August 26, 2013


Ketones and Carbohydrates: Can they co-exist?

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

Read Time 8 minutes

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

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

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

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


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Extreme example

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

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

So what did I eat that day?

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

What did this amount to?

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

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

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

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

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

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

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

What’s my point?

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

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

Final thoughts

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

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

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

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

Know your engine, first.  Then fuel it appropriately.

Photo by CloudVisual on Unsplash

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  1. Great post and very interesting.

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

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

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

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

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

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

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

  5. Peter,

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

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

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

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

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

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

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

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

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

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

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

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

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


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

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

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

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

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

      Thanks 🙂

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

      Thanks 🙂

  10. Hi Dr. Attia,

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

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

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

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

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

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

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

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

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

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

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

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

  14. Dr. Attia,

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

    The Best

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

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

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

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

    I’m so selfish. Ha.

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

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

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

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

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

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


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

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

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

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

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