost my top end run speed, but as a recreational runner….it doesn’t exactly take me off the podium anyway. ? I suffered with the menopause sleep interruption that so many women do. I now sleep and if I do wake up, I can now go right back to sleep. Besides the 11 pounds I have lost, the proper sleep is a huge gift. And my brain is getting a good workout too in reading your posts, and others; trying to wrap my head around the science. On low fat, I was always looking for the next thing to eat. Now I’m feeling a bit devilish making blue cheese dip for my salt n’ pepper wings. Who knew?
    To close, I am keeping as detailed a log as the layman can…food consumption, blood pressure, bodily ‘functions’, exercise, sleep etc., and hoping when I return to my doctor at April end, she is willing to play along. I am due to have my ‘numbers’ checked anyways, so excited for that result.
    It’s pretty funny to experience a cravings switch from bread/popcorn for say….a bowl of strawberries (with fresh cream, of course) I really could go on and on….I cannot believe how great I feel!

    • Bev, amazing story. Thanks for sharing. Keep up your incredible journey and let your son know to check out the blog, A Sweet Life.

  • Although a lot of your science was over my head,
    I enjoyed the read and especially the personal antidotes. It was interesting seeing the differences in the graphs due to the difference in activity. I really didn’t expect there to be so much difference. Looking forward to reading part two!

  • Patricia

    Can you suggest a resource for finding a doctor who is on board with these concepts (Los Angeles area)?

    • Check Jimmy Moore’s website. He has a list of low carb docs around the country.

    • Robert I

      Hi Peter,

      I noticed this list contains a lot of Chiros and Naturos who call themselves doctors. That perhaps unintended endorsement from you seems to conflict with everything I’ve observed about you and Gary Taubes. You have both demonstrated a highly ethical and critical approach to science and in so doing, I think, advanced the cause of a critical approach to human nutrition.
      If the above two categories of “doctors,” bring any science to the table can you explain?
      Robert I

      • I’m not advocating for anyone I don’t know. I’m pointing out a resource to consider. But to your point, why does having an MD or a PhD matter? Am I only credible because I do? Is Dean Ornish “right” because he has and MD? Is Gary not credible because he has neither an MD nor a PhD? Same question for Mark Sisson, Robb Wolf, and many others?
        Don’t judge a person by their degrees or lack of degrees. Judge them by what they know and what practice.

    • I’d love to know which doctor Mark Sisson goes to- he lives in Malibu. Wonder if he’d share that info- guessing Peter doesn’t have that insider info? I was surprised when checking Jimmy’s site, how few docs there were. I’m thinking of going to the cute guy in Woodland hills 😉

  • Hits

    you are an absolutely amazing.
    Its great reading your blog and love your spirit.

  • Scott B

    Peter – forget all the data questions (ketosis, lactate, blah, blah, blah). The bigger question is – how do you get enough money in the wife bank to ride a century on any given Sunday? 😉 Seriously though, how do you find so much time to exercise? Will you give us a week in your exercise life?

    Also – thanks for the recommendation on Superstarch. I felt incredibly strong on the bike this weekend with Generation UCAN on board. Also, Xylitol is sweet! Bought a five pound bag and can’t tell the difference between it and sugar. 🙂

    • Scott, you’ve stumbled on my secret in life (and this goes for all you single guys out there!) — marry a women with low expectations! I was so luck to marry my absolutely wonderful wife (if there were a Wife Olympics, she’d be the equivalent of Michael Phelps) while working 114 hours per week in residency. She expected little more than a pulse. I’m actually so lucky that she not only tolerates my antics, but supports them, despite her own amazing antics (my wife is 10 times the athlete I am and still manages her own training schedule, job, etc). Back when I was mostly training for marathon swimming, she would actually kayak for 8 hours for me on training swims!

      • Scott B

        Lol. If you tell me you’re having sex twice a day I’ll slit my wrists now . . .

  • Roy Harju

    Very interesting, informative and entertaining stuff, Peter. Thanks for sharing. I was struggling with what to fuel with on long workouts, and you’ve given me some great ideas to try. I’ll give the super starch a try. I was just looking over their website and something struck me. In the comparison of super starch to regular starch to maltodextrin, one can see how super starch is superior to maltodextrin, in terms of muting a glycemic spike, but what also stood out for me was that it was only marginally better (13%) than regular old corn starch. I see uncooked corn starch has a molecular weight of about 250,000 and super starch of 500,000 – 700,000. So I guess that raises the question: would using regular uncooked corn starch as an energy drink also be better than using a maltodextrin based energy drink?

    • It’s a great point. If you read the history of treating of kids with glycogen storage disease (GSD — the disease for which super starch was actually developed), you’ll note that prior to super starch the “gold standard” for treating GSD was actually using argo starch. So yes, I think argo starch would be better than maltodextrin.

  • RobbyG

    You might want to edit the blog post and put the recipe in bold, large font, and a different color! I will be trying it out this weekend or next.

  • Mark

    Great article again and looking up to the follow up article. I’ve been doing crossfit for over a year now. At my gym, we mostly do high intensity barbell lifting, heavy barbell lifting and some sprinting. I had never had a problem with stamina on the high carb diet. Once I was in shape and I was usually one of the first people done with the workouts. About 3 months ago I decided to try the low carb diet to lose weight and improve my health. I’ve been consistently under 50gm carbs for the 3 months with around 5 days that I went over that amount. On the low carb diet, I usually get tired easily when working out and now I am usually the last person done with the timed workouts. I drink a whey protein drink (mixed in water) and take fish oil. I just bought the super starch today to give it a try. Another thing, which is probably tied to being tired, I’m not as driven to go workout as I used to be. Conversely, I have lost about 15lbs and my cholesterol and blood pressure have dropped since eating this way. Any suggestions on how to not be so tired when working out? On an unrestricted carb diet I was never tired like I am now. Thanks, Mark

    • Hmmm, could be a number of factors, including just adaptation. It took me MONTHS to adjust to ketosis. I wonder what would happen if you tried some experiments? MCT supplements, CLA? Creatine? Tough to troubleshoot over blog.

  • Tim

    Hey Peter –
    Curious if there is any particular reason you consume the cheese or nuts on your long rides. Personal preference? Hunger? Technically you wouldn’t be “bonking”, correct? In theory you have an “unlimited” amount of stored energy? I guess what I’m getting at is, nutritional normal ketosis ranges from about point something mm to about 5mm –correct. An unhealthy level would occur at around anything above 15mm or so? -based on Phinney and Voker.?As you go longer, all things equal, with no food, etc, wouldn’t the ketone level rise? So given the longer duration of the ride are you just ensuring that you staying at a safe level? Or is that not what happens (ketones rising during activity)? Best bet to consume something during a long distance event?
    Curious as I do endurance events, recently completed ½ marathon and a full marathon. Times weren’t special, the only thing consumed before the event was a lot of chicken broth –maybe 4000 mg sodium. Wanted to consume bcaa during, but forgot bottle, ended up after the event. During the run, I was feeling pretty good. Unfortunately, I didn’t test my ketone levels afterward.
    Doesn’t seem to be a ton of research out there on endurance events and ketosis – so I can appreciate your self experimentation.

    • Great question, Tim. You’re technically correct. I don’t need to eat to prevent bonking, unless you believe I need a tiny bit of oxaloacetate to run the Crebs Cycle (this is a debatable point, though I don’t think so). Maybe it’s just “habit.” I do think the tiny amounts of protein (from the nuts) probably help with delaying muscle breakdown. As far as keeping B-OHB below, say, 15, my pancreas actually takes care of it. As B-OHB levels rise, insulin gets secreted and this sort of acts in a feedback loop to keep ’em in check.

  • Dave C


    Thank you so much for taking the time to do this testing. I found it fascinating. I think one of the most surprising results was that you did 100 miles with that kind of climbing and only consumed 120/calories an hour and never bonked. Definitely encouraging as it seems to prove that your body is able to make glucose from fat.

    I had a question … I have been borderline hypertensive before unsurprisingly (140/88) and have real concerns about adding that much salt even though I’m now below 20g of carbs a day. I’m going to see my doctor tomorrow because my BP has been high for three days around 150/90 (I just finished my first week in ketosis today). I’m normally taking in 1500mg of sodium a day.

    I’m just not sure what to do. I don’t want to intake bunch of sodium and have that lead to worse hypertension. I’m drinking 3-4 liters of water a day as well.

    I just don’t know what to tell my doctor tomorrow.

    Thanks for the great website!

    • One quick correction…my body doesn’t technically make glucose out of fat, it makes ketones, which my brain actually prefers to glucose, hence the reason I don’t bonk. There are lots of reasons for hypertension, so make sure you doctor is looking for them (well beyond what is called “essential hypertension”). In your case, I’d be curious to see what would happen to your BP if you did not, at least temporarily, supplement with sodium.

      • Dave C

        So my BP when I arrived at 9:30 was 177/90 and had a “slightly” irregular HB according to the EKG they did. By the end of the visit I was back to 140/90.

        They did bloodwork to check for sodium, potassium, etc too … I’ll be interested to see where the results end up.

        Thanks for responding. I’m hoping the bloodwork gives me targets for the magnesium/potassium/sodium levels I need to supplement so I don’t exacerbate my HBP.

  • Steve El

    Of late, in the paleo/primal blogosphere (particularly “Free the Animal”) there’s been a lot of stuff about food reward/palatability/satiety as the cause(s) of the obesity/type II diabetes epidemics as opposed to over consumption of carbs. I’m a low carber, 40 pounds gone so far, but I guess this planted a seed of doubt. I just discovered your terrific blog, through Dr. Eades, and feel reenergized. I’d love to get your take on this. Thank you, Sir.

    • I think there may be something to this idea, for sure, but there are lots of things this idea does NOT explain. Hence, I would think of this not as the “first-order” term. These are testable hypotheses, though, so I hope the scientific community can start to agree on testing versus just arguing and re-stating.

  • David

    Hi Peter,

    I’m just beginning a ketosis diet for the past week. I’ve been thinking about this very question, how do I perform endurance exercise with few carbs? Timely post!

    You mention you use Generation UCAN on your rides. Do you use the variety that includes protein or the one without? Do I need protein on my rides or will it interfere to utilize fat for energy? Thanks for your help.


    • I use the super starch only, not the chocolate or vanilla flavors with protein, but that’s just because I don’t like sweet things when I’m exercising, so I mostly consume the flavorless super starch.

  • Garth

    Hi Peter,

    What’s your wife’s ice cream recipe? (Just kidding! But I will try that this summer. It looks pretty darn good.)

    For reference, do you have any idea what your average glucose levels were prior to carb reduction? You say your mean has been 90 or so for the past year, with noted caveats about potential issues with the readings. Did you get any sort baseline prior to shifting your diet?

    I’m interested to read your analysis next week.

    • See previous responses for recipe. Mean fasting glucose before carb restriction was about 15 higher. A1C probably 1.5 to 2.0 higher, but hard to be sure because of beta-thal.

  • Dorian

    Your wife’s famous zero sugar, high fat coffee ice cream: any chance of providing the recipe? Sounds delicious!

    • Already done. Check previous comment on this post.

  • Chris

    Slightly off-topic, but I thought you’d appreciate this…very satisfying:

    I wonder how long it will take for the conventional wisdom to topple. Things seem to really be picking up speed since GCBC/WWGF, and I think your website is contributing a huge amount as well. Excellent work.

    • I’ve read some great stuff from Dr. Lundell. It will “only” take about 20% of docs getting to this point before we can start to appreciate a real tipping point. Thanks for sharing.

  • Paul

    If you talk about 2 gr of additional sodium do you mean 2 gr of salt or 2 gr of sodium (which is higher since salt is only 40% or so sodium).


    • I take 2 to 4 gm of supplemental sodium (which is roughly 5 to 10 gm of bouillon).

      • Edmund Brown

        I’ve been fairly low carb eating for several years now (since reading Taubes’ Good Calories, Bad Calories), but not rigorous by any means. The last few weeks I’ve cut a few more carbs and gone to a high fat chocolate coconut milk smoothy for breakfast (I start looking forward to it before I fall asleep) and on some days I get mildly nauseated by lunch time. Today I tried a urine ketone test and was positive when I felt queasy. I drank some salt water and felt better within an hour. I ate a fatty lunch to continue the experiment and stayed ketotic until dinner and felt fine.

        I just ordered Phinney and Volek’s book since I’ve seen you recommend it to others when they ask about going ketotic, and how to manage it.

        At this time I don’t have any grand design to go into full blown nutritional ketosis, but it has me thinking… are there any potential metabolic problems with “living on the edge” so to speak? I have yet to read/experience any generally dietary regime that I find half so compelling as the primal/paleo/low carb thing, and I can easily rationalize a “back in the day” scenario where our ancestors slipped into and out of varying levels of ketosis daily, weekly, or monthly depending on the season and what type of food was available. But I also recognize that this is mostly my personal bias speaking and not based on much direct evidence.

        • It requires a bit more thinking to eat like this, mainly because the food infrastructure around us doesn’t support it, but it’s no different that learning a new skill. At first it requires great conscious effort, but over time it becomes more autonomic.

  • Outstanding once again Peter.

  • Pingback: More links! « Neanderthal, Dark & Handsome()

  • Another great post Peter. Keep it up!

  • Maryann

    Hi Peter,

    I have to say…this particular blog is hilarious 🙂 You have the patience of a saint, lol! Between repeated bullion questions and increasingly militant demands for the secret ice cream recipe, you have had your patience tried…and we’re not even family! This is a lesson to us all to read the blog from the begining before asking something 🙂 Thank you for all of your patience and for taking so much of your time to teach us… you’re super!

    God bless,maryann

    • Thank you! I hope folks can keep this in mind…

  • Maryann

    Mrs. Attia is the woman who started it all when she encouraged you to be “a little less not thin”. You have a great wife, and she’s talented just like you, too!

  • Edmund Brown

    From the number of requests for the recipe it looks like your wife’s sugar free ice cream deserves a post of its own!

  • Dan Hackam

    Interesting thing about salt. I bonked something bad in the first month of low carb diet because I was not consuming sufficient salt (and probably fluid). I couldn’t stand the taste of bouillon. The only thing that eventually helped the dizziness, headaches and fatigue was a half teaspoon of salt put on the back of my tongue and washed down with a huge glass of water. I am still extremely carb-restricted (<20 g per day, if even that), but no longer need any salt whatsoever. The ketoadaptation process probably takes at least 8 weeks. Get through this hump and it is relatively easy sailing. 33 lbs later….

    (PS, I do not exercise. If you exercise, you need to replete your electrolytes and fluid loss – no question)

  • Excellent self-experiment! That’s really great and exactly what I love to read. Investigating to accurately understand how the body works on a physiological level, and then adapting what we do and eat to optimise health. The results make perfect sense: the higher the intensity, the more stimulation to the adrenals that secrete both growth hormone and stress hormones. The stress hormones suppress lipolysis and stimulate the liver to churn out glucose. Since glucose becomes the primary cellular fuel, lactate concentrations rise. There is a close relationship between the intensity and duration. The swimming intervals are still relatively long, whereas the “dry-land” high-intensity work is really short, and thus that much more intense. Really great stuff! I can’t wait to read the continuation.

    I just wrote up the results of my own self-experiment on the effect of dietary cholesterol on its concentration in the blood. I have to say that I kind of knew the answer already from reading it in books, but I wanted to see for myself. Here is it:

  • Jordan Jones

    The correlating increase in glucose and lactate and the decrease in B-OHB is not surprising to me in HIT. It would be interesting to know your level’s B-OHB 1, 2, 3, etc. hours post workout while your glycogen stores where empty.

    I have never tested it, but my breath (according to my wife) does seem to be a bit more ketotic 1 and 2 hours after a Tabata bout.

  • DB

    Peter, I have just recently discovered your blog. I find it really interesting. I have just started low carb two weeks ago and I’m training for a half ironman in August. I am also a Type 1 diabetic. My question is in regard to workout and race fueling. Is this your typical fuel for a 6 hour endurance workout? Would I have to be in ketosis to follow such a plan or would you suggest starting now to allow my body to adapt?

    • Yes, this is typical for me. If I was non-ketotic low-carb, I would likely be less dependent on fat, but still more metabolically flexible than a “normal” person. Because of your T1D, it’s going to be a bit more work, but still very doable. You must check out the site A Sweet Life and contact Mike Aviad ( Mike is T1D and a marathoner. He’s also very low carb.

  • Helga

    I have 2 general questions about the relationship between insulin/ketosis/weight loss.

    1.) Is it possible to be in ketosis and not lose extra weight?

    It seems most of the theories behind low carb diets failing to produce weight loss have to do with insulin response being caused by other stimulus (cephalic response), or hidden carbs.

    2.) If this were the case, would the insulin response take a person out of ketosis, or decrease ketone levels?

    Unsurprisingly, this question has a personal motivation. Since I’ve begun carb restriction I’ve felt better- more energy, no more low blood sugar issues. However, I haven’t lost any really noticeable weight. I’m not actually overweight, but I know I have a bit more flesh than I did in my 20’s, so I’m sure I have some to spare. I’ve measured my ketones and they are always between 40-100 mg/dl per keto-sticks. I always appreciate your feedback. Thank you for taking the time to answer my/other readers questions.

    • 1. Yes you can be in ketosis and plateau in weight (like I have been for many months).

      2. For many people, being in ketosis is a “leaner” state than not being in ketosis, but not necessarily for everyone.

      It can take a while for your body to begin to mobilize our fat stores. But you said the most important thing yourself…you FEEL better. Body composition is but one part of it.

    • Helga

      Do you know a good resource for understanding the basic biochemistry of the body in ketosis? I guess I was really wondering, if there is insulin over-secretion for someone in ketosis, what happens? Does it decrease ketone levels? Scavenge blood sugar? People in ketosis still have ambient levels of blood glucose, where does it come from? Is it continually being used then replenished from gluconeogenesis, or simply recirculating and conserved? I’m afraid a biochemistry textbook is too basic, but I’m also not sure I want subscribe to a bunch of journals to get overly specific concepts explained. Or… is there even such a resource? Has the research been done?

      • The book by Phinney and Volek in my books & tools section.

    • Garry

      If you think of nutritional ketosis as helping you lose excess body fat, I think it may help you understand the process better. I’ve been in ketosis for several months but haven’t lost any additional weight. I’m leaner than I’ve ever been. I think after a while, you reach a point of equilibrium because your substrate level (fat) is so low.

  • Bobby

    Peter:I have been on a low carb diet modeled after your diet for the last few months and decided to have a blood test taken to assess the diet. I was shocked to see my glucose was 105 when it generally has been in the low to mid 90’s. Any idea what I’m doing wrong?
    Most of my blood lipid were up. My VAP test showed my LDL at 145, my total cholesterol was 249, Lp(a) 0f 15, and a positive HDL 0f 92.
    My triglycerides were normal at 48.
    What do you think I’m doing wrong? I feel great but these results confuse me. Should the increase in blood lipids concern me? I am a 64 year old runner who is not overweight.
    I’m just looking for your opinion and and feedback. Any suggestions will be helpful. Many thanks!

    • Bobby, I can’t comment on personal medical questions on a blog. But I can tell you that a VAP is of very little value. There numbers actually tell me very little about your risk. You need an NMR to count LDL particles and HDL particles. The only thing I can see from this is that your TG to HDL-C is very favorable, but no idea what your risk is without know LDL-P and HDL-P. I’ll do some serious writing about this in the (near, I hope) future.

  • Bobby

    Peter: I understand that you can’t comment on my personal medical questions. As a general question, not specifically about me, why would an individual on a low carb diet see an increase in blood glucose?

    • This would be unusual, but there are countless factors that could contribute to it (previous meals, degree of fasting, accuracy of measurement, etc.).

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  • Anu

    Any comments about the latest LA Times article that’s floating around about any amount of red meat increasing your risk of dying earlier:,0,565423.story I know that correlation is not causation, but have you by any chance looked at this study specifically (or know someone who has?).

    • I’ll address in the detail in next week’s post. Quick answer on my FB page.

    • KevinF

      I love that the claim is that eating red meat is associated with higher death rates from ALL CAUSES. This study tells us that beef-eaters are more likely to get hit by falling pianos!

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  • Thanks for you great self experimentation.
    I am on a similar journey.
    I believe that part of what you saw for your high morning B-OH after your Day 2 workout may have been attributed to the UCAN SuperStarch. If you look at the data from their OK study you will see that they only followed fat oxidation for 90 minutes during the recovery phase,however, not only was it significantly higher than using maltodextrin for recovery it was also separating in magnitude indicating the potential for more fat oxidation (fuel) utility during recovery and continuing long after. What do you think?

    Will you retry this study with a change in the testing order? Start with the high intensity and move to the bike or start with the bike and finish with the swim? I know there are several permutations but you may find the answer to the swim influence on the B-OH or perhaps you should use UCAN for each workout.

    Keep playing.

    • Thanks, Sheri. It’s possible, for sure. The experiment I’d like to do next is ingest the same amount of super starch while sitting at the computer and see how it impacts ketosis.

  • Blue

    I have searched through 3 pages, 148 comments, for the coffee ice cream recipe.

    I cannot find the ice cream recipe.

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  • Anne

    Heh-heh; and here I thought the entire point of Life in Ketosis to begin with is precisely so I could STOP doing painful, boring, senseless forced exercise. What was I thinking? 😉

  • Ben D

    What device do you use to measure your B-OHB concentration?

    • See link in this post.

    • Ben D

      Are you paying $5/each for ketone strips?

      • No, I pay less, typically, but they aren’t cheap. Good thing I don’t spend money on cigarettes 🙂

  • Hello Pete,

    Outstanding Blog! Thank You! I was debating a nutritionist with extreme high credentials. When I told her I was in ketosis she never fell over! She told me I was damaging my brain and body. I can’t tell you my frustration, because nutritionist tend to fall back on the statement that “ketosis is bad for you body and brain”. How would you response to someone that is convinced ketosis is dangerous?

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  • Mark

    Hey, Peter.

    I’ve been training in ketosis for a couple of months now. Just in the last couple of weeks, based on your advice, I’ve upped my fat and lowered my protein from 160 to a little over 100 grams. It’s accelerated my weight loss.

    One problem I’ve had in the past on carb restriction in working out at the gym or running, was becoming light headed and feeling like I might faint. I assumed it was only attributable to low glycogen stores. I’ve added three grams of sodium daily, and there is a world of difference in both my endurance and how I feel. Normally after a long run, I feel like hammered shit, but I felt good this week even after a three-hour run. It’s also the first time I’ve run past two hours without consuming any carbs during the run, and I felt great. It’s really a stunning difference.

    One book I saw mentioned here in the comments was Phinney’s and Volek’s “The Art and Science of Low Carb Performance.” I bought it, and it covers everything. You should put that in your “Books and Tools” section.

    Also, your ice cream recipe is better with coconut milk. The kind in the dairy section next to the almond milk, not the canned stuff. The fat gives it a creamery consistency. My wife, kid and I preferred it to the almond milk version. Plus, you get the added benefit of MCTs mixed in. Give it a shot!

    • Mark, I’ve got their book, but I haven’t read it yet. Will get it up there when I do so. Look forward to trying the coconut milk idea. Are you substituting it in for the cream or the almond milk?

  • Mark

    I substituted for the almond milk. I liked it with both, but I think the coconut milk version came out better. Here in Atlantic Canada, we have two brands: Silk and So Delicious. The So delicious brand doesn’t have a strong coconut flavor. I’m not sure if these brands are available across the whole U.S.

  • Chris

    Hi Peter, first off great blog, this is exactly what I was looking for. I’m a low-carb endurance athlete (aspiring triathlete) and I’ve been looking for others out there who are training at a high level on a ketogenic diet. I’ve recently decided to give strict ketogenic a try. (before I had been floating around 50-100g carbs per day, with larger amounts after intense or really long workouts).

    I was very intrigued after hearing about Superstarch and its negligible insulin response. It seems like as you’ve said, this could be the key to allowing higher intensity glycolytic efforts while remaining ketogenic. I was wondering if you use superstarch at any time other than during your very long bike workouts to replenish glycogen? For example, do you ever take in any after a very intense lifting session or swim in the 1-2 hour range?

    I know you are planning on writing a dedicated post on Superstarch, so if you’d rather wait util then to address these kinds of questions then I understand. I’m looking forward to that post.

    Thanks for all the great information!


    • I’ll definitely write about this in the future, but you should definitely experiment with it around various types of workouts (type, intensity, duration).

  • I love your blog and all the information, but I do translate some of it into “better nutritional forms” as I read it. For instance, here’s a recipe for homemade bouillon that has to be nutritionally superior to commercial varieties. Think source of your food half as conscientiously as you measure your electrolytes — you eat good meat, right?

    And then the coconut milk varieties in the refrigerated section — you have to read their list of ingredients as well. Too processed, and I’m planning on making your ice cream recipe (when I have a party and it won’t be sitting around), I wonder if the real – canned – coconut milk can be modified somehow.. I’ll let you know if it’s any good.

    Think food quality!

    • Oh yes, homemade bouillon is much better. It’s a trade-off.

  • Michael

    What is the metabolic necessity for carbohydrates? Why must one eat a minimum of say 30g of carb per day? There must be some process that simply cannot be entirely fueled by ketosis in order for there to be a minimum required. My supposition is that a person who has 50 pounds of excess fat could not live for 100 days with no carbs at all.

  • Michael

    i am a type one insulin dependent diabetic of 52 year duration…. if my blood sugar level drops low enough i would bet that i would pass out no matter how strongly into ketosis i had gone… i do not believe beta hydroxybutyrate in very high availability could prevent this, am i wrong???

    • If B-OHB levels are high enough (3-5 mM), one can tolerate BG levels below 30 mg/dL, but as a T1D, it’s a very delicate balance and not worth playing with.

  • Michael

    I am pretty tolerant of low BS. At 50 I feel no change at all. While bicycling, for instance, I will only discover that it is 50 due to routine test before an insulin injection. At around 35 to 40 my wife says that she can tell a difference in me although I don’t always notice it. The lowest level I have tested at was 20. I definitely knew something was amiss but was still well enough together to run the test twice because I questioned it. From the feelings I have experienced I am pretty certain that I could not tolerate a level of 10 but perhaps I am incorrect? Is it literally POSSIBLE to have a BS reading of say 4 or 5 and remain conscious if the B-OHB is say 5 or even 6? My interest is merely academic and I would never attempt to get to these sorts of readings in other than a clinical environment.

  • Michael

    Thank you for your replies. Boy is there ever a lot of bad info on the Internet. One of the Wiki articles talks about the bodies ability to produce glucose. There is so much home spun advice from people who call themselves experts that it is pretty much a toss up as to whether or not people can sort it all out.

    Could you tell me if there is a process within out human system that REQUIRES carbohydrate to function? Would it be POSSIBLE in a clinical setting with adequate monitoring to maintain all bodily functions including brain function with a glucose level of zero?

    I recall reading years ago that a pure protein diet will cause one to lose weight no matter how much protein is consumed but that adding just a bit of carb will allow that protein to be utilized efficiently enough to gain weight. I am not certain why I believed this at the time I read it but I did. I assumed the cause for this was some pathway that absolutely required carb that could not be gotten around in any way at all.

    • Michael

      Dr. Attia…. I want to thank you for putting me onto the ketogenic diet idea. I have continued to do research on it via the Internet but find that I must do quite a bit of filtering to separate the junk from the good info.

      It simply amazes me that in 53 years of being T1D no one (including medical personnel) has ever mentioned it to me. It has always been about balancing insulin injections and quantities against carb intake and never about eliminating most of the carbs. This diet has already reduced my insulin need substantially and tightened up my BG readings tremendously.

      I’d still like to know the answers to those last couple of questions I posed but completely understand if you feel it inappropriate to answer.

      Your blog has REALLY great info for any T1D and I sure wish that I could somehow get it to the other 100s of T1Ds I have known throughout my life.


      • Michael, check out Richard Bernstein’s book if you have not already.

    • Jennifer

      Dear Michael,
      I’m a nurse-midwife and although this isn’t my area, I do remember that there are some types of cells (not many), including some types of brain cells, that do require glucose to function. Those particular cells are unable to use any other fuel and must have glucose. It’s not possible for humans to survive with a blood glucose level of zero, BUT we don’t require exogenous carbohydrate from food because we can make our own glucose, enough to supply those cells with what they need.

  • dlr

    You left out the social scientist in your anecdote:

    “look, all of the sheep in the world have turned black!!!”

  • Martin

    Peter, I’ve read lots of of your posts on how you structure the workouts, watched the video as well. One thing that I wonder about is how you handle stress. The problem seems to be that if you workout hard and often your body will produce cortisol and start producing glucose via gluconeogenesis. Is it less of a problem if you are keto-adapted? Have you tried supplements like e.g. curcuma or cissus which are reported to lower cortisol response? Thanks

    • Intense workouts certainly increase HGO and may do the same with cortisol. I think the question is, how long does this effect persist?

  • Roxana

    Dr Attia,

    Regarding the comment posted by Helga above, if a person has plateau in weight will exercise help? I have been in ketosis according to the ketone sticks (I am planning to get my hands on that handheld device very soon to confirm) for over three months and have exercised for maybe 3 days within this time frame (lol) and haven’t lost any scale weight and my pants are not considerable any looser. Should I be exercising? Will it mobilize my fat storage? Thanks

    • It might for some people, but it could easily do the opposite for others. One thing I’ve experimented with (and will write about at some point) is using intermittent fasting to break through plateaus.

  • Jesse

    Dear Dr Attia,
    Thank you for all the great information. I am writing with the hopes of getting some comments either from you and/or other readers with experience of being in ketosis. I have been in ketosis for about 6 weeks. I stuck with my normal exercise routine (5 days a week of things like biking, running, lifting, full-court basketball) during induction. I read LATER that keto-induction mixed with exercise could be tough–it was. But after two weeks I felt pretty normal working out. For the most part now when I work out I feel really good. And I love that I can go for a two or even 3 hour bike ride and not have to fuel at all while feeling strong (except at the beginning) the whole ride. I made some mistakes, such as not supplementing with enough sodium, potassium, magnesium, but as I started to take these regularly things like cramping, performance, and overall feeling would get better.

    I initially read Gary Taubes WHY WE GET FAT and started to go low carb (was fairly easy to do). He referred me to you at which point with hopes of losing a bit of fat and taking advantage of all the other benefits of a ketotic diet that you go into, I decided to try being in ketosis. I’ve also read Volek and Phinny, and spent a lot of time on various blogs. I’m really curious about what happens if I bump myself out of ketosis either for a short period or longer period. Will I have to go through a long keto-adaption period again? Will I just drop right back into ketosis as soon as I drop my carbs enough? Part of the reason I ask is that as the weather warms up it feels much harder for me to eat high fat and meat; it just doesn’t quite feel right to be eating burgers with bacon and cheese and passing up fresh cherries and berries. I also start wanting a bit more variety and flexibility with my diet. Another reason is that as much as there is a lot to like about being in ketosis, sometimes I want more flexibility, especially if I’m with a group or doing vacations with my kids. I know ultimately I have to just experiment myself but it’s great to hear form others as well.

    I would be interested to hear other’s experience on being in ketosis, and wonder if there might be a place on your website to post these?

    Thanks again for all your hard work. It’s been fantastic to learn about all of this.


    • It really depends on how “badly” you knock yourself out of ketosis. One meal of too much protein is pretty quick recovery – probably less than 24 hours. Three high-carb meals probably sets you back a few days. Not all carbs have the same impact, so it’s really quite nuanced.

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  • Aviv

    Hi Peter

    Going through your blog and reading EVERY single comment is the best source of information one can find. I really think that down the road (hopefully sooner than later) it is guys like you that will finally turn things around. Keep it up, as hard as it is, I know it keeps you very busy. The way I see it, fighting against these mega industries (farma, USDA,food industries etc…) will have to be hard, and by putting all this information out there for NO profit is making you a hero. Knowledge = Power. Thanks!

    Quick request, can you tell me (us) your TRUE blood glucose levels (if you have more reliable source other than your current devise) from the fasting state, say morning, to an hour after your typical meal and also 2 hours after (no exercise involved). Can’t find much information about “normal” levels for folks in ketosis. I am not taking it as a model, just curious.

    • Thanks for the kind words and encouragement, Aviv. My blood glucose varies quite a bit depending on activity and intake. I’ve measured leaves as low as 50 (after prolonged fasting) and has high as 135 or so after super-intense exercise, where hepatic glucose output is maximal. “Normal” post-prandial might be around 100 and normal fasting after 10 hours might be around 80-90 (for me).

    • Aviv

      Thank you so much. I really don’t want to open my mouth since I got “burned” before, but thing are going the right way, thanks to you.

  • Tom C

    Hi Peter,

    Before I get to my question, I want to let you know I love your blog and as a fellow engineer, the gritty details are awesome! Anyway, to my question: It is my understanding you continue to actively exercise regularly. Could you address the topic of harmful effects of too much aerobic exercise or “chronic cardio”? I have read several sources with compelling information regarding the harmful effects of too much cardio, etc. As a triathlete, I do my best to utilize interval training and weight training as much as possible, however there are obviously training days dedicated to a more aerobic workout. I want to continue my athletic endeavors, however I do not want to diminish my health along the way.

    Any feedback you are able to provide would be much appreciated.

    Thank you!


  • Kitzella

    Hi Peter,
    Have been voraciously reading your blog after finding you on the Web. I’m following the program outlined in “The Art & Science of Low Carbohydrate Performance”, and have been doing about 5% carbs, 15% protein, 80% fat for a little over a week. This is not a radical change as I’ve been very low carb for awhile, but it is my first attempt to get into nutritional ketosis. Feeling crappy, but I knew to expect that. Even with my fat intake up this high my blood ketone levels are usually steady at 0.3 or less, which is starting to get discouraging. I don’t have much energy, but would exercising help move this along? I usually do swimming, walking & P90X, but I’m still quite overweight.
    Thanks for your website, I’ve been desperate to get some answers on this stuff.

  • Dallas

    I assume your ketone levels on occasion vary from low to high within the optimum range. My question to you – or any readers who’ve made note of it personally – is whether or not you feel “better” with a consistently timed measured ketone level of say 2.0 instead of 1.0? Are there “degrees” of nutritional ketosis in terms of benefits, or are you either in ketosis or not, and by how much doesn’t matter? Thanks,

  • Susie

    Hi Dr. Attia,

    I am wondering if you have read any studies on the effects of potassium. I had been taking 90 mg in the morning and 90 mg at night due to painful leg cramps in the middle of the night. I am rethinking how much I am taking since it seems that the supplement is not made in a higher dosage than 90 mg. I am also taking magnesium since I understand they work in conjunction with one another. (For today I made a change and thought I would just take those supplements in the evening.) Thank you in advance for your thoughts.


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  • Susie

    am I going to hurt myself taking too much potassium or will my kidneys flush out the excess?

    • You should speak with your doctor about this, as I can’t provide medical advice on this blog. I would need to know more about your health to answer that.

  • Susie

    I understand – thanks for responding.

  • Morgan

    Hey Dr. Attia,

    First, let me apologize for the very long post.

    I have a few random questions, I would understand if you can’t answer them online, but would greatly appreciate it if you could. At the start of the year I went on a Ketogenic diet for about a month (felt amazing, clear mind, everything), but I needed to stop for various reasons. Anyway, recently I decided I wanted to start again, I entered Ketosis a couple of days ago (after realizing I was taking way too much protein, and hence reducing it).

    In this post you mention having more then 120-150g of protein could be too much to stay in Ketosis, with my current diet (67% fat / 5% carbs / 28% protein) I’m getting about 160g of protein per day, would this be a problem? I’d really hate to be on a knife’s edge for staying in Ketosis. (Also if it’s relevant, my fat is a little over 170g and my carbs are 33g – 13g net, 20g fiber). And I’ve had problems increasing my fat without increasing my carbs or protein and still having decent meals.

    Another thing I’m doing is taking a Krill oil capsule in the morning for the extra Omega 3 (was taking 2, but tried lowering it to 1), it seems to interrupt my sleep, I noticed this with Fish oil and swapped to Krill oil hoping it would be different. I generally sleep 8-9 hours a night, but when taking fish/krill oil I wake up 2 – 4 times throughout the night. Do you have any idea why this would be.

    And lastly, I never really been one to get hungry, even when on a high carb diet, now on a low carb diet I’m basically never hungry. You mentioned in one of your posts (sorry, don’t remember which one, I foudn this site yesterday and finished reading them today) that you eat when you get hungry. I understand that hunger is the body’s way of saying it needs more fuel, but should I still try and eat meals and the usual times (I have a full time job so if I don’t prepare meals and bring them with me it’s difficult to properly balance what I eat)?

    And on a side note, thanks for writing this blog, it has answered a lot of my questions and worries about the Ketogenic diet, and will hopefully help lessen the burden of my induction period 😀

    Ah, yea, sorry one more random thing. I get a lot of people asking “why are you on a diet”, and various forms of that question (I’m 5ft 11 and 70kg, and a fit(ish – I do a couple of “boot camp” workout sessions a week and a few hours of football every couple of weeks). Is there any term I can use that will stop people asking questions (like Vegan, Vegetarian, ‘I don’t believe in murdering carbs unnecessarily’)?

    Thanks in advance,


    • Thanks for your questions, Morgan. I’ll try to address many of these when I do my (hopefully soon) series on everything I’ve learned in 18 months of ketosis.

    • Morgan

      Awesome, I look forward to it. I do have another question which would be awesome if you could add it to the list 😀

      I’ve noticed a lot of sodium in a lot of the high-fat foods, is that something I need to worry about? (I’m still within the normal range – about 1750mg), but that’s much more sodium then I was getting on my old healthy version of a high-carb diet.

      I’ll be on the lookout for that new post, and keep up the good work.


      • This question has actually been 17 or 18 times in Q&A of various posts. Start with “what I actually eat.”

  • Darrol

    Dr Attia, I follow a ketogenic diet but am a practicing judoka, which requires quit a bit of anaerobic work. Would there be a benifit to carb loading the night before a competition? I assume my energy use would be primarily glucose, but would my metabolic flexiblility for burning fat go down remarkedly or would I still have the flexibility and an easier time accessing fat for for energy? Or is there a lag period in which my body can form ketones and avoid quote “hit the wall”? Just curious, I haven’t noticed much fatigue difference on a ketogenic diet, which I mostly have been following for the last 2 years., just hoping for some kind of advantage. Bodybuilders cycle low carb and intermittent high carb, but for different reasons. I was wondering if there is a advantage to this strategy for anerobic athletes. Or should I just stick the ketogenic diet, I think I’ve been on it long enough that my body has gotten good reloading muscles through gluconeogenisis. But is it enough? Has anybody loooked into it? I can’t seem to find the answer ? Sincerely, Darrol Hval

    • I’ve never seen a study that specifically addresses this question, though it’s very easily testable. Studies have looked at variants of this question, but not the exact question (at least to my knowledge). My “gut” for what it’s worth says probably not, as a carb load will take you out of ketosis, thereby confusing your body, which has already adapted to oxidizing fat first, and turning to glycogen only when necessary. You may be interested in experimenting with super starch, though.

  • Darrol

    Thanks for your response, I will give the super starch a try. Darrol

  • Shawn

    A comment and a question.

    Comment: thank you for putting all this information out there, Dr. Attia. My story is a bang on duplicate. I’m a cardio machine, 2 black-belts and well over $100,000 over 12 years in gym fees, personal trainers, nutritionists and eating programs. Oh, and I’m fat. The most fat I ever gained was cycling 2 hours a day for a month and a half. Anyway, I’ve been in ketosis for about a month and a half and I’ve already started to see results, for the first time in over a decade. I’m just SO frustrated that I didn’t know about this when I was 25 years old. Glad I know now.

    Question: I went out of ketosis last week (friends over, non-friendly meals, etc), but immediately went back to eating properly. Typically, I get back into ketosis in a couple days, but not this time. I was still testing completely negative 5 days later. I was also busy with a couple projects and didn’t work out in that time. This morning, I tested negative for ketosis, but went up for a workout, and when I came back, I tested again, and I was in ketosis, finally. Does the workout interact with ketosis in such a way that it would help kick-start it again, or was this just coincidence? Thoughts?

    • Yes, workouts can impact the amount of ketones in your system, in both directions. Below threshold stuff tends to increase B-OHB, while above threshold tends to reduce B-OHB, probably by increase HGO.

    • Connie

      It is my understanding that ketone strips do not necessarily work long term for every one. If you are drinking enough water, your urine may be too dilute for ketone strips to work and once you have been in ketosis for a while, your body is using the ketones for energy and not spilling as many in the urine. I don’t know this for a fact but I have read it. Maybe Peter can shed some light on this.

      • Urine strips are qualitative, so I don’t use them. Your point is valid, though, because it’s quite likely that what you measure in the urine is not reflective of what’s happening int he blood.

  • Scott B

    Peter- I found your blog via reading Gary’s. It is very exciting to find a blog loaded with discussions around training and sports performace. My wife gave me a version of “less not thin” as “you should find some races or something to train for”. So I did, but the weight only slowly came off. Then I read Gary’s WGGF and was knocked over. When I saw the biochemistry laid out, I switched my diet that night. I have since dropped 30 lbs and MTB racing is much easier. I have struggled to find the right training and racing foods to eat on the bike so please keep posts about these coming.

    Your post on the VO2Max was fascinating. Have you looked at any of the work by Phil Skiba (he also seems to like calculus)? and his recent study on recovery

  • Hi Dr. Attia,

    I am relatively new to low carb and have a couple of questions. I do believe in its principles, partly because I went on my first ever Atkins diet at age 8 with my mom, so I feel like I’ve been raised in an Atkins-esque philosophy, even when I didn’t practice it.

    I accidentally removed sugar and processed foods from my diet when I lost my taste buds 3 months ago: no flavor, no point in eating the junk! About a month later I removed all starches, including tubers & legumes (except a rare bite of peanut butter). I eat meats, fish, poultry, cheese, nuts and a ton of fibrous veggies, as well as olive, coconut oils. I eat the odd berry and low carb yogurt (really ,the only processed food I eat). I am trying to keep my proteins down to about 80-120g per day. When I’m careful, I’m at about 50-60g carb and the rest is fats. I am 5’6″, 48 year old female. Maintaining a 90 pound weight loss from years ago. My last hydrostatic bodyfat test has me at about 140 pounds and 24% bodyfat. Of course I’d love to lose those last 5-10 pounds. My workouts vary wildly but I usually work out 5 days a week and I do emphasize weight-training. I enjoy tabata and circuits too and don’t do much in the way of endurance or steady state anything. (If you follow the link to my blog, you can see a few before and after photos etc or my IG feed ). OK enough background. Here are my questions:
    1) I was once told that if I ‘hang out’ above my measured Lactate Threshold (144bpm) I will ‘burn muscle’ and have always held to this like gospel- is it true? And is it true whether or not I’m in ketosis?
    2) I felt great when I cut out the starches and sugars – for a couple of months and I think I may have thought I was in ketosis, but now realize that there is no way that I could have been. Recently, I tracked my food to see what my macros really were, and as i said- I was at about 50-60g carbs/day and that was by not-restricting nuts and fibrous veggies to the point where I would have felt dismal. Concurrently I started feeling ‘blah’ like “is this really worth it?” Is it really true that ketosis is binary and that you can’t have benefits in a non-ketogenic, yet still-low carb level?
    3) Have you ever heard of anyone breaking out in a rash when going lower carb/higher fat? It could be very coincidental to some sunscreen I used, but just curious if you’ve ever seen this happen.
    4) Is there a variance in how long it takes to get into ketosis? and is there any value at all (or detriment) to carb-cycling throughout the week? Or does it just mess with your mood and sense of well-being and activity level? I’m pretty sure i could cut back my huge salads every other day or so, but I don’t think I can live my life without them forever. Makes sense?
    5) Did you ever do your self-experiment where you were going to ‘up’ your carbs? Curious how that went?!

    Thank you for listening to my ramblings, and thanks in advance for your response. I really really really really want this to work, but I’m sort of starting to get to a turning point where I have to decide whether to push this envelope further (am I just being impatient?) I’m also a bit bummed because my blog used to feature so many low-fat, high-protein recipes that now I don’t want to freak out my readers with high fat, low carb, mod protein recipes!! 🙂

    • 1. Not true
      2. No, plenty of benefits to being non-ketotic LC
      3. Not that I’m aware of
      4. Typically 2-3 days without fasting
      5. No yet

    • Thank you for your answers. Re. #4. What about WITH fasting? And how many hours of a fast?

    • Also, re. #1: Can you please help me understand the mechanism by which the body functions above LT? And since we like the numbering system, I’ll just ask my followup question this way: What does the body use for fuel above the LT in the following conditions?

      1. Non-Ketoadapted person, but fed (carbs, prot, fat mix for example)
      2. Non-Ketoadapted person, but fasted
      3. Keto-adapted person, but fed (fats and a bit of protein)
      4. Keto-adapted person, but fasted

      Are there lab studies on this in the literature? When I did a search for it a while ago, I found nothing, but perhaps I didn’t have access to the best sources?

      By the way- thank you for being so hands-on and replying to most of your comments! It’s really helpful. You are a super busy guy and we know that this takes time and effort on your part.

      • Deb, above LT, the body moves increasingly towards glycogen over fat. The ratio is estimated by the RQ (= VCO2/VO2). Very easy to get this test done on yourself. Look at my post about it.

    • Thanks again for your response. I re-read your post and it makes much more sense to me now. I had forgotten that we have 1000+ calories stored as glycogen. So I’m guessing that the guy who told me that I was ‘burning up my muscle’ above my LT must have misunderstood the energy systems and use of glycogen. In practicality, however, it does make some sense to spend some time below the LT to burn fat rather than glycogen. I’m guessing that this is why HIIT can be beneficial (for other cardiovascular reasons as well, of course) because you still get a great workout with a big calorie burn, yet you can burn more fat (though less overall calories) than had you just hung out above your LT the whole time. Anyway, thanks for the great blog.

      • This is a very important and awfully misunderstood topic. Sometimes I want to start a separate blog devoted to this topic! Of course, that would require a new life, so hopefully I can squeeze stuff into here, now and then.

  • Catherine

    I am wondering whether slow walking for two hours each morning will help slim down my bulky legs and help me burn fat. I am not worried about calories i am just wondering if it helps burn fat and slim down muscular legs

    • I have zero doubt that 2 hours of slow walking each morning will make you feel much better and, ultimately, nothing matters more than that. Whether it actually helps you lose adipose tissue on your legs is entirely a different matter. I think what you eat (and don’t eat) will have a greater impact on that.

  • Pam

    In the hope-it-makes-the-cut-soon category of your articles is what you mentioned in this comment above: “There is almost daily increasing amount of data suggesting that ketones are particularly brain-healthy [and] can play a huge role in preventing and reversing dementia.”

    I do realize that NuSi launches today, that the blog/writing articles will take a quiet ride in the backseat for a while, that you need more time with your family, and more. Still, I respectfully raise my hand. My mother is 89 and experiencing this. Selfishly, I want to do all I can, based on rigorous science to avoid this sad, sorrowful state myself. I turn 60 later this year, one of those “other creatures biologically”. I always knew I was special. 😉

    • I know…I want to get there as soon as possible, too. Thanks for your patience.

  • Pam

    Thank you, Peter, for responding. Re-reading my note, I see I might not have been clear that the knowledge is hoped for to help me personally do what I can to avoid my mom’s fate, not thinking the good science will be of help to Mom. Congratulations on NuSI, and bravo that you are pursuing knowledge that will change the world. Blessings.

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  • Shawn

    Dr Attia,
    Over the last few months, I’ve noticed a strange little pattern. Just wondering your thoughts…

    If I work out daily, and maintain a high ketosis reading (between 60/80 on the ketositx), my weight loss tends to be slow, and plateau. I eliminate most of the carbs to get the high reading. Workouts include a 40 minute run, then weights and cardio strength. Total workout around 1.5 hours, intense, 4- 5 times a week.

    If I DON’T workout, BUT keep myself in ketosis at a lower reading (trace amounts of ketones, up to around 20/30), my weight on the scale starts to drop. During this time, I usually am adding a bowl of berries and cream to my diet at the end of the day, accounting for the lower reading.

    Assuming that in scenario 1 when I’m working out, I’m NOT adding the exact weight back in muscle as to keep the scale even, any thoughts on what might be happening? I suppose simple coincidence can be an answer as well. Just trying to figure the best long-term strategy.


    • Shawn

      …oh, and not asking advice “medically-speaking”, to be clear. Just asking if there’s a nutritional ketosis factoid that might line up with that. I gave the URL to my MD and we talk about all this stuff, FYI.

  • Michael

    I am frustrated at my blood ketone blood levels. I have been on low carb (<50 g) now for several weeks. I have lost weight during this time. However, I just got a blood meter and have been disappointed at the ketone levels after exercise. I do short, high intensity cardio three days a week and short, high intensity weight training three days a week. As an example, today I did 25 minutes of fast, "can't do one more rep" weight training that puts me in an anaerobic state for about 30 seconds after each set. When I am done I consume about 40 g of whey protein because I feel my muscles need to rebuild from the workout. I then eat a high fat meal of eggs, butter, coconut oil and cream for breakfast. About an hour after my workout I tested my blood ketone level, and it was only 0.3. I don't understand why this is so low. Is this because my workouts are too intense? Does it make a difference how long after a workout I test ketone levels? Thanks for any help you can give me.

    • Couple of things….yes intense workout suppresses ketone production and/or contributes to net utilization resulting in lower levels. See my series on the interplay of exercise and ketosis.

      Also, don’t fixate on ketosis unless you have a real need to be there. You can be perfectly fine without being in ketosis. So be sure you know why you’re trying to get there.

    • Nicholas L.

      Have you been checking your blood glucose as well, post-workout?

      Per Peter’s advice to self-test, I have been monitoring myself extensively on BG/B-Ketone levels just before, just after, and an 60-90 minutes after exercising (sometimes I take superstarch just after exercise, sometimes not—so far that appears to make little difference with my numbers). I mainly do weight lifting (HIIT style) and running (8-9 minute pace), 4-6 miles. I have probably a dozen such tests under my belt now; I want to double or triple that and run some statistics on it before I feel sure of my impressions.

      That said, here is where my data about myself is pointing me right now: I find that lifting blunts ketosis and spikes blood glucose the most for me, and that the shorter the lift, the “worse” the effect, in general. For example, I will see a post-workout BG of 120-180 mg/dL (from 70-90 mg/dL pre) and B-ketone drop of 30-50%. An hour later, the BG especially drops back, though usually not back to baseline. The B-Ketone level usually recovers much more slowly. The same effect is true of running to a lesser degree: shorter runs mean higher blood glucose and lower B-ketones at the end. And having a lower post-workout blood glucose definitely means that, an hour or so later, my blood glucose and B-ketones are usually a lot ‘better’ than they would be after a short workout. For reference, for me, a short workout would be 25-30 minutes. For lifting, a longer workout would be 35-40 minutes (that extra 10 minutes can make a big difference for me). For running, a short run would be 30 minutes, a long one would be 45 minutes or more. If I run for over an hour (which is rare), usually my numbers improve by the end of the workout and get even better an hour later (B-ketones up, BG down from pre-workout). As far as I can tell, high B-ketone levels are driven by heavy fat burn, so things that amplify that (like long workouts that really empty liver glycogen and require very a lot of fat burning) help a bunch.

      I’ve only been kicked out of ketosis once (down to 0.4 mmol/L), after doing a workout in very mild ketosis. I was only ‘out’ for a few hours. So I can’t speak to having that “issue” often, but I did want to say that, in my experimentation with nutritional ketosis and monitoring myself daily, I am finding that, almost regardless of what I eat (within the limits of 50g carbs per day or so), I can have spectacular ketosis (>2.5 mmol/L B-ketones) or very modest or low ketosis (0.8-1.0 mmol/L B-ketones). The thing that distinguishes the two states for me personally is exercise. On days that I exercise, the next morning I will be deep in ketosis. On days that I don’t, it’s usually not so great. Skipping 2-3 days of exercise leads to high fasting BG for me (85-95 mg/dl as opposed to ~70 mg/dl) and low fasting B-ketone levels for me.

      The upshot of that is that, in my personal experience over the last few months, physical exertion is a huge contributor to awesome blood sugar levels and heavy ketosis—even when it causes acute, temporary aggravations to these measurements during and shortly after exercise. So, my suggestion would be to MAYBE extend your exercise time by ~10 minutes, but regardless, to check your ketone levels before exercise and at a different interval post-workout—2 hours after, and also the next morning. See if you notice a pattern there.

      Also, one final note from me—it took me six weeks (!) of ketogenic eating to see my athletic performance recover to the point where my exercise was as good as before on a high-carb diet. I didn’t have the blood ketone tests available at that point, so I don’t know how that was. All my above numbers were taken after being in virtually uninterrupted ketosis for over 2 months. I definitely recommend sticking with the ketogenic diet for several months if you really want to see what it’s all about. I liked the diet from the start, but exercising was miserable and frustrating for, as I said, 6 weeks for me. After that passed, everything seemed better for me. Good luck, and thanks for sharing your experience. It’s interesting to read about how ketosis works for others.

  • Sam Martin

    Good Afternoon Dr. Attia,

    Thank you for your excellent and inspiring work (and research).

    I wonder if you would write an article in the short future 🙂 about what happens to the Cori Cycle once a person has been keto-adapted. I ask because I practice Chinese (internal) martial arts that requires me to hold diffucult postures from long periods of time which activate the Cory Cycle. This in turn, leads to the acumulation of internal power (that’s why they are called internal martial arts).

    I haven’t found anything on the Internet about it. Do keto adapted athletes still rely on the Cori cycle or something else kicks in?

    Thank you,


    • The Cori Cycle is still in effect in ketosis. This week I’ll be publishing a detailed post on ketosis.

  • Sam Martin

    Thank you Sir!

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  • dino

    Both insulin and glucose (probably by causing the secretion of insulin) suppress ketones. This is why, for example, consuming more than about 50 gm of carbohydrates per day and/or more than about 120-150 gm of protein per day makes it difficult to be in nutritional ketosis – too much insulin secretion.
    Is that total carbs or net carbs?

    • At the 50 gm level, this is closer to total.

  • James

    This study suggests some people may compensate for energy expenditure through exercise more so than others, and greater weight loss may be observed in those that do not have a compensatory effect from exercising. Maybe exercise induced weight loss may be effective in some, but not others.

  • Indy M

    Quick question if you have 15 seconds:

    I have been in NK for about 3 weeks now(as shown by Ketone Blood sticks; avg ~ 2mm).

    After energetic 30 min Cardio work(rope work mostly) my Blood Glucose which otherwise averages ~82, goes upto ~100. Does this indicate Ketosis is not fully achieved yet? I was expecting the energy expenditure to all come fat, I suppose.

    Thanks in advance!

    Indy M.
    Sunnyvale, CA

    • Indy M

      I reread your post(Part II) and the Glucose appears to be coming from my Liver, when I workout at a pretty high Heart rate. So the answer is found.

      I need to vary my workouts and check against the four/five heart rate zones I utilize, namely Aerobic threshold, Tempo, Sublactate threshold, Lactate threhsold and sometimes Aerobic Capacity(all Joel Friel’s terminology). It would be interesting know how the Hepatic Glucose output varies with the different Heart Rate Zones.

      Thanks again.

    • Nope. It’s hepatic glucose output. I did a tough 90 minute workout yesterday at 8 am (fasted). I ingested nothing but water during the ride. Glucose went from 85 to 135 by end of the ride (lactate was about 5 mM and B-OHB when from 1.9 mM to 0.6 mM).

  • Indy M

    Nope. It’s hepatic glucose output. I did a tough 90 minute workout yesterday at 8 am (fasted). I ingested nothing but water during the ride. Glucose went from 85 to 135 by end of the ride (lactate was about 5 mM and B-OHB when from 1.9 mM to 0.6 mM).

    Those numbers are in the ball park of what I am seeing. It is amazing that the Liver is managing to squirrel away enough Glycogen in spite of my <= 20 gms of Carb a day!

    Thank you very much! Thats good to know. I hope to find out by experimenting in what heart rate zone I have least Glucose rise/most Ketone fall. Hopefully in one of the midzones, say Tempo, which is close to my Marathon speed.

    Thanks for all your help.

    Indy M.

    • At some point, I’ll report on my latest metabolic self-experiments. I’m learning more by the day.

  • Nicholas Tidemann

    I am currently in the starting phase of entering ketosis, but there is a question of mine that remains unanswered. I do strength training regularly, both for health reasons and to get stronger, and I wonder what kind of effect ketosis has on that. I know a lot of people who work out to build a lot of muscle use ketosis as a way of losing excess fat after “bulking up”, but I wonder about all the other implications. More specifically:

    1. Is ketosis efficient at conserving muscle mass when eating at a caloric deficit? The body burning fat but not muscle, that is.

    2. Compared to a glycolytic diet, how easily does the body build muscle while in ketosis when eating at a caloric surplus? When not eating carbs, it would seem to me that the body doesn’t put on fat that easily, but unless you excrete the caloric surplus, it appears that the excess calories must be stored on the body in some way.

    Hope you have the time to answer, and thanks a lot for all the information and all the articles on this site! It really is of a different level than the average opinions of people in the dieting/bodybuilding scene.

    Kindest regards, Nicholas T.

    • 1. Not sure. I would not imagine it’s “best” or even “optimal,” but it’s certainly possible. Just yesterday I set a new record for fastest 6 consecutive flips of the 450 pound tire. Obviously, there is more to that than pure strength, but this is pretty demanding.
      2. The key, for me, is timing of protein ingestion. How much BCAA…when I take them…how much glutamine…when I ingest it…what kind of post-workout protein…how much… etc.

  • Joseph

    Alan Aragon said something along the lines of: fat adaption can potentially impair performance by reducing the activity pyruvate dehydrogenase which could thereby decrease the rate of glycogenolysis during times of high glycogen demand. Interesting, as I would guess that fat adaption, even on a moderate carb diet, would be beneficial for athletic performance. Have you read any studies on this?
    Thanks Peter

    • Not sure what the evidence is supporting this claim. One of the main defects in insulin resistance is just that (impaired flux through PDH), especially at the neuron. So I’m not sure how PDH impairment is being documented. Also, one would need to define “fat adaptation” a bit more rigorously to have this discussion. My definition may be different than yours.

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  • Alec


    You said, “In your case, I’d be curious to see what would happen to your BP if you did not, at least temporarily, supplement with sodium.”

    I’ve been ketotic ~8wks (<=30g) drinking copious amounts of sea salt in order to avoid feeling plagued. Salt works but, my bp has jumped to 143/86 from 127/80.

    If you had to bet, would say that it is more likely this happened due to 8 weeks of inactivity (physiological stress due to adaptation and mental stress due to finals) or over-supplementation of salt?

    Btw., def agree on that it takes at least a few miles to rev up. Wow, never thought I'd corroborate such subtleties. You are the man.

    • Hard to say, but you may consider only supplementing sodium (and magnesium) around long workouts, but not routinely.

    • Alec

      Peter, thank you. I would actually never supp. sodium, if it weren’t for utter malaise I feel without it (or something else). Even being sedentary is difficult under 30g of carbs for me. 8 weeks into nutr. ketosis and I still feel like I am “hitting the wall” 8-10hrs into any sedentary day (a dehydrated, nauseated, head-ache feeling). There is almost nothing I can do to stay up at that point; and I used to pull all-nighters back to back just 2 months ago. It’s like there is something fundamentally wrong with this ketotic metabolism. Anyway, I really appreciate your input. These random pangs of seeming “imbalance” are just getting frustrating, esp. for my workouts.

    • Filip Zawadiak

      Hello Alec, I had somewhat similar experience – even with months on ketogenic diet and huge weight loss I had high fasting blood glucose (90-100) and similar feelings you had before dinner…

      Few days ago I started to measure blood ketone levels, which were not that high (<1) and I started to supplement more coconut oil (2 tbsp). Within two days my ketones went over 3, few times maxing at 5 and in two days my fasting blood glucose did significantly fall down (60-70), as well as hunger etc. All of that with exactly the same diet.

      Possibly some people need that extra push that normal fat alone doesn't do… BTW, urine ketone strips max out after this change, before I had them in the middle of the scale. I will keep it like that for few weeks and then see if it's permanent…

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  • Jason

    It is common training dogma that a large post-workout dose of carbs can capture transient high levels of glycogen synthase in order to increase muscle glycogen beyond baseline. This is thought to better prepare the athlete for their next training session. If on a carb restriction diet and therefore without this dose, do you feel that high glycogen levels can be achieved by other means?

    Thanks for the excellent website and your humble approach to the science.

    • I’m less convinced of the timing need, or the so-called “window” effect. If the liver or muscle are deplete of glycogen, they will always have metabolic priority to replenish in the face of available CHO, long before DNL kicks in. Most people, of course, dramatically over-estimate how much CHO is necessary to “load” the system.

  • DareV


    I do apriciate all the hard work you are doing in educating us.

    In this blog entry you have answered to Nicholas Tidemann on March 18, 2013 with an answer saying: The key, for me, is timing of protein ingestion. How much BCAA…when I take them…how much glutamine…when I ingest it…what kind of post-workout protein…how much… etc.

    Would you be so kind and elaborate this? I am a pretty lean person and enjoying ketosis but I want to gain more muscle mass and gain strenght, stay in ketosis and also eat naturally, as my main goal is longevity and a productive life. I also wonder how come you are using supplements BCAA and glutamine when both can come from correct diet. Do you do this just because its less time consuming?

    • Dare, to address this properly requires an entire post, unfortunately. It will happen at some point.

  • DareV

    Thanks for a fast reply Peter, I cant imagine you still have time to answer us and doing everything else.

    One more question thou. I am still in doubts about builing muscle on a keto diet. Do you know anything about how process of builing muscle works and do you recommend any literature to me, about it? My biggest concern is that it is impossible (or at least very hard) to build muscle if glycogen stores are not full. The way I look at it, using only my regular Joe logic, is that after a hard workout body’s primary function around muscles is to refill the glycogen stores first (beside other – more important stuff) and only later it will go and build new tissue, does this makes sense or its completely off? I know timing is not an issue so its not mandatory to do this in 30min window (like most bodybuilding sites recommend), but if im on a keto diet I wonder how fast can we convert fat/protein to carbs and use that to refill glycogen?

  • Jeremy V

    Dr. Peter,
    If you’re primarily keto-adapted and you’re glycogen levels are depleted, how would you ‘top off’ the tank before a big event when you’re daily intake is ~50g/day? How exactly would you do that to ensure that you can last 10-12 hours just under Aerobic Threshold? Once that is set, sounds like SuperStarch pre-race and during is a smart practice to go along with electrolytes and some onboard fat supplementation like nuts and other fat portables. Hoping you can comment on this.

    • I use the actual delta of carb requirement to top of glycogen stores. Sometimes this is more than 50 gm/day. If I’ve estimated correctly (i.e., that I needed more than ~50 gm/day), I stay in ketosis.

  • Damon Amato

    how long did it take restricting carbohydrates before you were consistently in ketosis? I have personally restricted carbs to <30g/day for the past 11 days. Today I had coffee with heavy cream, and then a lunch of italian sausage, red peppers, spinach in a home made tomato sauce, and my post prandial ketones 75 min later were .2mmol/L. I was expecting 1-3mmol/L. I'm wondering if there is something you did that I have not done to get my body into ketosis. Thanks.

    • You are likely consuming too much protein. Switch to ketosis should take no more than 3 or 4 days.

  • leslie

    Question: Post 40mile ride/then 6 mile run/with weight lifting in the middle did precision test for glucose and ketones. Did eat four hundred calories of coconut oil/butter/cocoa candies I make with stevia and two ozs of cheese to replenish protein within 30 minutes of getting home and testing.

    Glucose 168! Ketones 1. How concerned should I be? Is this a byproduct of ketosis (>100 days) combined with intense exercise? My fasting glucose is usually 75 and post meal glucose 110 at one hour.

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  • Danny

    Hey Peter.. have you interpreted the results yet?

    • Yes, I think so. Addressed in recent posts.

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  • Emil

    I have been on LCHF for the last 5 years. However, for the last 4 weeks I’ve been eating to minimize insulin as much as possible to get a bit leaner. I would like to get to about 7% body fat.

    I eat according to the following rules. Rule 1 may override rule 2 and rule 2 may override rule 3 etc.
    1. Eat 100 grams of protein on days with 1 workout, closer to 150 grams on days with 2 work outs. Do not go over or under these numbers.
    2. Eat protein only when insulin is low. Insulin levels can be approximated by blood glucose or ketones.
    3. Do not eat more than 50 grams of protein per meal. Closer to 30 grams is ideal.
    4. When hungry eat fat.

    I also eat 1 tomato covered in salt at each meal.

    I go to the gym and lift weights 8-10 times a week (sometimes twice a day).
    I have huge amounts of energy all the time and even after my hour session is up I usually would like to keep going. I spend the whole day behind a computer and if I do not go to the gym that day I feel uncomfortably energetic. I often train having not eaten dinner the night before and not having eaten breakfast that morning. In this case I find my ketones are super high, I am very thirsty in the gym but there is no decrease in energy what so ever. One more thing, on a diet with a bit more protein and carbs (but still what most consider low carb) I would always get light headed after performing big exercises like squats or dead lifts, this never happens anymore.

    There certainly is an adaptation phase every time you lower carbs+protein but after you get past that you will never look back. I am a fat burning machine.

    • Very interesting experience, Emil. Thanks for sharing.

  • Rory


    You’ve got a great website here and I really appreciate all of your work here and elsewhere. Based largely on your recommendations/results, I have been on a ketogenic diet for a few weeks and I am feeling great and losing weight (hopefully fat, probably water).

    I would like to second the requests of others above for more details on how to build muscle while maintaining ketosis, with specifics around pre-/post-workout nutrition and ideal carb/protein sources. I am planning to enter a mass-building phase in a month or two and I’m a little overwhelmed by trying to optimize for muscle gains without “breaking” ketosis. All of the conventional wisdom for mass building (high protein, high carbs) is the exact opposite of a ketogenic diet. I’m thinking that the right combination of moderately increased protein and carbs (especially Superstarch) with optimized timing might be able to thread the needle between the two opposing diet plans. This would be combined with a fairly typical mass-building workout plan (e.g. high-rep heavy squats, no cardio, lots of rest, etc.). Have you ever tried to do this?

    • Rory, I just have no deep expertise in muscle building. I’ve never been a bodybuilder, so it’s probably best to look at stuff by Doug McGuff and others. Maybe Lyle McDonald, also. Mike Mentzer is also a thoughtful guy on this topic.

  • Brent Rice

    Hello Peter-

    I appreciate your willingness to answer so many questions. I have queried for this via your search bar as well as google so I hope it is not a question that you have previously addressed.

    Years ago, I took the supplement ZMA when I was into weightlifting. It did have a noticeable positive impact on my sleep. Fast forward to the present day, I am following (very successfully I must add) a strict ketogenic diet and rigorous swimming and dry land workout routine. Based on my results, I think I need to boost my magnesium intake via supplementation. I am considering returning to ZMA supplementation and am curious if the magnesium in this form (magnesium aspartate) would provide the same benefit. What is your experience and/or opinion on ZMA in general?

    Thank you in advance,


  • Max

    Nice Article. It’s so me, I’m a d1 college athlete with low hemoglobin levels around 8 or 9, I have cold hands every time (may have thalassemia but the doctor says I’m fine and just deficient in iron) I also weight train 5 times a week and lately I’ve been really tired and would even get headaches after finishing a timed mile, my hamstrings would burn so bad that I would slow down by like 50% and can’t keep pushing myself. I also get pounding in my head after doing an activity. Recently I got an iron infusion and feeling a little bit better but nothing significant. I wonder if it’s my nutrition and reduced carbohydrate intake that causes such low hemoglobin levels. I literally cannot sustain any high intensity activity. I’ve been researching my condition there’re sources that say that people get put on steroids in order to treat this conditioning.
    Could it be related to my carbohydrate intake? Should I eat more carbs or this is the medical condition that I have to live with? What would you recommend?


    • No way of knowing without doing a real workup. All hormones. But Hb of 8 or 9 is unacceptable for a young healthy person and should be treated (EPO, transfusion) if a source can’t be found and fixed.

  • Amanda

    Max have you been checked for IGA antibodies?
    I had low hemoglobin, headaches and fatigue, and I was on a low carb diet, eating lots of steak and still anemic. My doctor did a whole lot of tests and nothing was found, went to another doctor and right away she said “I think you are gluten intolerant” and she order some tests, the right tests.
    I went gluten free even before getting the results back. I felt better almost right away. The results showed I had very high levels of antibodies against gliadin.
    I must say I did not know gluten is in everything! I was not eating bread at all, but I was poisoned with gluten from other sources until I completely cleaned my diet. My hemoglobin is back to normal, I feel and look younger, have lots of energy, no headaches, I know now that low hemoglobin is common on celiacs, and people who are non celiac gluten intolerant; although I have no gastrointestinal symptoms, I was not absorbing iron from my diet probably due to inflammation in my gut.
    Even if you have negative test results, you could try going GF.

  • Lane

    I’d like to know if anyone else gets a debilitating muscle fatigue with the kind of exercise routine I have, and what to do about it. I’m male, 56, 6’0” 150 pounds, ~5% body fat. Was a competitive cyclist into my early 40s; now I just do relaxing 1-hour rides 6 days a week, and push one day a week, either cycling 24 miles with ~2000’ gain, or fast-paced (4+mph) hiking up a 3.5 mile 2300’ local mountain peak. Been doing keto for ~2 months. Now with keto as well as in the 15 years before keto, I experience unusually high muscle fatigue in my legs, especially upper quads, 1-2X/yr and lasting from several weeks to several months (I don’t feel it during normal daily activities, only when I do moderate or more exercise (70+% of MHR). I don’t think that I’m doing any high-intensity exercise that would explain this fatigue. I was hoping keto would eliminate this, but it hasn’t. I’m doing ~50g carbs, 100-125g protein, 85% fat; I supplement Mg, get enough sodium. Used to weigh 155 but I’ve lost 5 pounds on keto – not my intention; I was just looking for a healthier way to eat. Any thoughts on what might be happening to cause this muscle fatigue?

  • Peter Straka

    Hi Peter,
    suppose you were doing the workouts above without ingesting any carbs. Would you expect any symptoms, and if yes what kinds?

    • No symptoms today. Three years ago, may have been a bit light-headed at times.

  • Glenn

    Hi Peter, I discovered your site at the recommendation of my physician a year ago and what a life changer this has been. Can’t thank you enough. I am an avid cyclist and intend to do my first century ride this year (at 55 years old). Could you give my some advice on nutrition before and during the ride. This is my biggest goal to date and don’t want to blow it! Thanks again for your great work.

  • Larry

    Hello Peter. Thanks for this website. Has really helped me understand my body better and fit into some old jean sizes! Was curious about your Beta-thalassemia. I have congenital spherocytosis, which sounds similar to B-T in that spherocytes have reduced carrying capacity of hemoglobin (25%) due to their shape and there are fewer spherocytes (25% fewer) in existence because they are more fragile and the body cannot replenish. Bottom line is a “low grade” anemia, possibly resulting in a 46% decrease of oxygen capacity without taking into account body compensations. I know the body compensates to some extent, but would imagine there are some implications to the anemia, pertaining to energy systems, muscle types, potential compensations, etc. I’m not looking for personal information, just looking to see if there are implications that you’ve found on your journey and if so, where I might start hunting down background information. Thought for sure the low grade anemia might affect aerobic energy sports, but it seems like you do just fine. Seems like when my kids who are outrageously carb fueled at the moment, go into aerobic exercise, they have significant hurdles. Yet growing up, my brothers and sisters seemed to beat the anemia, with a pretty intense approach to aerobic activity. Almost seems to me that the intense approach probably keeps the bodies out of the aerobic zone, probably in the glycogen or perhaps even the phosphate based energy system. As we get older, much of what we become concerned about is helping our kids. Before I resort to the old tried and true “get out there and try harder” I wanted to try and understand what was going on a little bit more. Keep up the good work. Thanks again for the website!

    • Beta-thal trait does result in a reduced Hct, which does lower oxygen carrying capacity. In me, it’s about 10-20%. At much larger reductions like you describe, it would definitely make the aerobic ceiling lower.

  • Alexandra

    Hi Peter,
    I “discovered” your site after doing a search on ketosis and beta-thalassemia. I have beta-thalassemia and I am currently on a diet (Dr. Bernstein) where my ketosis levels are monitored 3x/week using urine samples and Ketonstiks. I seem to get trace amounts of ketosis and for some reason after 2 weeks i can’t seem to maintain the ketosis state, despite my best efforts to adhere to the diet. Your reference on your website seems to indicate that because of the beta-thalassemia my glucose levels might be high and therefore I am getting perhaps a false negative for ketosis? Also, I read that asparatame can elevate glucose levels as well?!

    Any advice you have about this would be MOST appreciated!!!
    Many thanks in advance!

  • Saskia

    Hello Peter,
    I am curretly keto-adapted and apply IF (leangains). I have MS and am on the Wahls paleo plus protocol combined with the AIP and potato starch. At the moment I cannot stand but am doing excersizes at the rehab-centre to make it possible again. Now I start to feel lightheaded when attempting to stand
    What can I do best to tackle this?

  • Amir

    Hi Peter,

    In attempts to enter ketosis, I’ve noticed elevated levels of cortisol, which accelerate muscle loss.

    Have you compared cortisol levels between states of glycolysis and ketosis?

    If cortisol is not, in fact, elevated during ketosis, what strategy do you use to minimize cortisol production (and hence muscle loss) when transitioning from a state of glycolysis to a state of ketosis?

    Thanks to you, I’m better educated on ketosis and appreciate the time you dedicate here.


    • Well, your question is pretty complicated and don’t lend itself to a short answer. Short answer is that phosphadityl serine can keep cortisol in check.

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  • Chris


    I didn’t know you have thalassemia, I was trying to research the topic for a friend who is suffering from beta-thalassemia as well. She is experiencing anemia and general fatigue and conventional medicine isn’t much help. Can you shed some light on the subject? Or, do you have a post about this?

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  • Sara

    Off-topic… Isn’t the beta-thalassemia trait protective against heart disease?

  • Ron

    Every time I read this I wonder about your wife’s ice cream recipe. I am a t1 diabetic, been following strict low carb for over a year and been following a ketogenic diet since September. I made the transition to this diet for endurance training and racing which along with SS has been hugely successful in allowing me to maintain blood glucose control.mBut I digress…. Is it possible for you to share your wife’s ice cream recipe? I love coffee and ice cream but have not had it in over a year. My sweet snacks are essentially stevia coated roast nuts and butter cream frosting using Swerve in confectioners form.

    If you can share her recipe I would be most appreciative.



    • Ron

      That is a bummer.

  • Jack

    Hey Ron,

    Type ice cream in the search Bar. Use Ctrl F to go through the different posts.

  • Janice


    Thanks for all this terrific information.

    You mentioned your total intake during a 6 hour ride was 50 gm fat; 16 gm protein; 67 gm carb (of which 50 gm was super-starch), for a total of about 750 calories…but how many total carbs do you eat for the etnire day when you go on long rides to make sure you stay in NK….do you have to limit your carbs at other meals or do the carbs in super-starch and/or the carbs burned during the ride allow you to consume additional carbs throughout the day? Sorry if you’ve covered this before, there is just so much information I couldn’t find anything about this.

    Also, how do you figure out how many calories (and for that matter protein and fat) to consume on a ride given you are burning 750 kcals per hour. If you are in NK, I get that you will be accessing your fat stores to supply energy….. super-starch has about 100 calories per package and you consumed 750 calories during the ride – did you need these extra calories above and beyond the superstarch so you didn’t bonk?

    I’m a long-distance (female) cyclist who has been on a low carb lowish fat/calorie diet for about two months (same old story – trying to lose weight) and I’m having trouble with energy levels towards the end of a 100 km ride. I’m training for a 380 km weekend tour. .I do better on this diet when not exercising, but enjoy riding too much to stop….so far I’ve tried increasing my calories before rides (with eggs and a bit of cheese to stay in NK – I’m a vegetarian)…but with limited success…so I was wondering about trying super-starch, but then can’t figure out if or how I need to modify my daily intake of carbs and caloriies accordingly so I continue to lose weight.

    Also, I always thought ketosis meant fat loss, so I read your other post with interest on this topic and suspect I am one those people who do need to limit fat intake…so upping my calories for rides by consuming fat may be counterproductive. Holy smokes this is complicated!

    I realize I probably just need to experiment more, but any advice on how to balance all this would be greatly appreciated.

    • ugur yemez

      Firstly, Thanks very much for detailed explanation of your test results and experience 🙂

      Is there any answer for the above comment? Good question..

      Do you have any idea to use a gel (such as maltodextrine) in the middle of training? How does effect the insulin and ketone level?
      As far as I know, when we are exercising our insulin is blunted, (Z3 tempo ride or above for example..) we do not get a strong insulin response, so the insuling spike will be minimal even we use high glisemic content.
      Besides, UCAN super starch vs maltodextrine test result is only for resting state. There is no any test results for during the activity, so is there any advantage to use UCAN instead of any traditional gels during the activity? What do you think?

  • Andy Reed

    Hi Peter

    Just a couple of questions re: timing of blood ketone measurements. Post exercise, are you checking your levels immediately on cessation, or an hour or two post exercise? Also, for someone checking they’re in NK periodically, do you recommend fasting tests, or bedtime testing? Any thoughts?

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  • Tony V

    I know I am late to the show but really was intrigued looking over your site when I was researching low carb/ketosis and endurance sports. Being a 70.3 athlete, I had a short question that I didn’t come across yet. In reference to VO2 intervals or another similiar type workouts aimed at increasing FTP on the bike or pace on the run, how long (as a reference) till these don’t feel like I made a mistake moving to this type of diet…all my numbers have crashed…quite depressing actually…I am on week 2 and based on my training, carb depletion happened quite fast…also, you were first site that mentioned that ratio’s actually decrease carb intake instead of staying the same…

  • Tariq Khan

    Hi Peter, In this article you mentioned you consumed about 50g of carbs in a long-training session (6 hour bike ride). How much would you recommend during a race, say a Marathon? Would you consume more under those conditions or stick to your training practices? Somebody like Cordain recommensd something like 50-75 g per hour, which is way more than you are getting.

    • Can’t answer that question as it depends on the fat adaptation of the individual and the intensity of the effort.

  • Diogo Tortorello

    Hey Peter,

    Try adding pink Himalayan salt.. about a full spoon early in the morning and a little in your workout water. Thats pretty much the healthiest way to get all ur sodium needs and minerals.

    As far as Ketones measuring.. I can only get high readings (above 1.0) when fasting over 24h.. Seems like my normal numbers read from 0.3 to 0.6 through out the week, which I think is low, considering I eat almost no carbs and moderate protein. Today for an exemplo.. woke up and ran 11km in a fasted state.. and only got 0.6 on my ketone reading when got home. Should I need more time to get those readings higher?

    By the way. a year ago Ive done a full ironman totally fat adapted… no carbs, nos gels.. only mct, pink salt and some protein during the race.

    • Very impressive, Diogo. What do you think makes the Himalayan salt unique?

    • Bob Niland

      re: What do you think makes the Himalayan salt unique?

      I’m not Diogo, but it may be more about what’s NOT in it, than what’s in it. The trace minerals may be more elegant than essential, but are probably not harmful if they are representative of concentrations in the original ancient sea water.

      If it’s coarse mined salt of credible provenance and stewardship, it lacks:

      • vs. generic “sea salt”:
      novel or excessive pollutants from modern evaporated sea water

      • vs. refined finely ground salt from any source:
      anti-caking agents, often grain-derived

      • vs. refined salt of any source and granularity:
      processing residues like ferrocyanide, aluminum silicate and ammonium citrate

      Coarse mined salt will also usually lack fortification with iodine, but condiment and cooking salts are not a reliable way to get iodine.

      Provenance and stewardship?
      Are we sure that Himalayan is not just Pakistani road salt?

      All food salt is sea salt. The questions are how long ago it was water, contaminants since then, what’s been subtracted, and what’s been added. My family uses a coarse pink Himalayan, but I couldn’t at the moment tell you a brand name.

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  • Andrew

    Interesting set of data Dr. Attia:
    From what I can tell, *High Intensity’ Interval exercise’ seems to work Best for a Carbohydrate based diet [ +71% Glucose (Glycogen stores releasing more Glucose into the bloodstream)].
    Whereas, an endurance, steady state exercise like Cycling or perhaps an hour on the Eliptical Machine, with a steady pace, would tend to work better, for a person on a Nutritional Ketosis diet (+238% B-OHB, indicating FA catabolism and formation of more B-OHB).

    Like you, I am very much fascinated by the human body, and the biochemistry behind it. I appreciate your insight, dedication, and personal knowledge that you have shared with regards to the Science of Nutrition.

    Personally, I am a practicing Physician Assistant who is admittedly out of shape, but is busy working to improve my overall health. My goal is to better understand the Science of Nutrition; so that,, I can help to improve the quality of life for the patients I serve.
    There is still a lot of misinformation being taught to patients by the medical community, with regards to diet and exercise and achieving optimal health.
    Fortunately, we have the opportunity of remedying this situation by collaborating with others, sharing our experiences, and fully understanding how our body works. Perhaps, one day Diabesity and Cardiovascular diseases will no longer exist.

  • John Landreth

    Dr Peter, I am late to this article and new to ketosis. I do crossfit workouts every morning and have been trying to lose fat for awhile now and nothing seems to work. I have been on a Keto diet for about 2 months with losing just a few pounds but fat seems to be thinning. I recently bought a blood sugar tester and strips for blood sugar as wellas ketones. I recently noticed the spke in blood sugare after a morning workout and wondering how it effects my ketosis. I am currently out of ketone test strips and unable to check but my blood sugar went from 91 to 150 after working out? Just trying to understand if I need to be concerned or change something?

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