June 12, 2018


My experience with exogenous ketones

Theory to anecdote: I decided to find out for myself if ketones could, indeed, offer up the same amount of usable energy with less oxygen consumption.

by Peter Attia

Read Time 10 minutes

I wrote this post at about the same time Germany won the World Cup in Rio de Janeiro in 2014. There’s been a lot of moving and shaking in the world of exogenous ketones since then, not to mention soccer. Looking back on my post, I still consider it relevant in terms of what exogenous ketones possibly can (and cannot) do for performance. In this case, to see if exogenous ketone esters provide me a “boost” by allowing me to do the same amount of work while expending less energy (and work at a relatively lower VO2) compared to no supplementation.

I’m getting an increasing number of questions about exogenous ketones. Are they good? Do they work for performance? Is there a dose-response curve? If I’m fasting, can I consume them without “breaking” the fast? Am I in ketosis if my liver isn’t producing ketones, but my BOHB is 1.5 mmol/L after ingesting ketones? Can they “ramp-up” ketogenesis? Are they a “smart drug?” What happens if someone has high levels of both glucose and ketones? Are some products better than others? Salts vs esters? BHB vs AcAc? Can taking exogenous ketones reduce endogenous production on a ketogenic diet? What’s the difference between racemic mixtures, D-form, and L-form? What’s your experience with MCTs and C8?

Caveat emptor: the following post doesn’t come close to answering most of these questions. I only document my experience with BHB salts (and a non-commercial version at that), but say little to nothing about my experience with BHB esters or AcAc esters. But it will provide you will some context and understanding about what exogenous ketones are, and what they might do for athletic performance. We’ll likely podcast about the questions and topics above and cover other aspects of exogenous ketones in more detail.

—P.A., June 2018


Original publication date: August 14, 2014

Last year I wrote a couple of posts on the nuances and complexities of ketosis, with an emphasis on nutritional ketosis (but some discussion of other states of ketosis—starvation ketosis and diabetic ketoacidosis, or DKA). To understand this post, you’ll want to at least be familiar with the ideas in those posts, which can be found here and here.

In the second of these posts I discuss the Delta G implications of the body using ketones (specifically, beta-hydroxybutyrate, or BHB, and acetoacetate, or AcAc) for ATP generation, instead of glucose and free fatty acid (FFA). At the time I wrote that post I was particularly (read: personally) interested in the Delta G arbitrage. Stated simply, per unit of carbon, utilization of BHB offers more ATP for the same amount of oxygen consumption (as corollary, generation of the same amount of ATP requires less oxygen consumption, when compared to glucose or FFA).

I also concluded that post by discussing the possibility of testing this (theoretical) idea in a real person, with the help of exogenous (i.e., synthetic) ketones. I have seen this effect in (unpublished) data in world class athletes not on a ketogenic diet who have supplemented with exogenous ketones (more on that, below). Case after case showed a small, but significant increase in sub-threshold performance (as an example, efforts longer than about 4 minutes all-out).

So I decided to find out for myself if ketones could, indeed, offer up the same amount of usable energy with less oxygen consumption. Some housekeeping issues before getting into it.

  1. This is a self-experiment, not real “data”—“N of 1” stuff is suggestive, but it prevents the use of nifty little things likes error bars and p-values. Please don’t over interpret these results. My reason for sharing this is to spark a discussion and hope that a more systematic and rigorous approach can be undertaken.
  2. All of the data I’ll present below were from an experiment I did with the help of Dominic D’Agostino and Pat Jak (who did the indirect calorimetry) in the summer of 2013. (I wrote this up immediately, but I’ve only got around to blogging about it now.) Dom is, far and away, the most knowledgeable person on the topic of exogenous ketones. Others have been at it longer, but none have the vast experiences with all possible modalities (i.e., esters versus salts, BHB versus AcAc) and the concurrent understanding of how nutritional ketosis works. If people call me keto-man (some do, as silly as it sounds), they should call Dom keto-king.
  3. I have tried the following preparations of exogenous ketones: BHB monoester, AcAc di-ester, BHB mineral salt (BHB combined with Na+, K+, and Ca2+). I have consumed these at different concentrations and in combination with different mixing agents, including MCT oil, pure caprylic acid (C8), branch-chained amino acids, and lemon juice (to lower the pH). I won’t go into the details of each, though, for the sake of time.
  4. The ketone esters are, hands-down, the worst tasting compounds I have ever put in my body. The world’s worst scotch tastes like spring water compared to these things. The first time I tried 50 mL of BHB monoester, I failed to mix it with anything (Dom warned me, but I was too eager to try them to actually read his instructions). Strategic error. It tasted as I imagine jet fuel would taste. I thought I was going to go blind. I didn’t stop gagging for 10 minutes. (I did this before an early morning bike ride, and I was gagging so loudly in the kitchen that I woke up my wife, who was still sleeping in our bedroom.) The taste of the AcAc di-ester is at least masked by the fact that Dom was able to put it into capsules. But they are still categorically horrible. The salts are definitely better, but despite experimenting with them for months, I was unable to consistently ingest them without experiencing GI side-effects; often I was fine, but enough times I was not, which left me concluding that I still needed to work out the kinks. From my discussions with others using the BHB salts, it seems I have a particularly sensitive GI system.

The hypothesis we sought out to test

A keto-adapted subject (who may already benefit from some Delta G arbitrage) will, under fixed work load, require less oxygen when ingesting exogenous ketones than when not.

Posed as a question: At a given rate of mechanical work, would the addition of exogenous ketones reduce a subject’s oxygen consumption?

The “experiment”

  • A keto-adapted subject (me) completed two 20-minute test rides at approximately 60% of VO2 max on a load generator (CompuTrainer); such a device allows one to “fix” the work requirement by fixing the power demand to pedal the bike
  • This fixed load was chosen to be 180 watts which resulted in approximately 3 L/min of VO2—minute ventilation of oxygen (this was an aerobic effort at a power output of approximately 60% of functional threshold power, FTP, which also corresponded to a minute ventilation of approximately 60% of VO2 max)
  • Test set #1—done under conditions of mild nutritional ketosis, while still fasted
  • Test set #2—60 minutes following ingestion of 15.6 g BHB mineral salt to produce instant “artificial ketosis,” which took place immediately following Test set #1
  • Measurements taken included whole blood glucose and BHB (every 5 minutes); VO2 and VCO2 (every 15 seconds); HR (continuous); RQ is calculated as the ratio of VO2 and VCO2. In the video of this post I explain what VO2, VCO2, and RQ tell us about energy expenditure and substrate use—very quickly, RQ typically varies between about 0.7 and 1.0—the closer RQ is to 0.7, the more fat is being oxidized; the reverse is true as RQ approaches 1.0


Test set #1 (control—mild nutritional ketosis)

The table below shows the data collected over the first 20 minute effort. The 20 minute effort was continuous, but for the purpose of presenting the data, I’ve shown the segmental values—end of segment for glucose and BHB; segment average for HR, minute ventilation (in mL per min), and RQ; and segment total for minute ventilation (in liters).

Glucose and BHB went down slightly throughout the effort and RQ fell, implying a high rate of fat oxidation. We can calculate fat oxidation from these data. Energy expenditure (EE), in kcal/min, can be derived from the VO2 and VCO2 data and the Weir equation. For this effort, EE was 14.66 kcal/min; RQ gives us a good representation of how much of the energy used during the exercise bout was derived from FFA vs. glucose—in this case about 87% FFA and 13% glucose. So fat oxidation was approximately 12.7 kcal/min or 1.41 g/min. It’s worth pointing out that “traditional” sports physiology preaches that fat oxidation peaks in a well-trained athlete at about 1 g/min. Clearly this is context limited (i.e., only true, if true at all, in athletes on high carb diets with high RQ). I’ve done several tests on myself to see how high I could push fat oxidation rate. So far my max is about 1.6 g/min. This suggests to me that very elite athletes (which I am not) who are highly fat adapted could approach 2 g/min of fat oxidation. Jeff Volek has done testing on elites and by personal communication he has recorded levels at 1.81 g/min. A very close friend of mine is contemplating a run at the 24 hour world record (cycling). I think it’s likely we’ll be able to get him to 2 g/min of fat oxidation on the correct diet.

The graph, below, shows the continuous data for VO2, VCO2 (measured), and RQ (calculated).

Test set #2 (ingestion of 15.6 g BHB salt 60 minutes prior)

The table below shows the same measurements and calculations as the above table, but under the test conditions. You’ll note that BHB is higher at the start and falls more rapidly, as does glucose (for reasons I’ll explain below). HR data are almost identical to the control test, but VO2 and VCO2 are both lower. RQ, however, is slightly higher, implying that the reduction in oxygen consumption was greater than the reduction in carbon dioxide production.

If you do the same calculations as I did above for estimating fat oxidation, you’ll see that EE in this case was approximately 13.92 kcal/min, while fat oxidation was only 67% of this, or 9.28 kcal/min, or 1.03 g/min. So, for this second effort (the test set) my body did about 5% less mechanical work, while oxidizing about 25% less of my own fat. The majority of this difference, I assume, is from the utilization of the exogenous BHB, and not glucose (again, I will address below what I think is happening with glucose levels).

The graph once again shows the continuous data for VO2, VCO2 (measured), and RQ (calculated).

Side-by-side difference

The final graph, below, shows the continuous data for only VO2 side-by-side for the 20 minute period. The upper (blue) line represents oxygen consumption under control conditions, while the lower line (red) represents oxygen consumption following the BHB ingestion. In theory, given that the same load was being overcome, and the same amount of mechanical work was being done, these lines should be identical.

The hypothesis being tested in this “experiment” is that they would not be the same. Beyond visual inspection, the difference between the lines appears to grow as the test goes on, which is captured in the tabular data showing 5 minute segmental data.


The most obvious limitation of this endeavor is the fact that it’s not an appropriately controlled experiment. Putting that aside, I want to focus on the nuanced limitations—which don’t impact the primary outcome of oxygen consumption—even if one were appropriately doing a real experiment.

  1. It’s not clear that the Weir coefficients used to estimate EE are relevant for someone in ketosis, let alone someone ingesting exogenous BHB. (The Weir formula states that EE is approximated by 3.94 * VO2 + 1.11 * VCO2, where VO2 and VCO2 are measured in L/min; 3.94 and 1.11 are the Weir coefficients, and they are derived by tabulating the stoichiometry of lipid synthesis and oxidation of fat and glucose and calculating the amount of oxygen consumed and carbon dioxide generated.) While this doesn’t impact the main observation—less oxygen was consumed with higher ketones—it does impact the estimation of EE and substrate use.
  2. In addition to the Weir coefficients being potentially off (which impacts EE), the RQ interpretation may be incorrect in the presence of endogenous or exogenous ketones. As a result, the estimation of fat and glucose oxidation may be off (though it’s directionally correct). That said, the current interpretation seems quite plausible—greater fat oxidation when I had to make my ketones; less when I got my ketones for “free.”

Observations from this “experiment” (and my experience, in general)

Animal models (e.g., using rat hearts) and unpublished case reports in elite athletes suggest supplemented BHB produces more ATP per unit carbon and per unit oxygen consumed than glycogen and FFA. This appears to have been the case in my anecdotal exercise.

The energy necessary to perform the mechanical work did not appear to change much between tests, though the amount of oxygen utilization and fat oxidation did go down measurably. The latter finding is not surprising since the body was not sitting on an abundant and available source of BHB—there was less need to make BHB “the old fashioned way.”

As seen in this exercise, glucose tends to fall quite precipitously following exogenous ketone ingestions. Without exception, every time I ingested these compounds (which I’ve probably done a total of 25 to 30 times), my glucose would fall, sometimes as low as 3 mM (just below 60 mg/dL). Despite this, I never felt symptomatic from hypoglycemia. Richard Veech (NIH) one of the pioneers of exogenous ketones, has suggested this phenomenon is the result of the ketones activating pyruvate dehydogenase (PDH), which enhances insulin-mediated glucose uptake. (At some point I will also write a post on Alzheimer’s disease, which almost always involves sluggish PDH activity —in animal models acute bolus of insulin transiently improves symptoms and administration of exogenous ketones does the same, even without glucose.)

In addition, the body regulates ketone production via ketonuria (peeing out excess ketones) and ketone-induced insulin release, which shuts off hepatic ketogenesis (the liver making more ketones when you have enough).   The insulin from this process could be increasing glucose disposal which, when coupled with PDH activation, could drive glucose levels quite low.

If that explains the hypoglycemia, it would seem the absence of symptoms can be explained by the work of George Cahill (back in the day; see bottom figure in this post)—when ketone levels are high enough they can dominate brain fuel, even ahead of glucose.

Finally, these compounds seemed to have a profound impact on my appetite (they produced a strong tendency towards appetite suppression). I think there are at least two good explanations for this, which I plan to write about in a dedicated post. This particular topic—appetite regulation—is too interesting to warrant anything less.

Open questions to be tested in real experiments

  1. Are these results reproducible? If so, how variable are the results across individuals (by baseline metabolic state, diet, fitness)?
  2. Would the difference in oxygen consumption be larger (or smaller) in an athlete not already keto-adapted (i.e., not producing endogenous ketones)?
  3. Would the observed effect be greater at higher plasma levels of BHB (e.g., 5 to 7 mM), which is “easily” achievable with exogenous ketones?
  4. Would the observed effect be the same or different at higher levels of ATP demand (e.g., at FTP or at 85-95% of VO2 max)?
  5. Would the trend towards improved energy efficiency continue if the exercise bout was longer in duration (say, greater than 2 hours)?
  6. How will exogenous ketones impact exercise duration and lactate buffering?
  7. Why do exogenous ketones (both BHB and AcAc it seems) reduce blood glucose levels so much, and can this feature be exploited to treat type 2 diabetes?
  8. Are there deleterious effects from using exogenous ketones, besides GI side-effects?
  9. What are the differences between exogenous BHB and AcAc (which in vivo exist in a reversible equilibrium) on this particular phenomenon? (Work by Dom D’Agostino’s group and others have shown other differences in metabolic response and clinical application, including their relative impact on neurons.)

Photo by Alexey Lin on Unsplash

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  • Richard

    Very cool. Would seem to support the hypothesis that a ketogenic state is advantageous for high altitude conditions e.g. sherpas eating Yak butter. Presumably all the King Of The Mountains contenders will all be chugging BHB salts next year…!

    • Maybe they already are…

    • Martin

      I would be more interested in seeing climbers attempting 8k summits switching to a ketogenic diet and/or consuming BHB salts.

      • I discussed my (subjective) experience cycling experience on Mount Evans (highest paved surface in NA) in NK in the video from the talk at IHMC.

    • Brooks

      I was trekking in Nepal two weeks before before the blizzard-avalanche. I had been eating LCHF and lost 20 lbs in about 3 mo. Going up hill at 12000 ft. challenged me. We met some trekkers who had just come over that mountain pass. Some hardy British mountain bikers were there too. It was hard to stay low carb on the available food. Yak steak is very tough!

    • Ron

      Hi Peter and everyone.
      I became fascinated with diet and ketones recently and found a ketone suppliment that I can attest is having some amazing results. It tastes great and I take it once a day. I have lost 8 lbs in 2 days and as you stated it does reduce appetite. I look forward to further posts and your research. Do you plan on expanding your research to ketones and diabetics and Alzheimer’s?

    • Nilla

      Hello Peter,

      Company Pruvit have come out with an exogenous Ketone powder drink called KetOS,
      I wonder what you think of it. Their ingredients are MCT oil and betahydroxybutyrate, natural flavors and Stevia.


    • corleyma

      What source of BHB mineral salts did you use? This would be greatly informative for others looking to experiment with exogenous ketones. Specifically, a recent study published in Nature (http://www.ncbi.nlm.nih.gov/pubmed/25686106) implies BHB supplementation may be particularly helpful in patients suffering from disorders like gout. However, the supplement market being what it is, information about which suppliers provide reliable sources of BHB salts would be helpful.

    • Mark

      in response to Martin’s comment – I have been climbing 14,000 peaks here in Colorado every year for the past 20 years. Last year I climbed Wetterhorn Peak and Uncomphagre while in ketosis (first time – in the past I’ve always “carb-loaded” prior to climbing).

      I was not sure how it was going to go. But to my surprise, I summited without the usual dizzy spells, light nausia, light-headedness that I typically felt above treeline. On top of that, I didn’t feel like I needed to stop and snack. Didn’t grab any energy bars. I brought a bag of cashews instead and ate some at the summit. But energy was noticeably higher, both mentally and physically.

    • Maged

      Hi Peter

      I have been trying to keto adapt for 2 months
      Using glucometer freestyle my ketone levels can range anywhere between 1.5 and 3 mmol ONLY if I am
      Constantly eating fat every 2 hours.

      If I don’t eat for more than 3 hours my ketones drop to .3
      But when I wake up I am at .6

      Is this normal if keto adapted??

      I have 80% fat 15 % protein age 5% carbs break down of macros??

      Also why do ketones go down after a weight session or even half hour bike ride ??

      Please help

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  • Ian

    This is gonna fuel Durianrider’s fire lol.

    • Christopher Grove

      Do we care? *grin*

    • Ian

      absolutely not! Although, I do get a good chuckle out of his nonsensical videos

  • Cool. These tests are throwing up more questions than answers, but it’s something I’ll be most interested in over the coming years:


    The first thing anyone will want to know is if they are a decent enhancement, just how much of a stacking effect is there with nutritional ketosis and keto-adaptation – if any?

    I’ve read/watched/listened to everything Dom has put out there, I reckon he’s 2015’s keto-sports guru, but the data on his war fighters and hyperbaric rats is still posing more questions than answers again.

    For anyone wondering, the r/ketogains and r/ketoscience subreddits are on the forefront of VLC performance and the geeky stuff on how and why.

    • Always my intention, Ash…questions >> answers…

  • I could of swore that you said your next write up would be about quantifying insulin sensitivity like 3 blogs ago! But I must admit I really appreciated this one and am just thankful that you write this stuff for us! It has really gotten my mind thinking of the possibilities. Thanks.

    • I know, I know…it’s 3/4 written on my desktop. This tells you how difficult a topic IR is…I’m not sure how to write about it.

    • Jane

      Thai is very interesting. Thank you.

      As just an ordinary, aging Jill out here, I hope that some day you do find the time to write about the implications for treating dementia.

      Is it only for Alzheimer’s dementia that the ketones may be helpful? Does anyone have any clues?
      What about other forms of dementia, such as micro-vascular and frontal lobe dementia?

      I still look forward to learning what you have to say about IR, and also medical interventions to lower LDL-p.

      Thanks again.


      • I’ve already alluded to this in previous posts (and this one).

  • Thanks for this Peter, whenever you post something new I feel like a kid on Christmas morning…LOL
    With my training I have found that my lactate threshold heart-rate from prior to being ketogenic to now is a difference of 30bpm higher being in ketosis, so I am very interested in knowing the difference from using exogenous ketones. i.e. testing LTHR before and after. Also me being a type 1 diabetic for people trying to use ketone esters or salt to boost them into ketosis, specifically overweight people that are insuin resistant, what would the implications be for overdosing and effectively putting them into a false state of ketoacidosis?

    • This test didn’t tell me anything about LT because the intensity was not high enough. One could make a theoretical arguments that NK, if MCT transporters are upregulated, could produce more lactate tolerance, but that could also turn out to be false, since it’s really the hydrogen ion, not lactate per se, that causes issues. (MCT transporters transport both BHB and lactate.)

  • I saw your Ted talk and am very impressed with your perspectives. I came across this on my Facebook news feed and have to admit I was lost at ‘exogenous ketones’. You may want to provide a better disclaimer that this is for medical students or whoever your target audience is, or at least a very clear summary of what this study actually proves. I love reading up on health and nutrition and recently switched to a low carb diet (not yet on a ketogenic diet), but couldn’t get what this was all about. Sorry!

    • Christopher Grove

      Michelle… Peter’s target audience is whomever thinks all this cool! 🙂

      (and possibly those who ride Pinarello bicycles! lol)

    • Daliza

      I agree with Michelle. This is Greek to me, but I am interested in a lay person’s version of these theories. I feel like my Type II diabetes is misunderstood, and that I may also be a victim of metabolic syndrome. This is what has led me to your blog, Peter. Your TedMed talk was very inspiring, and I understood most of it. Just checking around tonight to see what else you have put out here for us diabetics. I want to share this info with my doctors, but don’t think I can fully explain what you are telling us. Do you have a blog for others that are not medically trained.

      Thank you for what you are doing. Someday, the world will be a better place because of you and your teams of rivals!


    • Dana

      Exogenous = made outside the body while endogenous = made by the body.

      I’m not a medical student. Never have been one.

  • I think your work is fantastic and we need more open minded doctors who are willing to look beyond the food pyramid. I just suggest identifying who the target audience should be here, as this is beyond the typical understanding of the general public. 🙂

    • I don’t have a target audience.

    • bob

      You sound like you’re familiar with a lot of Peter’s articles but, if not, it’s really worth reading them. A small number of them have been over my head, but then I’m not a hardcote athlete or in ketosis, and it’s more technical articles on ketosis I’ve struggled with. Oh, and the cholesterol series, but I probably can’t afford to get the right tests done regularly anyway.

    • Michelle Jones

      I’ve read a number of these articles, and am very happy that we have a highly qualified doctor who is encouraging a ketogenic diet (and is proof that someone can thrive on it). Articles such as this one tend to be so technical that I couldn’t even understand the main point expressed (and aren’t any scientific studies supposed to have a clear hypothesis spelled out in the beginning?)

      I guess my concern is that Peter has the opportunity to reach many, many people about the benefits of low carb diets. Without more explanations provided on the technical articles, many people (especially the ones who may benefit the most and need the most education), may tend to automatically scan over the article and decide that ketogenic diets are too complicated. Perhaps it’s my language degree , but I was taught to always know your audience and the implications that your writings will convey. Peter has the opportunity to effectively reach many people, and I encourage him to take advantage of that. 🙂

      • Michelle, I appreciate your point and am honored that you hold me in that regard. However, I’ve chosen a very different path than being a “diet guru” who writes to the median. My work is really taking place in two arena: first and foremost at NuSI (BTW–we’ll have a completely re-done website up in a few months). If you really want to understand what occupies me for 75 hours each week, spend some time there. The second place is in my clinical practice. If NuSI is a very public presence, my clinical practice is the exact opposite. Very small and very niche.
        So where does that leave the blog? Well, to be honest, I shouldn’t be blogging for 2 reason: 1) I don’t have the time for it (168 hours in a week: 75 on NuSI, 10-15 on clinical work, family, training, sleep takes up the rest), 2) it’s creates confusion around my role as NuSI. No disrespect to “bloggers” (many of them are very good–better than I could ever be), but there should be no confusing what I do at NuSI with my personal blog.
        So I guess there are only 2 options for me on the blogging front: none at all, or doing what I’m doing. I’m simply not willing to put any more time into this endeavor relative to the work I have to do.
        Lastly, as other commentators have discussed, if you want everything served up in easy-to-digest blog posts, you’re unlikely to experience growth. I think it’s rewarding to be constantly challenged by new information.

    • Tim C

      Michelle – this is pretty heavy stuff, but I don’t think one needs to be a MD to understand it. I’m a computer programmer, and I’m glad this information is here and isn’t dumbed down; in other words, if it’s on Dr. Attia’s website, and I don’t know what it is, that just means I need to do my homework to understand it better. The whole point of trying to understand something better is to learn something you don’t already know.

      It is challenging, because a person really needs to dig into what cells do, what metabolism is, and the fantastic biochemical orchestra that plays within the human body. As mentioned by several other commentors on this post, sometimes answering one question leaves you with more questions…

    • Mark

      Hi Michelle,

      I’m not an expert in any of this either and I understand your reaction. This is not “diet-doctor” stuff. The essence of what Peter Attia and Gary Taubes are doing is trying to get real Science applied to diet and nutrition. Check out Gary Taubes “Good Calories, Bad Calories” or his shorter “Why we get Fat”.

      It’s really kind of disorienting because most people assume that Science must have all the big questions about things like what’s a healthy diet settled since they seem to be exploring all kinds of intricate details. Most doctors and nutritionist assume this too. If you google it you will come across a lot of MD’s and Phd’s insisting that it’s a matter of basic Physics (Laws of Thermodynamics) and calories are calories….and anyone suggesting otherwise is as scientifically clueless as a perpetual motion machine crank.

      Getting to the point of understanding that these sincere experts might just be completely wrong takes some work. It is quite possible to do though these days. You just have to back up and google terms and ideas you don’t understand. Once you can read research papers with reasonable understanding this stuff really opens up. It does take some work to understand the critical ideas behind how Science SHOULD work, how experiments SHOULD be designed but it’s necessary because often the work that people are basing their judgements on is quite flawed.

      I have the sense that this is a revolution in the culture of Science and Dr.Attia is giving us an unfiltered glimpse into the thinking. The practical diet part is pretty simple 🙂

      BTW exogenous ketones are just ketones you swallow or take in from the outside rather than produce by metabolizing fat. This it high performance endurance athlete stuff. From the description it makes Cod liver oil taste like Cream and Stawberries.

    • Yossi Mandel

      Michelle, I would encourage you to read the articles here from the beginning. When you hit a word or concept you’re unfamiliar with, check it on google or wikipedia. After a few times of reading these, you may start to feel comfortable enough to read the underlying research. It takes time to be able to translate the sometimes science-babble in papers to human language, but after a while it becomes like speed-reading, and you can figure out what is irrelevant and what to look up or look into further, and which studies are poorly structured and can be ignored. That is the true gain of being here, learning to read the science for yourself. I think we all have personal stories here of how we were able to make informed decisions instead of relying on hurried or poorly informed doctors.

      A personal example: A pregnant woman was diagnosed with gestational diabetes and told to take glyburide. A quick look at the research showed that glyburide has not been tested for use in pregant woman. That changed the decision to take it or not from an ignorant one to an informed one.

      A recent amazing example is here: http://mosaicscience.com/story/diy-diagnosis-how-extreme-athlete-uncovered-her-genetic-flaw.

      Don’t believe reading research is beyond the general public. It takes time to learn how, but it can be learned.

    • JK

      I’ve only two years of some college-level cell/genetics stuff under my belt, plus a semester on metabolic processes as a high-school exchange student (I studied lit and philosophy). After all these years, though, I’ve managed to forget everything. Nevertheless, Peter explains the key terms that might be unfamiliar to me. For example, his post “Ketosis – advantaged or misunderstood state? (Part II)” contains an argument that relies pretty heavily on interactions/comparisons between complex metabolic processes that go into producing fuel for cells. Yet the key terms are defined and placed into a context that makes it accessible for someone who didn’t attend a serious biochem course. Thus, I was still able to follow the general argument, even if I didn’t know how everything connects together. The post above is really interesting because it shows from start to finish a pretty neat concept for an experiment that treats an important issue for those of us who are involved in endurance sports. It’s an elegant, neat little unfiltered bit of experimental science that makes sense on some level. Again, he explained the key ideas without dumbing down the material. That’s something that at least this layperson values! Because when you’re thinking of changing fundamentally how you nourish yourself, it’s nice to see someone show their work when they’re advocating a view that goes against long-held conventions. I appreciate this.

  • Miriam

    Fascinating stuff! Thanks for this
    Question: how did it effect your appetite? Was your intake lower for a few hours? for a day? ‘
    I wonder what would happen if you did this while endogenous BHB levels were higher
    Can’t wait for your post on appetite, or the one on IR, supposed to be studying for boards but this is more fun 🙂

    • Huge suppression of appetite. I believe one of the first commercial applications of these products, once they can fix the taste, will be as a “diet supplement” that reduce appetite, rather than a performance booster.

  • greensleeves

    Wow Peter – this is the Dr. D’Agostino on Jimmy’s recent AHS 14 panel??!?!? I sat there during that whole talk stunned while those guys talked about how difficult, impossible, unsustainable, and dangerous nutritional ketosis was, particularly because you might have to take a magnesium supplement. During that whole show I was thinking how much MORE you knew, Peter, than any of those guys. What did I miss? So sorry, I still think YOU’RE the keto-king. 😉

    Also, Peter, lemme say that as a 40+ woman who tries pretty much to stay at 2.4 on the blood meter (which is hard of course because all the women who do this agree being on your period reduces your ketones no matter what you do because reproduction is a whole-metabolism event and not just a matter of a couple of hormones), my blood glucose is regularly between between 62 and 72, and I have to say I personally prefer the 62-65 range.

    But this does mean I avoid having conventional doctors do blood tests on me lest they freak out and I also totally avoid oral tolerance tests so I don’t have to break ketosis for 3 days to fake the results. I press about 475 on the leg machine doing Superslow and definitely can get an extra rep out at 62 versus 70. 😉 Just an anecdote of the female experience. 😀

    Best wishes.

    • Most of all I’m just so happy to hear that you’re doing Superslow!

    • Martin

      And how are your slow workouts going on? You mentioned earlier you started it. Any good results? Any benefits for your riding?

      • Great results, especially given the time investment now vs. then. Also, less injury. I’m doing something very modified from the “typical” slow protocol, but the principles apply.

    • Mikki

      I was at AHS14 too and can’t remember the take home message being ‘unsustainable, dangerous…’ with particularly taking a magnesium supplement… (which, as a nutritionist, I recommend most people take….)?? If anything they promoted it as an adjunct therapy with traditional cancer therapy (which the panel discussion was about. I had dinner that night in a group that included Miriam and Ellen on the panel and they are very pro ketogenic. Both Colin Campbell and Dominic very knowledgeable and advocate ketogenic diet… unless I”m really confused by your post here? (which I could be! lol)
      PS v impressive gym work btw.

    • Terra

      I’m curious what glucose meter you are using to trust such accuracy between 62 mg/dl and 70 mg/dl? I have tried several glucose meters at the same time and I have tried using the same glucose meter with two blood checks and I can easily obtain a 20% variance, as published data supports.

  • raphael711

    Hi Peter,

    Did you notice subjective changes in your effort during the tests? I’m guessing not.

    I’m writing an essay on a mitochondrial disorder (MERRF) and am fascinated about cell-specific (or tissue-specific) energy thresholds and how different substrates being oxidized or fermented affects their survival. It appears very relevant to Alzheimer’s disease. Along the same lines, Peter (over at http://high-fat-nutrition.blogspot.nl/2014/07) has a cool post discussing “Neuronal Fuel and Function” which echoes the question: which fuel does this cell (or that cell) prefer in these circumstances?

    Hope you find it interesting. [if you are not familiar with Peter – he’s a vet – and a very insightful dude]

    Here is a short extract: “Ketones and lactate do not drive reverse electron flow through complex I. Glucose can. Palmitate certainly can. What you want from a metabolic fuel depends on the remit of your cell types. Neurons within the brain preserve information by their continued existence. This is best done by burning lactate or ketones. NOT glucose and, of course, not FFAs”

    • No, not really. 180 watts is low enough that perceived exertion differences would be too low to notice over such a short interval. If the test was done at 275 watts for 20 min, or 180 watts for 3 hours, I’m guessing I could answer the question one way or the other. I’m familiar with Peter’s work. Smart fellow.

  • Luis

    I suffer mitochondrial myopathy and this is quite interesting. Is it possible to conclude that this will produce less ROS as a direct consequence of less oxygen being burned?

    • Great question. Add it to the list of things we need to understand.

    • pone

      Great question Luis. Peter, has anyone done any life extension research feeding ketone boosters to mice? Less oxygen used for metabolism should reduce oxidative stress on the electron transport chain. Less oxidation in mitochondria should reduce mitochondrial damage and might extend lifespan.

      • Not to my knowledge, but I have not looked specifically.

  • Norita

    Peter, did you feel any “smarter”? I have been wondering about the brain boost from added ketones. Could someone taking an important test supplement with ketone drink and be smarter for the day??

    • I definitely feel (subjectively) “smarter” when BHB is high, but this is true even when I was fasting (one meal a day), so no sure t here is anything unique about synthetic ketones vs. naturally produced.

  • Jonathan Christie

    Peter, that is really really cool!

    I Googled “what does KetoCal taste like?”, found on http://atkinsforseizures.com/forum/index.php?topic=9.0
    “I remember the 3:1 was rather bland and had a fatty/slightly metalic taste to me. I do know a family who’s son wouldn’t drink it and they had to add liquid stevia to sweeten it before he would.”

    Sounds considerably more appetizing that what you experimented with!

    • I have no idea what KetoCal is.

    • Cailin

      I have been doing ketosis for 6 months, and came across this, just this week, not public but I have been chating with them, prototype BHB mct oil, taste amazing, powder form, think they finally got it!! Have you or anyone heard of it?


  • Jonathan

    What did you end up mixing the ketone supplements with to make them less than awful tasting?

    • A cocktail of BCAA, soda water, and lemon juice.

  • Jim Kennedy

    Thank you for the information. I am struggling with how to use all your information to my best advantage. Having started Ultra-running about a year ago (1st 50K in Feb this year) I am trying to use more fat stores for fueling. Also my lean body mass to fat mass is not where I would like it. (eg 23%ish vs closer to 15%ish) Currently trying the avoidance of sugars etc. (avoidance means a lot lower than normal people ) I am a pretty smart guy, but I am not an MD. I am sure there are plenty of people in my situation. I wish there was an organization that could help one “hack” their diet to determine a healthy effective diet for that individual. From reading all your material you have taken a very scientific approach to this. Clearly different things work better for different people. Also you are giving out general information and not practicing medicine on this site. (I agree with the disclaimer and have read it, ) I don’t know how to quantify my progress and thus make course corrections.

    Sorry struggling a bit to phrase the question. If you come across an organization that does such consulting that might be a good general blog. Or how to search for such an organization. I understand if it sounds like requesting medical advice or an endorsement. Not trying to put you in that “box”. In any event just keep up the fantastic work. I appreciate all of it.

  • Robert Kazanjy

    Thanks for another interesting / thought provoking post. I’m too old be doing this sort of thing to myself but I really appreciate your self-experimentation and the fact you share you data!

    I also love your response “I don’t have a target audience”…. I guess a lot of people still don’t get the fact that this is your ‘personal blog’.

    I’m just happy I happen to be like where your blog goes. 🙂

    Keep it up…

    • Yup, pretty much a collection of musings. Maybe one day my kids will enjoy it. That’s about it.

  • twitchyfirefly

    I have been following Dr. Veech for several years, and have been in nutritional ketosis for almost 4 years to see if it helps a progressive peripheral motor neuropathy . To boost ketones I use MCT oil and AAKG (arginine alpha-ketoglutarate, which mostly tastes salty.) So I’m very interested in “Work by Dom D’Agostino’s group and others have shown other differences in metabolic response and clinical application, including their relative impact on neurons.”

    I do have one question about your experiment. Since you did the control session first, followed immediately by the test session, would you have depleted your glycogen stores at all, and if so, would that have had an effect on the second session?

    • Unlikely, given my RQ from the first test. I barely used any glycogen at all. None of this is to say the first test didn’t impact the second, but if it did, I don’t think glycogen was the reason.

    • icelandicstorm


      Your reasons for pursuing nutritional ketosis are inspiring! You mention in your post (2014) that you have been doing this for 4 years, so 5 years as of today. What are your personal observations so far?

  • Miriam

    Was your perceived exertion lower on the stuff?

    • This was only 60% of VO2 max, so for someone with my physiology, it would be hard to tell the difference. It would be interesting to examine at, say, 85-90% VO2 max.

  • Leah

    Dr. Attia,

    This may sound crazy, but do you happen to be visiting Phoenix? I swear I saw someone that looks like you today in a cafe and I almost wanted to come up and ask for your autograph ( your Got Grit blog is THE REASON I was motivated to truly change my life).

  • bob

    Superslow is like the kind of think Fred Hahn recommends, I guess?

  • Nice work, Will this mean faster times for endurance events? Why did you only use 69%, why not a time trial?

    • We’ll see, I guess. I’d like to re-test on TT.

  • Robert Coberly

    I’m sure I don’t know how to tease apart the acute and chronic effects of fasting, or CHO restriction, from the overlapping acute and chronic effects of moderately elevated ketone bodies in circulation. Have always thought of ketosis and CHO restriction together, with good reason as they have generally occurred together – until this advent of ketone precursors. Now the state of moderate ketosis, with no particular dietary restriction necessary, I don’t think we’ve seen that before. I appreciate the n=1 work, please continue as you can, and I really hope there can soon be more formal exploration of what is possible with ketone precursors. MCTs are useful but these ester ketone precursors appear to hold much potential to show what new metabolic possibilities may exist.

    In my work, I sometimes have compelling reasons to prescribe medications that, although they may be necessary, proceed to induce the metabolic syndrome in the patients. And of course this adverse metabolic condition has been increasing in incidence, overall. So in addition to exercise effects, I’m interested in possible ketone precursor benefits for metabolic syndrome, or of course for Type II DM.

    Induced ketosis may offer chronicaly lowered glucose and insulin levels, decreased appetite through increased brain malonyl CoA or other mechanisms, increased mitochondrial biogenesis, and through effects on the carbohydrate response-element binding protein mobilization, may further tip hepatic cell metabolism away from lipogenesis and toward lipolysis and beta-oxidation. So, could be good for fatty liver disease and related metabolic problems.

    I think CHO restriction is a dietary change that individuals at risk for the metabolic syndrome and its related illnesses should make. But I’ve been wondering if the acute change in appetite and metabolism provoked by ketone precursors could serve as a helpful bridge to beneficial dietary change in individuals who otherwise might not change their dietary patterns due to habit or food cravings.

    It would be expensive and months-long (to be done well) but I hope we can one day see a trial of diet and exercise lifestyle intervention in patients with metabolic syndrome or DM II, with double-blind rating and randomized assignment to a ketone precursor or a (suitably nasty tasting) placebo. Compliance with the study agent should not be difficult to objectively determine – measure ketones along with the other variables. Outcome measures BMI, waist circumference, A1C, diastolic BP, HDL, etc – maybe CRP and IL1, IL6 too.

    Please keep us informed on this area. If you were to pick a ketone precursor to trial as above – do you have an opinion yet which one would be practical to ingest?

    Rob Coberly

    • Yes, I think malonyl CoA is one of the mechanisms by which exogenous ketones reduce appetite. I also think the liver “sees” more ATP and that message gets to the brain.
      Not sure the answer to your question, though. From a regulatory standpoint the BHB salts are going to hit the market first (before BHB esters and AcAc esters), I suspect, since they already have GRAS approval.

  • bob

    Thanks. I only came across the concept recently, and I wondered what you thought about it. Who else would be worth looking into? I am pretty much untrained as of now, though not historically. Should I get right to it or start with something more “traditional”?

    Sorry for going off topic.

  • Chris

    I think much light is shed into this as long as you put it in an evolutionary perspective. I also think that this could be reproducible over longer durations as long as you keep providing exogenous ketones or as long as your body has enough bodyfat to sustain ketogenesis. Yet, tests need to be done!

    Great quantified experiment Doc 😉

  • David

    Informative post!
    I had a question when you stated…

    The latter finding is not surprising since the body was not sitting on an abundant and available source of BHB—there was less need to make BHB “the old fashioned way.”

    With exogenous ketones wouldn’t there be an abundant available of BHB?

  • Read

    This is really interesting. I can see the enormous potential for exogenous ketones to help with weight loss, and metabolic syndrome, but their potential effect on athletic performance and stamina has intrigued me. The fact that these ketones increase oxygen efficiency blows my mind. I immediately thought of the benefits for high altitude mountaineering like a previous poster, but it looks like they might work to bump someone in nutritional ketosis into a temporary metabolic state of super efficiency fueled almost entirely by ketones, so any endurance athlete in NK would improve performance by ingesting exogenous ketones immediately prior to exercise. I wonder about the mechanism for this oxygen efficiency? Really interesting stuff.

    It also made me wonder if it might help folks with COPD?

    Thanks very much for this. Fascinating and I will bet many athletes will take notice if they have not already. Do you know the timetable for when we might see the BHB salts hit the market?

    • Yes, assuming they can be made to taste ok and are found to not be harmful with long term use, there are many applications, as you suggest.

  • Herb

    I think ketosis is an emergency mode our bodies go into to remove all of the excess fat we have accumulated as a result of eating all of the sugar and carbohydrates in our modern day diet. Our bodies want to be lean and mean in order to prosper and breed and care for our young properly. Fight and flight. Fat we can’t do that effectively.

    • Tim C

      Hmm…personally, I think it’s more the natural metabolic state of human beings. If you imagine a scenario 50,000 years ago (or 200,000 or 1 million), abundance of dietary carbohydrates probably was the equivalent of no animal food source, and potentially starvation was on the way.

      This corroborates nicely with the insulin/enzyme/fat storage thought process, because lots of insulin promotes fat accumulation, which is what humans ought to be doing if they are lacking decent sustenance.

      Obviously, this oversimplifies it, because humans have always been opportunistic omnivores (early H. Erectus was probably a scavenger). Geography would have played an important role, as well, which is why fish was such a major dietary staple for so many Africans and Europeans for so long. It stands to reason that many of our biological adaptations would have gone hand-in-hand with high fish consumption

  • Charles

    Dr. Attia — thanks for such an interesting post. I always look forward to reading your latest post. You certainly sound like a busy guy, so I wanted to thank you for taking the time out of your schedule to put this information out there. I’ve learned so much from reading your posts over the years that I wanted to finally thank you; it has absolutely made me contemplate how I live my life.

    • Thank you, Charles. Appreciate that very much.

  • Neeraj

    Hi Peter,
    Thanks for all that you share with us.
    Just wondering if could help clear up some confusion for me. It was my understanding that after keto-adaptation, muscles primarily use free fatty acids as fuel and spare ketones for use by the brain. Is this accurate?
    If it is then you might get what I’m trying to understand here. If ketones are spared for the brain and muscles primarily use FFA as fuel after keto adaptation, then why would ketone supplementation help physical performance?

    • Not necessarily. Muscles also use ketones–perhaps some more than others (e.g., heart probably uses more than skeletal; not sure about smooth).

  • Alex

    I agree that appetite regulation is an important topic. Experienced myself that just after one week low-carb I had less appetite. This in itself might be a reason why low-carb is so successful. I guess it is natural for the body to indicate that ‘you are doing fine, no need to eat’, but this needs to be scientifically proven, ie as mentioned in one of your video talks a good cocaine addiction also makes you less hungry and lose wait.

  • Aaron

    Hi Peter,

    Since ketones are generated from the breakdown of fatty acids, it makes sense that there is a linear relationship between BHB levels and fatty acid oxidation. Have you found this to be the case empirically?

    Thanks, Aaron

    • It’s hard to measure fat ox without special equipment.

  • thanks for the detailed post peter. we are getting ready to introduce a powdered bhb salt (calcium and sodium combo) that is flavored, pH adjusted, and quite palatable. just mix with water.

    • Great to hear, Patrick. Can’t wait to try them. I love what jet fuel does…just don’t love the taste.

  • Aaron

    In terms of your RQ, does fat utilization go up linearly with BHB level?

  • Hi Peter, fantastic article! Can I help you answer some of the open questions? I recently quit my day job as a software engineer at a hedge fund to start a new practice with a medical doctor. We’re both elite level mountain bikers. Ketosis has improved my life in ways I never could have anticipated and I’m really keen to further the research. I met Dominic at AHS and will be interviewing him for our podcast in couple of weeks, can you put me in touch with anyone in California with the equipment and knowhow?

  • Dan Walker

    Have you come across a decently accurate way of measuring an individuals insulin response to artificial sweeteners since this is being talked about as a possibility? I keep wondering if C peptide could be used for this or if an actual immunoassay would be required, or if you could even get an actionable number from an antecubital blood draw for something like this. If you try and ascertain this with diet and a glucose/ketone meter it just seems like it would (or could) potentially take a while (days or weeks) to get anywhere near an accurate picture of one’s response.
    I am definitely going to try some of Patrick A’s BHB salts. Have you tried chilling any of the esters as cold as possible before consuming them? That might help although from what you describe it sounds like it might take a miracle flavoring agent to get them gag proof and I drink Laphroaig from time to time, which to me always seems to have this quality of a Betadine soaked bandage to it, but that’s just me 🙂

    I may have to look up Dom one day as I am always over at Moffitt or M2Gen working on a robot or 2 of theirs.

    As always a big thanks for your efforts and time.

    It is much appreciated!


    • Better tasting agents are on the way. I think the AcAc di-ester and the BHB salts are the way forward. I see no advantage to the BHB mono-ester.
      To your first question, I’d suck it up and do the RIA to find out for sure.

  • Yeah. I just hate to add to the RIA workload of some poor bench tech out there although I suppose in this day and time they may have a fluorescence based version of the assay. I know what a huge PIA radioimmunoassay’s can be. When I first got out of university I got a bench tech job working for LabCorp’s Center for Molecular Biology and Pathology doing an RIA for unconjugated estriol in the Biochemical Genetics Lab. They used the Foundation for Blood Research’s algorithm for risk screening for pregnancies for Trisomy 18, 21 and open neural tube defects. Ue3 was a critical analyte for the algorithm. Our assay used I-123 and I did anywhere from 700 to 1000 patient samples every evening. Using giant centrifuges with these custom rotors to spin down huge racks of vials. Dealing with (potentially) radioactive water baths and this huge ancient automated scintillation counter that was always getting jammed. Then we had to hand transcribe all the results. Eventually I ended up performing radioactive PCR for Fragile X Syndrome in the Molecular Genetics/Molecular Oncology/Pharmacogenomics department before I matriculated into lab management although I was still radiation safety officer even when I was managing the lab. Used to log in 32P and 35S Methionine every week and dealt with all the decay and disposal. So after all that I just have this aversion to radioactive anything with an aversion to lab management in close second place. Now I I’m just a lab automation jock for Qiagen driving all around my good ‘ol home state of Florida trying to find a way out of this NIDDM maze I have gotten myself into. You and many of your colleagues have been a tremendous help with showing me the way when most of the health care professionals I have been to just want to pump me full of what I consider to be subpar options on the good end and just outright dangerous on the bad end, like Byetta. I only have 1 kidney because of an undiscovered elongated left ureter that kinked up and caused primary hydronephrosis that had destroyed the kidney on that side by the time the repair was initiated. The removal had to be done through the vertical incision (lumbotomy?) through which the repair of the ureter was supposed to be facilitated. As a surgeon I’m sure you can imagine how these guys ended up getting through that. Took forever from what I was told. Anyway, I want to try a low dose of Metformin but there is always this looming lactic acidosis issue so I need to find somebody that is willing to work with me although the last time I saw my nephrologist he said I had the highest eGFR he had ever seen especially for someone with one kidney. He was walking around showing the result to all of his residents over at USF. I am also wondering if I can get some decent suppression of liver GNG, possibly on par with Metformin, from the BHB salts. Only one way to find out I guess. On with my N of 1. We should all get T-shirts made or something 🙂

    Thanks again for all the inspiration!

  • Dr Attia

    Phenomenal post as usual. The slow drip of information that your blog provides is worth its weight in gold. I’m currently in ketosis and plan on utilizing the body by science routine. I was initially thinking of taking something like ucan before my exercises in order to prevent bonking. I realize this is preliminary, but do you think exogenous ketones can be used in place of ucan to prevent bonking.

    • Emphasis on the “slow drip” part…
      I have not combined UCAN with XK, but I think it could be an interesting combo.

  • Santiago

    Peter, your nearly-obsessive level of detail and experimentation is what makes eating academy unique. I devour every article and I thank you for making me smarter.

    You made me change my diet (along with Taubes), and I really hope your studies results at NuSi change the world of nutrition forever.

    Now that I’m done inflating your ego, I wanted to know if you heard about KetoForce. It’s a product made up of BHB salts http://prototypenutrition.com/ketoforce.html so in theory it would work exactly like the esters, no?

    My only worry is that excess exogenous ketones could cause acidosis, and hypoglicemic shock…since the body stops ketone production by secreting insulin, maybe taking too many ketones can do that when the body secretes more insulin to maintain equilibrium, perhaps sugar would be beneficial to at least maintain blood glucose?

    How much is too much when taking exogenous ketones?

    • Yes, ketoforce is a BHB salt prep (I don’t recall which salt this is). In theory they should work like the ester, but I’m not sure that is entirely the case. They certainly taste better.
      I’m sure one can take too much, but I don’t think such levels have been established.

  • SL

    Dr. Attia,

    Thank you for what you do. I have sort of awoken to my dire situation and have found your blog helpful. My numbers from 2 weeks ago are horrible:
    LDL-P number 1900
    Small LDL-P 1600
    HDL-C 32
    LDL-C 110

    From what I have read, I am a ticking time bomb. Argh it sucks. I have a very young daughter and I am only 34 (6.1″ and 195 pounds). I am trying to now go on the no carb kind of diet but just worry if it is too late.
    Btw, I live in San Diego. But I think you do not actively practice since I could not find your information anywhere. I will probably go see Dr. Triffon.

    • pone

      Those LDL-P are not as terrible as you think. But plenty of room to improve.

      Study fatty acid compositions and you will see that there are four specific types of saturated fat, and different foods have these in different compositions. What I found by experiment is that my N=1 is that only certain types of saturated fat elevate my LDL-P. For some reason dairy cream makes my LDL explode. I went up to LDL-P of 2300. To contrast, coconut milk, animal fat, and moderate indian ghee I seem to tolerate. Just by excluding the dairy fats in cream I got my LDL-P to 1600 and it is still coming down. Once you understand relative fatty acid compositions of the fats you eat, you can start to do targeted experiments and repeat the NMR lipoprofile periodically to see which fats most affect your numbers either way.

  • Lance

    Don’t know how these work, but it seems like the rate of available ATP could be higher and last longer than ketones, aerobic, anaerobic, phosphorus. If true it could help in everything from reaction times to burst events/sports? Which would bring into being a whole new modality of training. Seriously? Say it ain’t true!

  • Got my September issue of Wired in the mail yesterday. Great article Peter.

    • Thanks, Dan. My daughter asked why she couldn’t be in it holding a spoon.

    • Tim C

      The beard looks good, too.

  • Magnus

    Totally OT, but I read your old post on Do calories matter? (Feb-March 2012):

    You seem to have got it backwards when you speak of breaking [chemical] bonds as a way of “releasing energy”.
    Its the other way around: Bonds are “valleys”; you need [external] energy to get out of them. You release energy when bonds are formed (“electrons rolling into valleys”).

    Otherwise a very interesting site?

    • Magnus

      Otherwise, a very interesting site!
      Exclamation, not question!

  • Daniel

    Hi Peter, fascinating stuff and considering buying KetoForce exogenous BHBO product. In your knowledge, has there been any research on the effectiveness of exogenous ketones when combined with elevated insulin? Obviously ketones wouldn’t be produced by the liver under these conditions, but is there any research proving how exogenous ketones might act in these situations?


  • SL

    With the wealth of knowledge you are accumulating, Dr. Attia, I think you should do a startup on customized nutrition plans :-). People will send their Lipid profile history and details (you could even hookup with 23andme) and you and your team create a custom nutrition plan. You could even do enterprise pricing 🙂 .

    I am spending too much time on your website :-/

  • Kathy

    Hi Peter,

    I was trying to find some information on your site with regard to flow-mediated dilation of the brachial artery. I was reading several journal articles on ketogenic diets and came across this meta-analysis:


    It sounds like the low-carb diets results in greater cardiovascular risk when using the FMD but it’s unclear to me why this might be and whether this would hold true if I tried to maintain ketosis through soy, fish, eggs, and nuts but no land or air animals. Any thoughts or can you point me to good follow-up reading?

    • It’s unclear to me if this artificial test of the radial artery has any clinical significance.

  • Mario Pineda

    I find your blog really interesting and was considering making a PDF with all its entries so that I can read it more easily. There’s something else I want to do with that PDF that might be problematic: I have several medicine students among my friends and I was considering printing and distributing it among them to try and make them understand that there might be one or two things wrong about the approach their professors take. So, is the content of this blog available for public reproduction and distribution?

    Thanks a lot for your knowledge and for sharing it with us!

    • Sure, if you reference it appropriately, please pass around as you see fit.

  • Jason Luchtefeld, DMD


    First, thanks for sharing so much.
    Second, over the last several months I have been suggesting a low carb diet to patients (mainly to help reduce cavity risk). It would be advantageous to have resources to suggest to them. Currently, I give them (or suggest they buy) Volek/Phinney’s Low Carb Living book. Any other suggestions?

    Third, as products come into the market in the supplement world. Do you have a suggestion on how we can determine the quality and contents of any products? The concern, obviously, being the stated ingredients are only partly true/accurate.

    Finally, excited to see what NUSI does in the nutrition world.

    keep it up!

    • I don’t really follow the books in the space. I don’t know the answer to your last question. Because I know a very good compounding pharmacist, I run any supplement I try by him first. I think there are folks out there trying to put info together on supplements, more broadly.

  • Stephen

    Wow, your fat oxidation rate of 1.2g/min still is pretty darn high, given that the average person is about 0.5g/min, and even professional (high carb?) racers are around 1g/min. What range of numbers do Pat and Dominick see in their clients? (Do they see the “standard” < 1.2g/min for high-carb athletes?)

    So having a 0.5g/min FOR advantage will provide you with 270 kCal/hr additional fuel "without eating". Pretty interesting. Thanks for sharing your data.

    BTW, there's a scatter plot of VO2max vs. FOR, showing a fairly linear correlation, over data points including untrained subjects as well as professional cyclists:

    • I can’t speak for them, but Pat has tested me at much higher levels when we push through to VO2 max. Jeff Volek has seen the gamit of fatOx rates. LIke I said in the post, I think there are folks out there who can get to 2 g/min, though I doubt I can get above 1.7 g/min.

  • Mary

    I have followed a ketogenic diet on and off for a few years. As a long distance runner, I do find that the ketone adapted state yields greater muscular endurance (my own experience) and helped me with a marathon I ran in the Himalayas. I placed 2nd out of the females who were foreign (I train at sea level) and 6th out of all females.

    I have recently learned, however, that my son has a disorder of ketone metabolism. We have followed low carb style eating for years and my son has truly struggled. After a great deal of testing leading absolutely no where, we finally decided that he has an IEM and had arrangements with the local hospital to do the right tests during an episode (encephalopathy, vomiting, etc). What we learned is that he produces very high levels of BHB and AcAc and was experiencing metabolic acidosis with a high anion gap. He also produced respiratory chain metabolites in his urine. The doctors have narrowed it down to Beta keto thialase deficiency, SCOT deficiency, or SCADD. So far the tests are inconclusive. For BKT and SCOT, they are enzymes needed to break ketones down into usable form in order to go through the citric acid cycle. I am not a biochemist so I might be wrong about the details. (Economist here!)

    Thanks to my years of keto-running, I now test my son for BHB and blood glucose and use the keto sticks to test the AcAc. We are now catching the episodes earlier because we know what to look for and can test for it easily. While he continues to have episode of keto/metabolic acidosis, they are less severe than his first episode.

    In the intervening months, I have begun studying the different energy pathways to try and understand what is happening to my son. I am curious about your perspective on these abnormal metabolic issues and ways to work around them.

    Thank you so much for all your research. I have thoroughly enjoyed reading your blog for years.

    • pone

      Have you tested your son’s VO2Max? In metabolic disorders where the aerobic capacity is not limited by oxygen, but by efficiency of the electron transport chain, a low VO2Max might help you to very cheaply quantify how well his mitochondria are working.

      I have some extreme mitochondrial injury, which has taken me the better part of 14 months to chase down. It was not until I did VO2Max, and objectively quantified that I had changed from endurance trained to aerobic metabolism that was worst data point in a 200-person study, that I realized the extent of the injury. VO2Max might help you to add another data point to your son’s condition to help characterize it.

  • Jonathan Mylrea

    Hi Peter, this is probably well off topic, but I am interested in your view. A friend, who is a type 1 diabetic, and I have been following a ketogenic diet for a few years now. We both do trail running and have seen big improvements in our performance. Incidentally, his insulin consumption has dropped from around 25 units per day to around 5. In the past, when he has mismanaged his insulin or sugar intake, and become hypoglycemic, he has become disorientated and, sometimes, almost semi conscious. More recently when he has stopped and tested his blood sugar during a run, he has discovered it to be extremely low, for instance 1,4 mmol/L and yet he is quite focused and calmly consumes some sugar to bring it back up. I am sure that, before he was on a ketogenic diet, he would have been incoherent at this blood sugar level. Is it possible that, since his brain is being fuelled by ketones, it is less susceptible to hypoglycemia? This may be of great benefit to type 1 diabetics if true.

    • I think that is exactly what is going on.

    • Joanne

      Along this line, I’ve wondered about the effects of the insulin production caused by proteins as per the Insulin Index (II). If one is on a ketogenic diet, one is, and is aiming for around 20 grams a day of CHO, one should already have low blood sugar. Then, if one were to eat beef or whey one would get a dose of insulin without the signal of rising blood sugar, since beef or whey do not raise the blood sugar but cause insulin secretion anywhey. Golly, I thought, wouldn’t that cause hypoglycemia big time by pushing down an already very low blood sugar, a dietary situation I’m likely to be in several times a day. I’m goofy by nature, so the disorientation symptom of hypoglycemia might not be so noticeable, still, I don’t think I’d miss it entirely if it were happening that often. So the idea of keytones feeding the brain, and most tissues, would explain the absence of hypoglycemia on a ketogenic diet when high II foods generate insulin production into a low blood sugar situation. Or am I missing something?

    • Joanne

      Rewrite of penultimate sentence: So the idea of keytones feeding the brain, and most tissues, would explain the absence of hypoglycemia [symtoms] on a ketogenic diet when high II [proteins] generate insulin production into a low blood sugar situation. Or am I missing something?

    • JB

      Robb Wolf describes an experience of imitating a paleo-era hunt, which was physically taxing. He was mildly keto-adapted when doing it. Afterward, his blood glucose was measured and it was incredibly low – IIRC, somewhere in the 40 mg/dL range – but he was fine. The belief is that his brain was using ketones.

  • Mark

    I’ve been in ketosis for about a month now and I test my blood ketone levels first thing in the AM. Today’s reading was 3.4 mM…is that too high? I’ve read all the books and they mention that 3.5 mM is the upper end of a therapeutic level and above 3.5 is known as “starvation ketosis”. I’m going to adjust my protein from 70 grams to 90 grams and see what happens. Any insight would be appreciated.

    • Mike Nunan

      Hi Mark,

      If it helps, I’ve had BHB levels of over 5.0mM/l without any ill effects at all. Acidosis happens at considerably higher levels than that (I faintly recall seeing a threshold in the double figures being quoted somewhere but please do check if you want to know for sure). In a healthy and non-diabetic person ketone body production will be down-regulated well before such levels are reached.

      Best regards,


  • Jan

    Hi Peter,
    might I know your opinion on whether ketosis affects in any way a bone fracture healing? I read somewhere that acidic environment is not ideal for bone healing.
    Thanks a lot.
    PS: wonderful web of yours, thanks for it.

  • Drew M

    I had two relatively straight forward questions that should be mildly interesting-

    1. For some unknown reason, I have started to think that artificial sweeteners are at least the smallest bit responsible for insulin insensitivity. That is, perhaps the taste of “sweet” is *somehow* relayed from the tongue to brain/intestines(just guessing here?) to the pancreas, causing insulin to be released. Of course, the taste is artificial and there is no sugar and therefore, the body starts to ignore changes in insulin levels independent of blood sugar.
    Of course, I could totally be wrong about this. Any thoughts?

    2. If someone on the ketogenic diet strictly limits their sugars, and bacteria in the mouth prefer digesting sugars (I am not sure of this assumption), then wouldn’t the ketogenic diet support teeth/gum health?


    • Gisela

      @Drew M

      I don’t know about question #1, but the answer to question #2 is a resounding YES! I used to have gingivitis, but since going low carb, and eventually to nutritional ketosis, my gums have healed up and I never wake up with “fuzzy teeth” anymore. No more cavities either. This appears to be a common and pleasant surprise bonus to folks who reduce their carb consumption for other reasons, such as weight loss or diabetes management.

      Keep on smiling!

  • Jonathan

    Hi Peter,

    Great post and great self-experiment. It looks like you’re done a couple of posts now regarding exercise/energy and ketosis. I was wondering if you know of any good resources about the effect of nutritional ketosis on muscle growth (or atrophy). I’ve found some literature online but it’s a bit lacking in the science department.

    • Jeff Volek and Lyle McDonald are worth reading on this topic.

  • Perry

    Re insulin index, look at Mark’s comments:


  • Mike


    Three weeks on high fat, low carb average less than 50g Carbs, 110g protein and > 200g fat per day.

    NMR lipoprofile

    LDL-p 1470
    LDL-C 115
    HDL-C 58
    TG 66
    Chol. total 186

    HDL-p 36.4

    Small LDL–P 672

    LP-IR score 46

    46 year old male. 6 foot, 195 pounds. Weigth lifting. Family history unknown-adopted

    Any interpretation greatly appreciated. Thanks for all your insights and work!


  • Pingback: 866: Ben Greenfield — KETO CLARITY Expert Interview | The Livin La Vida Low-Carb Show()

  • Mario Pineda

    Hi Peter!

    I just came across this link and reminded me of your comments about how different types (like your wife and you) react differently to carbs. Thought you might want to check it out:


    • John U

      Mario, I checked out the site you referenced and I noticed it does not entertain comments. This site looks like a “for profit” site. Personally, I don’t trust sites which do not accept commentary. Commentary keeps you honest and credible. I learn a lot from comments. So my impression of what this site presents is biased from the start. For me, a no-biochemistry engineer, the content may be correct, but I would not give it much credibity.

  • Avner Taieb

    Hi Peter,
    Thanks for investing the time to write a very interesting post again. What is the possible explanation for the resting state’s RQ to be higher then in the workout. I was sure that the higher the intensity the higher the RQ. Specifically in the control test.


    • O2 consumption goes down more than CO2 production does.

  • Avner Taieb


  • Herb


    DENNIS BANKS – RIDERS AND SUPPORT PEOPLE — This Katie Couric Documentary — Sugar and Diabetes and Obesity Epidemic — Came out just days ago and has 120 feedback already. — You guys are doing great! Keep up the great work! — People just don’t know and aren’t able to grasp and understand the reality and truth in this. There should be five thousand feed back already. The world just doesn’t know. There genuinely may not be a seventh generation with enough health to do anything to take the land back if this epidemic is not stopped in it’s tracks. It is preventable with diet and exercise. Dennis is a perfect example. Dr. Jay Wortman “My Big Fat Diet” Documentary is another example. — After this war is won DECLARING WAR ON INDIAN CASINO’s AND GAMING, CLOSING ALL FIVE HUNDRED CASINO’S ON THE RESERVATIONS, needs to be next. These Casino’s are ten times worse than Diabetes. There will be no more Indians unless they are stopped and closed. Assimilation/Quantum Reductions so that they will have more “white” people to work at the Casino’s, like Las Vegas and Reno and Tahoe and Atlantic City. More money for the white man power brokers who are supplying everything for the Casino’s, five hundred Casino’s strong and growing. Five hundred cash cows. Hundreds of millions of dollars annually, “Billions of Dollars”. — Many leaders and Chiefs are taken in and fooled by all that money. “Blinded by the light”. — ” Blinded by the glitter of all that “gold”. — Thank for your time and looking at and reading this, miguich, or however you say it, thanks again, Tom Bunnell, a 100% White Man, 69 years old, from Detroit Lakes, Minnesota — White Earth — My grandfather moved onto the reservation 1935 — I would like to live to see the day “my” seventh generation, of white people “all” move off from the reservation. The people paid for their land and farms and resorts by the US Government and a few generations allowed to stay for awhile as the transformations take place with all land transactions going back to the tribes. It’s a wonderful place to live and I wish we white people could have such a beautiful piece of land even though it is a pittance of what you had and should have.

  • Isaac


    I wonder whether you know or have in mind doing some other types of experiments relating to cognitive self-control. You have mentioned before that keto-adapted people seems “to work continuously” and don’t lose focus (it happens to me). I wonder whether one could design some experiments along the lines of


    to see whether giving exogenous ketones will improve attention in cognitive tasks.

    • Yes, I’d love to see such an experiment done well.

  • Ian Beveridge

    Hi Peter,
    I recently saw you on video stating that your chosen food while training was carbohydrates – either by eating cashew nuts for slow release or “superstarch”. Would your results here change that choice in any way? I personally am considering using dried coconut meat instead of cashews due to the very high MCT oil content and the similar overall carb content – just a little lower than cashews.

    Last weekend I was in a hill climbing (14km long and 1km vertical ) bicycle race and as I appear to be properly keto-adapted decided to attempt it in this state – with no additional carbs. The race took me 58 mins 53secs and my average heart rate was 95.4% of maximum over this period. My only addition was to supplement ketones about an hour before the start – from coconut oil. Only one one single occasion – 5 years ago at age 50 was I able to go under this time and match this heart rate – but I was using carbs. On that occasion I was noticeably breathing much more heavily and had a post exercise asthma attack immediately on stopping after crossing the finish line due to hyperventilation (the body eliminating CO2 to keep blood acid in balance). On this recent occasion – without carbs – there was no asthma attack. Mentally and physically I felt less stressed altogether and was totally surprised to be able to sustain such a high output level under ketosis.

    I should add that my overall strength is relatively low at the moment due to having lost 28.5lb in weight over the last few months – due to both fasting and a ketogenic diet. Strength building will be on the cards soon instead of weight loss and I’m confident that next year the 90 second gap to my 5 year old record will be broken.

  • Elle

    Don’t know where to post this but can you comment on this recent finding that artificial sweeteners have been shown to alter gut bacteria and create glucose intolerance?


  • Myddy

    Hi Peter,

    Any quick comments on the new Nature study regarding artificial sweeteners? Have the results surprised you at all – particularly the 3rd part of the study (despite being very preliminary)?

    • The mouse data are useless. Who cares what happens in a mouse. Not the species of interest. The experiment that needs to be done is as follows:

      2 groups eat the exact same food for 2 months Group 1: drinks 3 soda waters per day; Group 2: drinks 3 diet sodas per day

      Both groups consume the same # of calories, type of calories, etc. and even same amount of fluid and carbonation.
      Measure glucose disposal and other tests of insulin resistance pre- and post.

      Easy study…hope it gets done. Until it does, I’m not convinced that diet soda is harmful, but it’s a very interesting question and it needs resolution.

  • Leo

    Hi, Peter,

    I have read Volek and Phinney, have followed Ben Greenfield, and a bit of the IF pioneers, and wonder how you would weigh in on low carb and thyroid issues? and, for that matter, higher cortisol levels in endurance athletes? I remember reading Ben Greenfield saying that you could potentially f**k up your thyroid doing low-carb and endurance training. And, despite doing all of what he suggests to curtail potential damage, how would I know if my thyroid was having issues?

    I am a month in on a ketogenic diet and have had blood lipid tests (all of which have come back well within super-healthy) but I am having a hard time getting above 1.0 mM for blood ketones. I have just reached the peak of my training cycle (60-75 miles a week of running) and am beginning tapering for a 50K and for the most part, feel fine. And, worth noting, during the last month, I have at most used two servings of UCAN and Vespa in my 20-27 mile runs. I’m always surprised by how NOT hungry I am afterwards compared to when I was a carb-loader. However, I feel like I may not be reaping the full rewards/advantages of being in NK if I can’t push into the higher blood ketone levels.

    Any pointers would be appreciated. And, this blog of yours is an absolute gold mine for any athlete dabbling in self experimentation to improve performance!


    • My thoughts and now my clinical experience on this topic are so complex that they warrant an entire blog post, rather than a quick response (at the risk of “pulling a Fermat”). But I don’t want to promise anything. Blogging is currently priority #11 on a list of 10 things in my life.

    • Hemming

      http://caloriesproper.com/ketoadaptation-and-physiological-insulin-resistance/ . Many people experience a drop in ketones after the intial adaption period. I think its important to consider if more ketones equal more performance, health etc. if you’re already doing good.

  • Jack

    Hi Peter,

    I remember someone asking you about what is your target market and your answer was, “I do not have one”. I think that you do have a “specific” target market, which are people who are not happy with the standard diet and they are looking for an alternative diet.

    The reason I mentioned this is because I have discussed this with others and look at me like I have two heads. I have discussed it with a few doctors and some intelligent people (who are suppose to be open minded) and still, I get this crazy, you are dying from the inside look. And it is very, very difficult to even get some of these people to read the research or at least read about the subject. Your target market is a few step ahead from most people (maybe some are just jumping from diet to diets, but I would like to say most of your followers like the scientific research behind your information).

    That out of the way….

    All my life I have been checking my cholesterol (standard) and that’s what I have been going by. My doctor of course also recommends that (I do not have any cardiac conditions, but I like to know where I stand. I am 28). I started reading about nutrition about 7 months ago. I started reading about the people who disagree with the standard american diet and see what their reasons were. I started with the dietdoctor.com and from there I jumped on your blog and some other blogs as well. I like your blog because you are all about the numbers (which I think most of your followers like that about you).

    I have an autoimmune disease (plaque psoriasis). I dropped eating grains 7 months ago and I lost about 20 pounds (in a 2 month period). My psoriasis is not as itchy but still there, still red. There is something else that is going on… I have read a few “autoimmune protocol” and have experimented (dropped all dairy) nothing. Now I read on thepaleomom.com which is the “Autoimmune Protocol”. Im a give it a try for 3 months or so and see if any changes happen. (Thought i’d tell you a little of my back story).

    I have been reading about which tests to do (directlabs.com there is a never ending list). I like to know if what I am doing is helping or not, then modify it. I have been searching around how accurate these tests are, some say they are accurate and some say they are not (who to believe…).

    All my life I thought the standard cholesterol was “it”. Predicting cardiac diseases. I do not have a medical background. The only knowledge I have gained is from reading your blog and others. Before this I was eating a “balanced” diet, spread your food throughout the day, UNINFORMED.

    I never knew about NMR until I read it on your cholesterol series. And my doctor never recommended (I guess I am getting another doctor). I am a business person and my time and knowledge is business (human behavior as well, but that is more of a hobby). I do not have the time to read all of these theories about nutrition. Before I would ASSUME that the information out there was the BEST to the knowledge and tools we have in this society, which I was wrong…. So now I have to put the time myself to read all of the information that is out there and then make a decision of what/how I should eat among other things.

    I noticed on your “coming soon” list there is a “What tests to get done if you want to track your health”. I think many people would benefit on your opinion of which tests to take. This way, they can track their health and modify it by their body’s reaction (which differs from person to person). I understand your schedule is extremely busy, but thought I’d share my input.

    Thank you for what you are doing again.
    (This was a quick ramble so dont mind structure of the paragraphs and the the grammatical errors)

  • Samantha

    Hi Peter,

    Thank you for this great post and experiment, I hope it can be continued in a more intense research setting. Do you see any use for compound-specific isotope analyses in determining the actual source of material being utilized–for example, I am guessing that ketones that are burned from fat would have a different d13C than exogenous ketones, and you can even have an isotopic tracer attached to the exogenous ketones, so that you can isolate the CO2 released from respiration and determine the % of C from exogenous vs. endogenous ketones.

    I have not yet gone through all of the comments so I don’t know if this has already been addressed, but can there be any detrimental side effects of having this amount of ketones?

    I am at present in deep ketosis and training for mountain bike endurance racing. I raced my first 24 hour race very low carb and it went extremely well except for the terrible sinus headache I got from the weather/allergies. But, I didn’t have to eat much and I never bonked. If only I didn’t love pizza so much…

  • JJ Bell


    Realised I have not commented on this post to date (the shame) as I have little to add but am continually fascinated with your n=1 adventures.

    Wish to echo comments of others in that we really appreciate (& value) the time you devote to this, as nothing compares (that I have found). Your endless jet fuelled energy and GRIT are no doubt how you manage to accomplish so much.

    As a parting note, let me add, the fact that you have no target audience is one of the things I (and probably others) like about you (or your blog) the most. It seems many want a chunk of your inquisitive mind (& time) but we are more than happy to settle for whatever crumbs you can spare.

    Quality, not quantity.

    • Thank you, JJ. With that freedom I may start writing about even more of my far out obsessions…

  • Hakim Hakim

    There’s this show on Cinemax out now called The Knick. It shows us the life of early 1900 medicine and how medicine was still primitive with experiment procedures and people dying on the operating table normally, yet the doctors still fought the good fight. It’s really interesting.

    Medicine and technology have advanced exponentially and while there’s always something new to learn, we’ve made large strides.

    I was just thinking today how the field of nutrition is kinda in its primitive stages similar to how medicine is depicted on that show, figuratively speaking of course. Medicine has made those strides and nutrition still has yet to take major strides relative to medicine. If people really see the importance in it, as yourself, then maybe the field can grow.

    What your doing with your organization should have been attempted 30 years ago. But it’s fine, we have technology now.

  • Hakim

    Fine. Here’s a better one.

    Lebron James and Ray Allen adopt low carb. They site Volek. Things like this can help.

  • amita


    Your emotional stretch in your TED presentation was inspirational. You model humility combined with the best forms of curiosity for those who care about health.

    Might you comment upon breastfeeding versus manufactured “infant formula” as you may understand such from the dietary perspectives, such as ketonemia, you recognize and discuss for older folk?

    Your leadership is desired!

    Thank you for moving with your focus and your work!


    • Well, this is a topic near and dear to my heart as we have a 3 week old baby at home! I’m not an expert on this, and a lot of the data I’ve seen are weak. While I realize there are many circumstances that prevent women from being able to breastfeed it seems that doing so, especially early on, trumps formula. In addition to the benefits of BF (e.g., passive immunity), there are downsides to formula, namely the ingredients. On my to-do list is to find infant formula (I’m sure our little guy will need it eventually) that doesn’t contain crap.

    • Yossi Mandel

      Congratulations! We discovered neocate after many bad episodes with other formulas.

    • Kelley

      I thought I caught the phrase “my kids” (plural) in one of your posts. Congratulations on your new little guy! Wonderful news. PS Anecdote alert: I’ve also heard good things about neocate from a friend of mine who had trouble breastfeeding. For a funny, wise perspective on women who have challenges breastfeeding and the folks who judge them, read the relevant chapter in Bossypants, by Tina Fey.

      • Thank you, Kelley. The little guy is pretty cool. We’ve given him a great middle name, too.

  • Pam

    Congratulations to the Attias!

  • Norm

    Many congratulations on the new Addition to the family Peter! Wish you a happy and lessed family life .

  • Norm

    Sorry, happy and BLESSED family life.

  • Ellen Urciola

    Yes, Peter, Congratulations, health, happiness, and contentment to your entire family! Thanks for sharing with us!

  • Carol

    Don’t assume your baby will need formula. It’s possible to utilize a little hormone hack that will reduce the amount of time spent pumping. Contact me if you are interested.

  • Daniel

    Hi Peter,

    I didn’t know where to post this but was interested in your opinion given your experience. I just started a very low carb diet two weeks ago and my ketones raised to 0.5mmol/L today so officially ketoadapted I guess. I’ve done some mild intermiitent running with walking. I had my blood tests done a couple of days ago and the doctor said he could count on his hands how many times he gets blood tests that good. But what was the most interesting is it seems to have eliminated symptoms of my Thalassemia. As you probably know Thalassemia means I don’t bind iron very well, and I have never been able to give blood due to having such a low iron count. Here are my blood tests – http://saturatedinfats.com/2014/09/27/ketogenic-diet-has-eliminated-thalassemia/

    The iron part is at the bottom. Do you have any idea as to why this might happen on a low carb diet?

    • Darkbloom

      Hi Daniel,

      after two weeks you are probably not keto adapted but merely in ketosis – keto adaptation will usually only occur after 3+ weeks of constant ketosis and is characterised by your energy levels recovering to pre-ketosis levels, which is most likely due to mitochondrial ramp-up. check here; http://caloriesproper.com/ketoadaptation


    • Rob Coberly

      See an example paper below re a thalassemia strategy that I think applies in this situation. Butyric acid was an early agent of investigation into epigenetic effects of histone deacetylase inhibition. Butyrate circulates in small amounts normally, absorbed from microbial production in the distal gut. Beta-hydroxybutyrate, the ketone body, is a related molecule, and also an effective histone deacetylase inhibitor. See the very informative papers by Eric Verdin and JC Newman on this topic. HDAC inhibition permits transcriptional activity at the acetyated gene promotion sites. The idea is, you still have a silenced fetal globin gene, and if an agent can promote restoration of transcription of that, the beta-thalassemia may benefit. The HDAC activity of BHB was shown to promote a number of stress-response and antioxidant genes (catalase, superoxide dismutase, and others) and the full spectrum of genes promoted by this mechanism is not yet known. I suspect by increasing your circulating BHB you may be activating the transcription of fetal globin protein.
      About a year ago, a U. of Oxford ketone body researcher shared with me that their group was seeking a grant for study of BHB in sickle cell anemia. That would possibly be the same strategy.

      Rob Coberly

      1. Experientia. 1993 Feb 15;49(2):133-7.
      Butyrate-induced reactivation of the fetal globin genes: a molecular treatment
      for the beta-hemoglobinopathies. Perrine SP(1), Faller DV.
      **emphasis added below**
      The inherited beta-hemoglobinopathies (sickle cell disease and beta thalassemia)
      are the result of a mutation in the adult (beta) globin gene. The fetal globin
      chain, encoded by the gamma globin genes, can substitute for the mutated or
      defective beta globin chain, but expression of the gamma globin gene is
      developmentally inactivated prior to birth. Re-inducing expression of the normal
      fetal globin genes is a preferred method of ameliorating sickle cell disease and
      the beta thalassemias. Stimulation of as little as 4-8% fetal globin synthesis in
      the bone marrow can produce > 20% fetal hemoglobin in the peripheral circulation,
      due to enhanced survival of red blood cells containing both sickle and fetal
      hemoglobin, compared to those containing sickle hemoglobin alone. **Butyric acid
      and butyrate derivatives are generally safe compounds which induce fetal
      hemoglobin production by stimulating the promoter of the fetal globin genes.**An
      initial trial with the parent compound, delivered as Arginine Butyrate, has
      demonstrated rapid stimulation of fetal globin expression to levels that have
      been shown to ameliorate these conditions. Phase 1 trials of an oral butyrate
      derivative with a long plasma half-life have just begun. These agents now provide
      a specific new approach for ameliorating these classic molecular disorders and
      merit further investigation in larger patient populations.
      PMID: 7680003 [PubMed – indexed for MEDLINE]

  • Herb

    He won’t need “formula eventually” if you and your wife simply refuse to get involved in anything that would stop or hinder your wife from breastfeeding every moment of every day until your child weans himself or another baby comes along and takes his place. Our families and wives and children are everything there is in life. Totally 100%. A glorious and wonderful existence when we live it together 24/7 365 like nature intended. Always and forever. A gift to all who are smart enough to not let this be taken away from them.

  • Hi Peter,

    I assume you have your reasons for not specifically answering my previous question about what supplements you would now choose to use during training session – given the effect of exogenous ketone (or more accurately MCT) supply.

    I have a few observations to add. Bear in mind that I am supplementing both ketones and carbs in low quantities when training or racing.

    Observation 1 – You appear to be correct in that any carbs consumed during an event – at least when consumed a few hours into the event – do not impact ketosis. You describe this as being due to a “carb debt”. (I have measured approx 1.7 mmol/L before a competition and 3.4 mmol/L after despite eating carbs) Reading about the Ranulph Feinnes/ Mike Stroud 1992/3 expedition to be the first ever to walk unaided across the Antarctic however raises a question mark over the “carb-debt” idea. The two adventurers – in a bid to reduce their carrying weight ended up with a high concentration of fat for their food – which I calculate to have provided 75% of their calories. They were burning over 11,000 Kcal per day – every day for 6 weeks – measured using radio isotopes. They took blood samples every few days. By the end of their trip their blood glucose levels were so low they would normally have been dead at 0.2 mmol/L. When the readings were analysed the medical experts initially thought they were simply in error – but they were not.

    My point is this: What is a “Carb-debt” when the body can apparently normalise to 0.2 mmol/L? Would it not be better to aim for this than feed a system (with carbs) that assumes 4 mmol/L minimum is “normal” and necessary?

    Observation 2 – During cycling competition I can maintain an anaerobic level for over 4 hours with much of this apparently “red-lining”. So if I’m now not actually burning carbs and burning ketones instead then is this actually correct to call this “anaerobic” in the sense of being 70% carb burning – which it now clearly is not?

    Observation 3 – At almost exactly 4 hours and 30 minutes into an event – no matter what I’ve been doing in terms of effort up to this point – there is an effect like a switch being thrown that brings a strong resurgence of energy. This doesn’t affect heart rate but it allows much more power to be accessed without a raise in average heart rate. So far once this has started it remains constant until the termination of the event – from two to three hours later. I have absolutely no idea why this happens – but I can almost set my watch by it because the timing is so precise.

  • Greer

    I’m in an introductory biology class and we are learning about glycolysis, gluconeogenesis, and what happens to the food you eat. However, no mention of ketosis. Wish there was something about fat metabolism in my textbook.


    p.s. Peter, you are my idol! I am majoring in biochemistry, and I think my interest is inspired by this blog.

    • Hmmm, keep looking, it’s got to be in there somewhere! Or recommend a better text to the prof.

  • Maryann

    Hi Peter! Congratulations on your new baby! How wonderful! How is your daughter doing? How does she like being the big sister? Blessings to you all, maryann

    • All great. Thank you very much for asking. She’s a wonderful big sister.

  • lynda moyer

    Congratulations on your article in Wired Magazine and on your pursuit to better understand obesity!

  • sam

    Peter, is consuming MCT oil (or coconut oil) equivalent to taking synthetic ketones?

    (I have a friend with a brain tumor and she is pursuing a ketogenic diet. Supplementing ketones may be additive…)

    • No, though combining them seems to produce even higher levels of BHB. Exogenous ketones at the doses I consumed them were much more potent than MCTs.

  • Ellen Urciola

    Hi Peter,

    I completely missed Time’s June cover article, “Eat Butter” that begins to question their pontificating of Ansel Keyes.
    You, Dr. Lustig, Phinney, Volek, and others do a great job of bringing the fat debate to the public forum. I don’t know how I missed it (asleep at the switch). Now the whole dialogue a few posts before make sense when you asked about what kind of “revolution” (not the exact quote) some of us were talking about when it came to the fat debate.
    Yes, now might be the moment we (your readers) seek to tell our story of our fight and how Ansel Keyes ruined our lives with his faulty arguments. Maybe that grass root movement might begin with us telling our stories to magazines like Good Housekeeping, women’s day, Men’s Health, etc.

  • itai

    I have been reading some of your blog, especially the parts about ketosis. I have met some people(In Israel where I live) who claim they have been living without almost any calorie consumption(less than 500 a day) in the form of diluted juice for about 2 years. I met one of them for a conversation and am sure he is not making it up. he says he feels great and energetic(he is), not hungry, skinny(healthy), dosen’t lose weigh, and has very good blood test results including b12. I wonder If there is a scientific explanation for this phenomenon. I was thinking maybe ketosis could be it.
    I would very much appreciate an answer so i can stop wondering “how is this possible?!”.
    Thank you,

  • Sam

    Peter, if I am unable to reach ketosis via carb restriction (not starvation), does this imply that my insulin levels remain high (or at least too high to mobilize fat oxidation)?

  • Karen Hanes (Mucignat)

    Well, I really didn’t know a better way to say ‘hi’. Stumbled across your blog while researching Nutritional Ketogenic Diets (I’m now keto-adapted). It just dawned on me that we went to school together (I attended Mowat gr 9&10). My mom, Judy Mucignat (passed away 10 years ago) loved your mother and spoke very highly of your family. Anyway, I’m inspired by your research and was touched by your TED talk. It’s great to see the little boy become a warm, accomplished, family man. Good on ya.

    Karen (Mucignat) Hanes

    • Karen, I mentioned this to my mom and immediately remembered your mom and shared her fond memories. I’m sorry for your loss. Mowat seems soooooo far away….

  • Dan Walker

    Interesting coincidence, I went to what was at the time a junior high school named Mowat, but it’s all the way down in Florida. Mascots are even the same.
    Did you see the news about the success in converting stem cells into insulin producing beta cells? I haven’t had a chance to read much on it yet. Very promising!

    Congratulations on the newest Attia too!

    • Thank you. Yes, great implications for T1D patients.

  • Christian Selvaratnam

    Hi Peter – fascinating post. I have two questions. Firstly, does ingesting exogenous ketones confer an additional exercise advantage to someone with beta thalassemia trait/minor? I have this trait, my blood count is 11. Secondly, what would I buy /use to reproduce your experiment, it’s not just some MCT oil I think or is that as good? Many thanks. Christian

    • The treatment for low hemoglobin is transfusion or EPO. This is a problem of low oxygen carrying capacity.

  • Oscar


    Your blog is awesome. I’m a MS3 doing research at surg onc department, mainly bench research but I have some experience with epidemiological studies, although limited.

    Really enjoyed your TED-talk. Made me think. The attitude against obese patient I can really recognize from clinic.

    I love your posts discussing certain studies, it’s great to read someone else dissecting another study. It’s easy to just read the conclusions and think “nice study”. Our classes in medical statistics are mainly on a theoretical level and not really applied statistics, the problem is that the vast majority of class doesn’t have solid background in mathematics, so the classes are quite useless. It would definitely help with some applied statistics knowledge so you can actually interpret study results.

    Lastly, since started reading your blog about 1,5-2 months ago I have really became interested in nutrition overall. I’m in the beginning of a journey, having limited my carbs a quite a lot lately. I’m doing it slowly and doing parallel reading on the subject to optimize it in a good way that fits me. Not decided if I’m going to try a ketogenic diet, yet, but maybe later.

    Thanks again for putting in effort for a blog like this!

    • There may be no reason to, if you get enough benefit without it.

  • Shelli

    Hi Peter,
    Thank you for all of your generous and insightful expertise. I really appreciate it!
    2 quick questions I have about following a ketogenic diet:
    1-I’m an avid long distance day hiker. After following a ketogenic diet and having “trace ketones” for several weeks, I went on a 55-mile “almost hungry” fastpack. I hiked over 12,000′ of elevation gain over over the course of the 55 miles, and most of the hiking was at 10-12,500′. I’m training for a survivor show, so I wanted to see if I could do this almost hungry. I did. I ate only a 1/3 of a stick of butter each day, plus a handful of macadamia nuts, plus a half of a snickers bar, plus 6-8 pepperonies. I never bonked, and I covered the distance efficiently., But I did notice on the high altitude steep mountain climbs, I only had the low gear. I’m usually a power uphill hiker and being in ketosis definitely makes me feel like I have fewer gears. Again, it wasn’t a problem — I didn’t bonk, and I still got to where I need to go in reasonable time, but curious about your thoughts… is this just the way it is in ketosis? I can go long and steady no problem, but on upjills or interval-type stretches, I won’t bonk, but I’ll have only one low/slower gear? Please weigh in. Thanks!

    2–I’m Day 57 eating very low carbs… 20g at most most days… and eating lots of avocado, coconut oil, unsalted grassfed butter, eggs, etc. Still according to my Ketonix Sport, I’ve NEVER gone above “trace ketones.” After 51 days of using the ketonix, my best number is 7 blinking green lights. What gives?? Also, while I feel amazing, there is no fat or weight loss happening. Yes, I’m drinking tons of water, and I’m not overdoing it on the protein. I’m very active. I honestly don’t know why I’m not losing some fat… I would very much appreciate any insights you may have.

    Thanks a million if you could respond with thoughts,

    • Might be the case in the short run, though in the long run (for me it took about 18 months) I seemed to have both abilities. That said, ketosis is probably not the ideal diet for anaerobic activity.

    • Martin

      Shelli, as a trail runner and climber I can confirm what Peter says: it is well possible to maintain high power output on a ketogenic diet provided you give it enough time to adapt.

      Peter, if the anaerobic activity is taken out of the endurance context then it’s probably true that some combination of glucose and ketones (e.g. higher-carb diet with ketone supplementation) would work best. I am sure it would be the case for many olympic sports. But for real-life, outdoors activities it’s seldom the case 🙂

  • Laura

    I will save you the boring detail about my credentials and suffice it to say that what I love about you is that you are willing to be your own test case. I have been my own guinea pig for over 30 years, and your findings and mine are just about identical. When people ask me why I do what I do, I say, “If you had the most expensive sports car ever made, would you leave it in the hands of amateurs?”

    • Ahhh, the beauty of F1… riding right at the technical specification of a finely tuned machine.

  • Ben

    Just wondering if you would see the same results with anerobic exercise as you did here with aerobic exercise. Also in general do you find that training simultaneously over a period of time in both aerobic and anerobic exercise inhibits one from achieving maximal aerobic fitness and performance. In other words does anerobic training inhibit in some way aerobic performance?


  • Yossi Mandel

    Interesting hypothesis paper by our friend Rudolph Leibel on the search for the signal of the overfed state:


    It doesn’t reference the work of Mark Friedman at all, I’m assuming because they don’t believe the liver is relevant.

    Is there a leptin+unknowns hypothesis that runs contrary to the liver hypothesis? Or is there overlap?

  • JJ Bell

    Seems plausible, re the unexplained part, hepatic ATP anyone?

  • Justin Brown, D.O.

    Peter, thank you for the amazing information you have put forth thus far. I feel like I have a lot in common with the “old you”. I am 34 and am trying my hardest to remedy that situation (metabolic syndrome). I have been consistently in ketosis for about 2 months now and have seen improvements in weight/blood pressure, however my lipid profile looks atrocious (on Crestor). I’m certain my insulin resistance is playing a huge part in this. I recently had a NMR performed which indicated (to no surprise) that I was severely insulin resistant with a LP-IR score of 87. I was wondering if you know how high your score was initially and how long you feel until it took you to to “cure” your insulin resistance. I feel that it’s going to be a long road.

    • I only had an OGTT to go by, but I think OGTT (if done at 0, 60, 120 min with both glucose and insulin) is the best test we have outside of IVFSGTT or IST (the 2 “gold standards”).

  • Martin

    Hi Peter,
    good Maximal Fat Oxidation. My friend is mostly anaerobic athlete (Parkour, FreeRun) with VO2 max 55-60 mL/kg/min who has RQ 0.85 at 92% VO2 max. He burn more than 120 g fat per hour (2 g/min) and in one spiroergometry test burned 143 g/h. Lately he tested UCan SuperStarch during spiroergometry with good results.

    He (Warrior Diet) and me (I am in ketosis 4+ months) have problem (also during 24+ hours fasting) with BOHB levels. Most of times is around 0.5 mmoL/L (Precision Xtra ketomer) but on the basis of feeling (and diet and trainings), we have to be in ketosis. Our theory is that our tissues burn ketones really good so their levels not go much high. Somebody wants to have BOHB 1-2+ mmol, but that maybe means that his body don´t use ketones as well. Second options is that we have quite high acetoacetate, but ketomer cannot measure it. What is your opinion?

    Thanks 🙂

  • Nicky Hansard

    Hey pete, I was just doing a little research and came across some interesting studies concerning the ncor1 gene. I’d bet you’ve heard of it but I think it could have some pretty significant links to the ketogenic diet, I just couldn’t remember if you had mentioned it before.


    When that gene was disabled in the muscle cells of mice they became significantly stronger, larger and had increased endurance. Coincidentally the expression of that gene is down regulated during periods of increased fat oxidation e.g. during a ketogenic diet. When they knocked out the gene in fat cells the mice became obese BUT didn’t suffer any of the associated health concerns and even improved insulin sensitivity. I thought it was interesting stuff.

    A more in depth article:


    I’ll quote something from that article that really got my attention:

    ‘In our laboratory, we established how NCoR1 expression
    ties into metabolic homeostasis (Yamamoto et al. 2011).
    Low-glucose or high-fatty-acid levels were identified to
    decrease NCoR1 expression, while insulin and high-
    glucose levels increase its expression (Fig. 2A). Hence,
    NCoR1 levels are reduced in conditions favoring fatty
    acid oxidation in vitro and in vivo. In other words,
    NCoR1 activity is induced when glycolysis is favored
    over fat oxidation as energy source. These observations
    also demonstrate a logical and physiological link between
    the muscle- and adipocyte-specific NCoR1 models
    (Saltiel 2011); when glucose is available, NCoR1 dis-
    criminates against oxidative metabolism and fatty acid
    utilization to favor the use of glucose in the muscle. At
    the same time, adipogenesis is kept repressed. In case of
    the consumption of a high-fat diet, NCoR1 levels adapt
    by going down, thus allowing muscle to switch to
    oxidative metabolism and adipose tissue to store the
    excess fat.’

  • BL

    The physician’s assistant at my doctor’s office has scheduled me to see a cardiologist in January, mostly on general principles, I think (age).

    I understand cardiologists are generally anti-low-carb diets. Any advice if the matter comes up?

  • Oscar


    I wonder some about how you see on different careers that might negatively influence health. For instance, you did your residency at Hopkins and I guess you worked ~100h/week during quite long periods of your residency. I read somewhere that general surgery is the specialty where most are obese (I think >50% of the general surgeons were obese).

    I’m an European medical student working closely with surgeons in a research project, and sometimes they spend 7:00 am to 11pm in the OR. It’s not everyday but they don’t have the ideal situation to follow strict diets and so on. Rarely have any longer lunch breaks etc.

    1) Do you think you would have such sucessful outcomes as you have if you still were a surgeon at Hopkins? I’m aware you work a lot now too.
    2) How much of the health effects do you relate to diet? If you would construct a pie chart with: diet, exercise, sleep and genetics, what would that look like? I know this isn’t an easy question but an approximation would be fun to see 🙂

    Wish you further great sucess!

  • Peter,

    Super interesting stuff here. I was just started trying to get keto-adapted drinking a whiskey soda with my buddy John Markell, he said to look you up. I did and this stuff is great. As an exercise endurance nerd scientist myself I love this stuff. I tried to get in the FAT-ADAPT study on ultra runners, but was in the middle diet wise.

    So now my question. As for the lower O2 consumption on BHOB I wonder if any of that is from the extra energy is takes to makes BHOH from fatty acids rather than having directly at your disposal. You previously showed that it you lose about 20% of energy from deriving the ketones from fatty acids versus an exogenous supply, the aptly named Hall effect. Could this (in part) explain the -6% change in VO2 on exogenous BHOB?

    This maybe herisay, but what about a 3rd trial with an isocaloric CHO supplement? Of course being keto-adapted this would be tough to interpret. Double blind crossover study anyone?

    Last side point. I’m currently doing aging research and the NIA has an intervention testing program for potential anti-aging compounds. I was thinking about proposing BHOB although MCT had no effect (http://www.ncbi.nlm.nih.gov/pubmed/22451473).

    Looking forward to the next n=1 experiment.

    • Matthew, Veech et al. showed in rat hearts (the most “pure” model for work vs. O2 consumption) something like a 38% reduction in O2 requirement for a fixed work output. This was using BHB ester, which is what gave me the idea to try this “experiment.” Your question is a good one–is the same effect found in NK. I suspect the answer is yes, because the arbitrage of energy comes from the krebs cycle, where BHB is “consumed” not from the process of generating ketones, I can’t be sure without an experiment, preferably much more rigorous than the one I did.

    • Rob Coberly

      Why not propose BHB, or a BHB/ACA combination in physiologic proportions?
      1: Edwards C, Canfield J, Copes N, Rehan M, Lipps D, Bradshaw PC.
      D-beta-hydroxybutyrate extends lifespan in C. elegans. Aging (Albany NY). 2014
      Aug;6(8):621-44. PubMed PMID: 25127866; PubMed Central PMCID: PMC4169858.
      …This effect appears related to HDAC inhibition, about which it’s also quite worthwhile to read the reviews from Eric Verdin and JC Newman. Also,
      1: Scheibye-Knudsen M, Mitchell SJ, Fang EF, Iyama T, Ward T, Wang J, Dunn CA,
      Singh N, Veith S, Hasan-Olive MM, Mangerich A, Wilson MA, Mattson MP, Bergersen
      LH, Cogger VC, Warren A, Le Couteur DG, Moaddel R, Wilson DM 3rd, Croteau DL, de
      Cabo R, Bohr VA. A high-fat diet and NAD(+) activate Sirt1 to rescue premature
      aging in cockayne syndrome. Cell Metab. 2014 Nov 4;20(5):840-55. doi:
      10.1016/j.cmet.2014.10.005. Epub 2014 Nov 4. PubMed PMID: 25440059; PubMed
      Central PMCID: PMC4261735.
      …Plenty of thought-provoking stuff here, BHB is one of the experimental conditions in play, appears that both BHB and the sirtuin cofactor NAD+ can activate SIRT1 and rescue a premature aging phenotype.

    • Matt

      Its a good point Rob and I am actually quite familiar with the Verdin paper (and the lifespan extension in worms). The BHB HDAC connection is an interesting one that we are playing with a little in lab also.

      A recent paper did look at the effects of exogenous BHB supplementation during exercise and at rest, showing a decrease in circulating glucose AND lipolysis (without an increase in insulin) suggesting a mechanism distinct from merely having low glycogen stores and low insulin in regulating lipolysis.

      Systemic, cerebral and skeletal muscle ketone body and energy metabolism during acute hyper-D-?-hydroxybutyrataemia in post-absorptive healthy males.

      J Clin Endocrinol Metab. 2014 Nov 21;:jc20142608

      Authors: Mikkelsen KH, Seifert T, Secher NH, Grøndal T, van Hall G

      The main conclusions: “Results: 1. An increase in HOB from the basal 160 to 450 ?mol/L elicited 14±2% reduction (P=0.03) in glucose appearance and 37±4% decrease (P=0.03) in lipolytic rate while insulin and glucagon were unchanged; 2. Endogenous HOB appearance was reduced in a dose-dependent manner with complete inhibition at the highest HOB concentration (1.7 mmol/L); 3. Cerebral HOB uptake and subsequent oxidation was linearly related to the arterial HOB concentration; 4. Resting skeletal muscle HOB uptake showed saturation kinetics.”

  • Edwin Ek

    Re your August 31 post.

    Stumbled on this website today. Seems like work and analysis done to a reasonably high standard. But, there is an enormous argument against using ketones as fuel, and that is the inescapable concomitant damage to the endothelium. Not by the ketones themselves (I am unaware of any studies showing direct harm) but by the diet necessary to achieve ketosis.

    Chronic damage to the endothelium is the gateway to atherosclerotic heart disease. Caldwell Esselstyn has been instrumental in bringing attention to this.

  • Lewis Jordan Owen

    So, I started reading this blog back in April. On the 20th of April I went lchf. 50+ lbs later i don’t even use a scale anymore because look and feel so good. Hiking for hours is super easy, eating 1-2 times a day is so convenient, and not restricting portions is a huge stress relief.

    Thank you, I really appreciate the information and recommend it often to those that are interested. Again thank you. Cant wait for the next post.

  • Ana

    Peter, I was wondering whether you can discuss at some point the interaction between a LCHF diet and Tamixifen. Been taking Tamoxifen for almost two years and following a LCHF diet but have belly fat accumulation that is really demoralizing. Exercising 3x/wk also. Tamixifen did get me to menopause…any help appreciated.

  • Stephanie

    Hi Peter,

    I’m seriously considering a career as a dietitian as I would like to a) learn more about the “science” behind nutrition for my personal benefit and b) be able to disseminate this information and encourage others to lead healthier lives, specifically the geriatric population for whom a healthy lifestyle is paramount. I’m glad I came across your TED talk and blog at this time; your commitment to bringing the “real science” to the fore of nutrition education is exactly what I hope to embody in my future (potential) career. Do you have an opinion on the current standards required of Registered Dietitians? I’ve searched “dietitian” on your blog and it seems you lump them with other licensed healthcare workers that subscribe to the conventional and problematic wisdom about nutrition. Since registered dietitians are at the front line of being the “authority” on diet in hospital settings, restaurants, prisons, schools, the world over, what would you say to aspiring dietitians such that they could be assets in this movement you are spearheading (hope you don’t mind if I put it that way) to conscientiously purvey the current and evolving science of nutrition?

    • Typically an RD is earned after a bachelor’s degree.

  • Dominick

    I stumbled onto you blog earlier this year and my life has not been the same since. It took me a while to adjust and fine tune my eating. I currently maintain a diet that is 75% Fat, 25% Protein, and 5% Carbs. I have never felt better and I’ve also lost 30 lbs in about 4 months. Thank you for all that you do, I am sure you are helping many to get control of they lives. Merry Christmas and Happy New Year!!

    • Thank you, Dominick, and congrats on your journey.

  • Heidi

    Hi Peter,

    I’ve been ‘keto-adapted’ for a year (and feel the many benefits of it). I recently had a few nosebleeds (three this week) and in my quick online search, found a lack of vitamin k could be the culprit. I do eat salads and veggies, and the occasional wilted kale or swiss chard, but could probably increase those a bit. But in my search, I also came across a number of discussions regarding the “fact” (?) that a ketogenic diet makes the blood “sticky” and several people (online) related that to their own blood clots/embolism events. Can you weigh-in on this topic, and the risks associated (and how to mitigate?). Thanks in advance for your reply.

    • News to me. Also, if ketosis leads to hypercoagulability, wouldn’t you be less likely to have nosebleeds?

  • Dave

    I’m very confused about the digestion of Fat.

    I read that solid human waste typically contains between 10 to 20% Cholesterol and other Fats.

    So… The calories from those fats were never absorbed or metabolized and you never had to burn them.

    To my limited knowledge… Fats are the only type of digestible, food-stuff in human waste.

    Everything else – If we can digest it and metabolize it then we eventually need to burn it.

    But – How does that work?

    Why is there any Fat at all in Human Waste? Why don’t we absorb and metabolize 100% of the Fat we eat like we do with every other type of digestible food we eat?

    And – What is the Fat content of waste from a person who lives on a diet that’s 80% fat?

    What % of Calories from Fat passes through the body without being absorbed and metabolized?

    Thanks for all your hard work.

    • Dave, except in cases of malabsorption, there is actually very little fat in human stool. We’re pretty efficient at absorbing it.

    • JJ Bell

      Dave – I have heard of a couple of studies where high dairy/calcium diets can increase fat excretion but this is likely related to malabsorption as per Peter’s comments.

      Peter – Thanks for recent talk with Ben Greenfield & podcast with Tim Ferriss -> both excellent. A Christmas bonus for a geek like me. Your fans will know you do not make many appearances (given constraints on your time), but when you do, standard of info is second to none.

      PS, Is NuSi due to publish results of Energy Balance Consortium study anytime soon? (think it was due to close last June?)

      • I think Tim and I will do a part II in early ’15. Long way from pub.

    • JJ Bell

      Always happy to wait as standard is so high (you have a small captive audience I imagine).
      Looking forward to round 2 with Tim.
      FYI, not a wealthy chap but just donated to the NAFLD study ($200K of donations are being matched, how great is that?!), tis the season – hope you have a great one.

      Forever thankful for all your hard work, means the world to a time-starved, information-starved geek like me.

  • vicky melissas

    Hi Peter
    I have only recently discovered your blog and there is much to learn. I have a question re serum insulin levels. I am currently in my fourth week of lchf diet. Before I started fasting bg was 5.9 mmol/l and fasting insulin was sitting at 27.
    Do you have information regarding how insulin levels reduce with this type of diet. I’m currently in ketosis levels any where between 2.7 to 1.00mmol/l and i have noticed fasting bg now sitting at ave 5.4mmol/l. I’m curious to see how longit will take to get normal insulin levels again.

    • Highly variable–and in some people, for reasons we don’t know, it may get worse–but improved hyperinsulinemia can improve inside of 3 months.

  • Victor Heredia

    Hi Peter,

    Loved your interview with Tim Ferriss. And this Blog. Great stuff. Although I am not a researcher by profession I’ve done quite a bit research on cancer and “best” supplements.

    If I may ask, what are you thoughts on the following:
    (I take all of these for optional health)

    1) Baking Soda: I take this daily based on the Italian Oncologist Dr.Simoncini’s research it kills cancer cells.
    2) Royal Jelly: For anti-aging and immune support. And overall superhumaness. =)
    3) Colostrum: Miracle food for immune support and recovery.
    4) Bee Pollen

    When was younger I would get colds often and was told by a microbiologist that I was “Strong as a horse but have a weak immune system” The above-mentioned made a drastic change in my health and have not had a cold for over a day in 3 years.

    Your thoughts on the above?

    Also any recommendations for elevated liver enzymes? 3 years ago I ruptured a disc deadlifling and over did it on Ibuprofen. (I foolishly did not bother to research the side affects of this)

    Thanks Peter.

  • JB

    Interesting that in the second trial, glucose went down, VCO2 and RQ increased (versus first trial). I know you phrased the explanation as the “VCO2 didn’t go down as much as the VO2”, but if someone just put the numbers for glucose, VCO2 and RQ in front of me without the addition of the BHB data, I’d say the person was utilizing more carbohydrate. Is it possible the exogenous BHB allows for greater non-oxidative glycolysis at lower VO2’s? You didn’t happen to measure lactate, did you? Also, were the differences between the trials significant? Thanks for your always great posts

  • JB

    I have just read far enough down in the comments to find that you have a new baby. Congratulations to you and your family!

    I’ve been amazed that you’ve continued to blog at all since the founding of NuSI. I, for one, have learned so much from this blog, that if you never write another word (including the final cholesterol, insulin and/or thyroid posts – did that just make you break out into an anxiety sweat? haha), I would be a happy camper because you dropped crumbs and laid foundations for people to easily continue their self education with a strong direction.

    Maybe with a new baby, you’re getting even less sleep, so you blog on, but no matter what or when you choose to write, it’s very much appreciated

    • Thanks, JB. Little guy is 4 months old today, actually. I’m not sure one could say that I “continue” blogging, but I guess I still keep the blog up…

  • Susan

    I want to pass along appreciation for you work. After my dad had a stent and was treated for prostate cancer he followed Esselstyn’s very low fat diet, ground his own grains, made his own sour dough starter ; did all the “right” things. Initially he felt better, perhaps because he cut out the cookies and other sugars, but after about a year of that he was feeling tired. His cholesterol had gone up, and he needed 3 more stents. He was pretty disappointed. Then he found your blog. He has cut out all grains, eats animal fats and non starchy veggies, feels better and last cholesterol check was down. I’m also following a much lower carb diet and feeling better. Thank you for putting your work out there, and providing the information for people to improve health and life.

    • Susan, thanks for sharing your experience (and especially that of your dad). I do hope your dad has a thoughtful cardiologist looking after him who is more interested in his LDL-P and Lp(a)-P than just “cholesterol.” Advanced testing of lipoproteins is essential, in my opinion, for anyone with a significant risk profile for CHD.

  • Anna

    Hi Peter,

    As you are one of the few people I truly trust in this emerging and controversial field, I was hoping for some (quick) advice about how to eat while pregnant. I know this is a upcoming topic on your blog, but I am newly pregnant and anxious to do the right thing.

    I’ve been mostly in ketosis since September, normal weight, and workout (Pure Barre) about 3x/week. My only negative symptoms from this diet is my hair started falling out a bit more in month 3, and my blood pressure is even lower than normal (so I have to stand up slowly, but it’s not a big deal). I eat a salad (and a prenatal) a day, but way fewer fruits than I used to. I know the research is mixed at best about fruits and veggies being good for you, but it’s still a bit scary not focusing on those when I’m pregnant.

    In sum, would you recommend being in nutritional ketosis while pregnant? I just can’t find solid research where I’ve been looking.

    Thanks for your time and for everything you’re doing. Your efforts mean so much to so many people.


    • Anna, there are no data to my knowledge that a ketogenic diet is ideal during pregnancy, and I would be reluctant to suggest it is. So knowing nothing, I would *assume* the optimal diet would contain some starch, in addition the foods you’re probably already eating.
      My guess, by the way, based on the FGF-21 literature, is that ketosis would not support fertility in females.

  • gkern

    Peter, have you done any research on MAP a “master amino acid” supplement. I have been using MAP as part of my training which is nothing compared to the stuff you are discussing.

    Here is my problem, when I use MAP in conjunction with other supplement, my heart rate during a run is very slow. Yesterday I did a 4.5 mile run. My average rate 89 bpm. For the first 3 miles my hr climbed from 55 bpm to 75 bpm. At about the three mile mark my hear rate went from 75 to 150-160 range.

    I am trying to understand if this is an energy metabolism issue and if there are health risks associated with the protocol. I am going to discuss with my family doctor could address but I am not sure if he has the necessary background in area of bio energy and supplement… (I was thinking of your ketosis warning to your patient on the Atkins’ diet). MAP seems to be the common element in my the slow heart rate while racing or training. When I don’t follow the protocol my heart rate would climb quickly to 125 and then gradually increase to 145…165 depending on speed and distance. Any thoughts on MAP? NOTHING ON THE MAP SITE ABOUT ANY AFFECT ON HEART RATE.

  • Marcos

    Hey Peter! Greetings from Spain! Huge fan of your work.

    I wanted to ask you a question from the evolutionary standpoint. I always think that when we’re discussing the ideal diet and lifestyle for the human being, we must consider evolutionary biology and what we evolved to thrive on. But when I try to figure out what that is, there seems to be something missing.

    Our ancestors were hunter-gatherers, and their diet was probably mainly composed by nuts and seeds, plants and vegetables available in their surroundings and the occasional hunt and access to animal protein and fat. But here’s my question: doesn’t it seem like compared to today, our ancestors would only have access to far less calories and yet not only did they survive but they supposedly thrived on that? I just find it almost impossible that our ancestors would be able to find that many calories on a daily basis. And being in the wild, they needed to have adequate muscle mass and energy to survive yet alone to thrive.

    The only possible explanation I see is efficiency. Their energy expenditure and micronutrient use must have been vastly more efficient. Their lifestyle would probably be much closer to Intermittent Fasting, which stimulates the body to be more efficient because of the scarcity of food. I know IF is on your ‘coming soon’ list and this a very broad question but I wanted to get your thoughts on that since to me there seems to be a huge disconnect between the daily caloric consumption, and yet that’s how our ancestors have lived for millions of years and supposedly thrived on that.

    • Certainly long enough periods of exposure to fasting could lower energy expenditure (i.e., more “efficiency”), but it’s also worth noting that studies of modern day HG societies with doubly-labeled water suggest they actually expend less overall energy (deliberate + nondeliberate) that “modern” man, in part because when they aren’t looking for food or reproducing, they are laying low and preserving energy.

  • Mike

    I came across your blog after the Tim Ferris show. I’m training for an Ironman August ’15 (completed a half years ago). I generally eat low carb anyway so I’m enjoying reading how to utilize energy.

    Also, I’m shopping for synthetic ketones because like you, I assume I can tolerate poor tasting supplements. I found KetoForce, but I’ll keep looking.


  • David Jackemeyer

    *Always* stimulating to end my night reading your thoughts, thank you for your focused & steady work 🙂
    1) Why do you think you start out w/ such high RQ? Is this more measurement error due to being rested while using a high-flow cart?
    2) Along the same thoughts, should we not ignore the first 5-min avg since it includes that ramping up time (probably a lot of error before reaching steady HR)?
    3) What happened during those two ^–^ during the third quarter of Test set #1? Did someone make you laugh?
    4) Mon morning QB comment here: upon viewing these two results, I did not see a difference — instead, I would be back to the drawing board. Will you go back to the drawing board?

    Lastly, the first table has an error, and I notice an unlikely coincidence: the first 5min of O2 consumed is equivalent to the last 5min of CO2 exhaled, the latter out of place. CO2 out was dropping in last 5 min.

    I hope this is constructive contribution to your efforts. I’m nose-to-the drawing board, seeing if I can prep to detect EPOC. Best cheers and wishes for you & yours, DJ

    • I have no plans any time soon to work on this. Not high enough on the priority list relative to other demands. Hope others do.

    • David Jackemeyer

      Understood, and respected.
      BTW, after listening intently and repeatedly to your Tim Ferris discussion, I gobbled up “Mistakes were made … BUT NOT BY ME!” (emphasis mine, reflecting my own struggles with this very issue). Many thanks for recommending it in the public space!
      A quote, “Science, a form of arrogance control”
      Love it!

      Again, best to your and yours!

      • Glad you enjoyed. Since reading this book, Carol has become a close friend and is now an adviser to NuSI.

  • Will

    Great post. I’m struggling to find any toxicology reports on 1-3 butanediol. Specifically I’m interested in the enantiomers. I’ve ordered a racemic mixture which should negate any issues as Veech, R. L (2003) states we utilise both forms of Beta-Hydroxybutyrate. Just wondered if you had more insight? Cheers, Will.

    • Rob Coberly

      I didn’t think L-beta-hydroxybutyrate had a particular metabolic path. Re the enantiomers of the BHB and the butanediol, Clarke and Veech’s most recent patent of the ester (there is a series of them, this is 2014), US 8,642,654 B2 elaborates:
      “…one particular enantiomer of one particular ester of 3-hydroxybutyrate is an effective and palatable precursor to the ketone body (3R) hydroxybutyrate.Accordingly,the present invention provides a compound which is 3-hydroxybutyl 3-hydroxybutyrate enantiomerically enriched with respect to (3R)-hydroxybutyl (3R)-hydroxybutyrate… prepared by a process which comprises carrying out a trans-esterification reaction between ethyl (3R)-hydroxybutyrate and (3R)-1, 3-butanediol in the presence of a lipase enzyme… Two particular advantages are…First, the (3R, 3R‘) enantiomer is palatable and is less bitter-tasting than other ketone bodies.It is therefore particularly well-suited for oral administration. This contrasts with many other ketone bodies, and their precursors, which are notoriously bad-tasting and thus difficult to tolerate when taken orally.Second,the(3R,3R‘)enantiomer is cleaved in vivo to form(3R)-hydroxybutyrate and (R)-1,3 butanediol. The (3R)-hydroxybutyrate is released immediately,giving a rapid effect following ingestion.The(R)-1,3 butanediol is converted in the liver to (3R)-hydroxybutyrate which is then released into blood.Overall this gives a favourable pharmacokinetic profile,since raised blood levels of the desired(R)-3-hydroxybutyrate are both achieved quickly and then sustained over a period of time following ingestion of the compound of the invention.”

  • Martin

    Hi Dr. Attia,
    I would like to know what is your VO2 max? On the basis data from this experiment, I guess 5 000 L/min (78 kg = 64.1 ml/kg/min)

    But after your first 12-weeks experiment your VO2 max go down from 4 960 mL/min (63.5 mL/min/kg) to 4 350 mL/min (55.7 mL/min/kg). http://eatingacademy.com/how-a-low-carb-diet-affected-my-athletic-performance

    I think it was caused maybe because you couldn´t ride more in low glycogen state. What you think?

    Thank you

    • Martin

      Respectively, did increase NK your VO2 max? Dr. Jack Kruse claims that NK increasing VO2 max, but it may takes 26-36 months. And it should be connect with cold thermogenesis (CT)- http://jackkruse.com/cold-thermogenesis-1-theory-to-practice-begins/

      Do you practice CT?

      So I have 3 Q:
      What is your VO2 max?

      Did increase NK your VO2 max?

      Do you practice CT?

      Thank you

      • I don’t practice CT, but I’m looking into WBC. Not sure if NK impacted (long term) my VO2 max. Also not sure VO2 max matters that much.

    • Over the past 2 years it has varied quite a bit by weight and training. “Good” is in the range of 5.2 to 5.3 L/min at 76 to 77 kg (67 to 70 ml/min/kg). “Bad” is in the range of 4.7 to 4.9 L/min at 78 to 79 kg (59 to 63 ml/min/kg).

  • Leo

    Hi Peter, which product did you use for this experiment?

  • Matt Frailey

    Hello Peter, I really respect you and admire your approach and thinking to diets and health, which often goes against the mainstream. Anyway could I please get your thoughts about Gout? The conventional wisdom or what most doctors tell folks is to cut out all or most red meats, proteins, and eat a lot of carbohydrates and fruits etc. However my hunch is that lower carb diets are actually better for gout in the long run and do not greatly increase Uric Acid levels and may in fact lower than which is against the mainstream thoughts.

    I’ve been reading some articles that suggest that fructose actually greatly increased uric acid levels in the body vs decreasing it – which would go against the general consensus of eating large amounts of fruit etc. What are your thoughts on this?

    I used to do low carb fairly consistently 8 – 10 years ago, then got off it for some reason, and stopped working out, gained a bunch of weight etc. Anyway I’ve been wanting to go back to the low carb lifestyle in a big way and get back to working out like I used to with weights, however I recently had an episode of gout, which I never had in my life, should I have any worries about going back to low carb? My though is that in the beginning phases could be at risk, however overall I think eating low carb is actually better and will benefit me.

    anyway I would love to get your general thoughts on this as you seem to know your biochemistry very well and may have some theories


    • It might be a bit of both and might depend on the individual and other factors. I think there are good explanations for both the “too much protein” and “too much sugar (fructose)” route, though the former is considered the conventional wisdom. To read up on the latter, check out the work of Richard Johnson at the University of Colorado. His book (I think it’s called Fat Switch or something like that) is good.

  • Roberto

    Hi Peter: What is your view on creatine, arginine and alanine supplements?

  • Robert Totten

    I’ve been on a Ketogenic diet for several months now, and started checking my blood with a meter for the first time January 01, 2015. I’m in Ketosis every time I take a reading, however my numbers only range between .7 and .9. Once in a while I’ll hit 1.0 to 2.0 at the most. What do I have to do to get above 2.0 more consistently, and does it matter? I can honestly say I feel a certain degree of mental clarity as it is, but can that improve with higher numbers, and can you feel a difference?
    Thank you,

  • pone

    You have one other article with VO2Max testing here:

    and in that you give a very useful linear relationship where the percent of fat used in aerobic metabolism is a function of CO2 over O2. Do you happen to have the actual equation for that relationship or an idea where to find it? The reason to have the actual equation is so we can modify our own VO2Max test data and do calculations at each level of exertion about the approximate amount of fat and glucose being used at those levels.

    • Yes, to a first order it’s dervived by know that RQ=0.7 is approx 100% fat ox and RQ=1.0 is approx 100% CHO ox. Linear equation.

  • ron toledo

    Good morning all!

    I have been follwing a keto lifestyle for a couple months now. It is a personal experiment to see how I can push my performance to the next level. I will be running a Half Marathon on this specific nutritional lifestyle.

    In previous races, I had relied greatly on Carbs as energy. My traditional “final prep” is described below:

    *The Night Before the Race*
    Eat a big meal at least 12 hours before race time. Don’t eat anything that you haven’t had before or something that bothers your stomach. No dessert, no salad. After this meal take a light walk.

    *Race Morning*
    *4 hours prior to the start*
    Ingest 1.5 to 2 grams of carbohydrate per pound of my body weight. Taken through a liquid carb drink and the rest in bagels, bread, bananas, honey… whatever is best. Drink AT LEAST 32 ounces of water with this meal to start the digestive process and the water does this.

    *Two hours prior to the start*
    Ingest .5 to 1 gram of carbohydrate and AT LEAST 24 ounces of water.

    *One hour prior to the start*
    Ingest a small carbohydrate snack and 16 ounces of water or Gatorade. Powerbars etc. seem to have a bad effect, fresh stuff like bread and honey, and bananas seemed to work well.

    *10 minutes prior to the start*
    Drink 10 ounces of sports drink. I like accelerade because it has some carb and protein.

    What race day nutrition would be most beneficial for a body in ketosis? As far as supplements, I am equipped with UCAN Superstarch and Vespa energy packets. I am looking for information to consider in regards to what I should look to eat the night before and the final hours leading up to the race. Any information to share is greatly appreciated. Thanks!

  • pone

    I have tried the BodyBio brand Sodium/Potassium Butyrate which contains about 500 mg of butyric acid. It runs straight through me. I find that odd since butyrate is supposed to nourishing to the gut. I would really like to understand the physiology of why some of us cannot tolerate it. I thought it was just me until your report in this article.

  • pone

    Just small correction. In article you say that RQ is calculated as the ratio of VO2 and VCO2. It is the inverse, the ratio of VCO2 over VO2. Technically, that ratio for a whole body measurement is RER. RQ refers to that same measurement in a specific muscle group, which in this case you probably did not have. So you were probably measuring RER = VCO2/O2

  • Dale Charles

    I just found this site and really like the discussions. I am a powerlifter and KB lifter and have experienced the exact same result. I am talking glucose and ketone blood readings before and after training sessions. I am starting to suspect it is related to volume. On my high volume days (usually squat/deadlift), my glucose number goes up 50 points and my ketones drop. On these days I also have several sets of high intensity. I have also gotten a large glucose spike on an extreme KB day, but not with a more normal workload. The swing is less with lighter days. I am experimenting with different loads and volume and also with different supplements. Coconut oil before training seems to help on the light/medium days but not on the days with a heavier load. I want to minimize the glucose rise, so any ideas would be appreciated.

  • Erin

    Hi Peter,
    Have you thought much about how ketogenic states or NK might be applicable to folks with glycogen storage diseases? IE – Phosphoralayse Deficiency/ McArdle’s disease. Many patients with McArdle’s are self-experimenting with ketosis and there is anecdotal/ common-sensical reason to believe someone who can’t access muscle stored glycogen could enter into ketosis more quickly than the average Joe/Jane and alleviate symptoms of exercise intolerance. The problem with most experiments on McArdle’s is that there are so few people to merit good clinical trials, so patients end up self-testing and reporting it back (*with giant disclaimers*) to the group (see the “Ketosis in Mcardle’s” facebook group, or self-published blogs by people w/ McArdle’s). I have McArdle’s (though milder symptoms, for some reason, than most) and would like to work with a nutritionist to monitor NK and improved exercise performance, but have had trouble finding docs/ nutritionists who are educated enough to really feel comfortable recommending ketosis. Any chance you know of a like-minded colleague in the Central Texas (Austin) area?

    • Yes, I’ve thought about this a lot and have even tried to talk some folks into doing a clinical trial of NK supplemented with UCAN (which has made a big difference in GSD).
      I agree with your hypothesis, but I don’t know who you could see in Austin. Sorry.

  • HELP–SFA and LCHF diet for CKDisease stage 3-5 is untested. Yet diabetics benefit nd improve greatly from this diet. But with a single kidney, and filtration issues (low eGFR) I need to learn how HF in my diet (NOT high protein – the 40-60gr daily of protein serve me well) but how FATS may harm filtration? I am looking for the SWEET SPOT of fat I can consume for health, stave off dialysis, and weight loss. ( ALL other factors, BP, sleep, meds, Trig.LDL,etc are perfect, but weight loss needed, <13 lbs in 45 days on LCHF. Ideal protein for me is dairy-full fat yogurt, cheese, butter, eggs, hemp protein, <50 carbs.)

    thanks- here is one study:
    http://www.renalandurologynews.com/high-fat-low-carb-diet-beneficial-for-ckd-patients/article/314032/ << last line confirms NO studies on CKD3-5 who MIGHT benefit the most!!!

    Can you provide more info or your thoughts? Most nephrologists are old school, no idea on nutritional ketosis, or most dietitians either. they all freak at the word HF, and still relate it to CHD causing…

    you said:
    Dr. Peter Attia is a very-low-carbohydrate, ketogenic diet proponent who believes that elevated LDL-P values warrant dietary modification, including reduction in saturated fatty acid (SFA) intake. I He goes on to say: "While I believe the population-based guidelines for SFA are not supported by a standard of science I consider acceptable, it does not imply I believe SFA is uniformly safe at all levels for all individuals."

  • Paul Arena

    Hey Peter,
    Interesting anecdote to report and wondering if you or anybody else can sympathize. Being in ketosis seems to make my vision BETTER. I’ve been keto for about 2 years with obvious junky carb days when willpower is low. Those junky carb days are then followed by a day or two of slightly blurry vision. Better vision comes back with MCT oil coffee and resumption of keto diet.

    • Interesting. I have not heard that before.

    • Several people have reported to me improved vision with the ketogenic diet and ketogenic supplementation (MCT and BHB salts). This may be due to lowering of blood glucose and improved blood flow associated with ketone metabolism

    • sean omara, md

      Paleo x 5 years with increasing ketogenic dieting x 1.5 years. Today while on a extended fast (48 hours into zero calorie only water fast ) I noticed I can read without glasses for the first time in probably 15 years. I estimate improved vision of about 35-40% over baseline but enough to read without glasses.

      I plan to follow this more by standardized vision testing on fasting days comparing to feeding days. I do IF regularly 18-20 hours a day. Absolutely fascinating.

    • Walter

      For what it’s worth, at my last eye test the optician reported that my eyesight had in fact somewhat surprisingly improved, so I seem to be more anecdotal evidence in line with the above/below comments. Context: I have astigmatism which affects my far-sight, and at this point when the test was done, I had been on a ketogenic diet and had substantially adapted, having been on it for perhaps 9-12 months which sprang from my interest in endurance running. I am 45 y/o. And as I say, during testing it became obvious my far-sight had apparently improved noticeably. She mentioned that far-sigh sometimes improves as a result of progressing age, but that this usually coincides with weakening near-sight, due to the hardening of the eye lens etc. However whereas my far-sight had measurably improved there were no indication of any weakening of near-sight. Her comment was just “Keep doing whatever you’re doing.” 🙂

  • Greg Hanssen

    I’ve been upping my fat intake (mostly unsaturated) over the last 6 months via tweaked Soylent and am very interested as an endurance athlete about the ability to oxidize more fat at higher heat rates. Is there any way a person on a budget can get a sense during a workout of their fat vs cho oxidation? I can’t even afford (or should I say, justify) a power meter for the bike… Is there any correlation between V02 (or simple breathing rate) and fat vs cho oxidation for the same power output? I suppose if someone does ever make a wrist worn device that could report instantaneous fat vs cho calorie consumption they’ll do well selling to the endurance athletes out there..

  • Anna

    I am a female professional cyclist and am very interested in learning more about utilizing a higher ketosis diet. My first question would be, can I sustain this type of diet during the racing season when I will have to go anaerobic at some points during races or should I reserve implementing a higher ketosis diet during off-season when I am doing more aerobic base type training?
    I also administer metabolic testing at a facility in Scottsdale, AZ and see numerous athletes everyday who may benefit from utilizing a ketosis diet. Where can I send them for more information on how to go about creating a keto diet that is specific to them and their training objectives?
    Thank you for your help. I look forward to hearing back from you. Smiles.

    • Derek Congelliere

      Very fascinated by this topic and any research and observations that have been made. Ready to share the ability to add ketones into the body through a much more pleasant and tasty method than in your research… reaching ketosis in under 59 minutes. http://www.facebook.com/pruvitnow I would enjoy your feedback as a professional in the field.

    • Chris

      Anna- I am also a cyclist and have been playing around with Exogenous Ketones. Seeing interesting results from them and so far a big fan. They are available now to the market place and so far anybody on the cycling front I know of are seeing good results from them.

    • Philip

      I am an endurance athlete and suspect I have been training in a state of ketosis for many years.
      I have been doing long runs and bike rides without ingesting much and training my body to burn fat for energy. I was interested to read your entry Ketosis part 2 as it relates to aerobic exercise.
      Is it possible to starve the liver of glycogen and cause damage to it through exercising in ketosis.

  • Lori

    Hi Dr. Attia,

    Have you heard of or tried Keto-OS by Pruvit? It is based on BHB salts and coconut. It is revolutionary. The taste is phenomenal and will provide the results you were seeking with this experiment. Please email me for more details 🙂

    Lori, MS, RD, CSCS

    • Deborah

      I have just started taking KETO-OS and have noticed a huge difference in my energy levels as well as mental clarity. On concern I have that no one has brought up yet is, does this in any way have a negative effect on the liver? Also, there is a lot of sodium in this product 40%, is this a concern for blood pressure at all?

  • Ericka

    I am also interested in your feedback on keto//os and answers to the questions about liver…and not so I can sell it–I really could care less. I really would love your expertise on what we are ingesting. Mytime.justpruvit.com is the link to the keto//os info.

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  • Rhiannon

    Looking to purchase exogenous ketones, Is there a brand that is recommended?

  • Jeff

    I don’t know if you have heard of this, but in India and several other countries, some individuals drink their own urine. It is said to be particularly effective in the morning and when fasting, and to be very beneficial to one’s health. The morning and fasting would also be the times that higher levels of ketones would be in the urine, is that correct? I’m not aware of any scientific studies, but for better or worse here is a wikipedia link: https://en.wikipedia.org/wiki/Urophagia

  • Carlos Castro


    Came across your work thanks to Tim Ferris’ podcast featuring you. I plan to try to absorb as much of the information you are sharing in your blog. Thank you for putting it out.

    As a competitive rower training 4-6 hours/day, a father of 5, and a full time IT employee; I find it sometimes difficult to keep my mental focus. I have utilized ketosis in my journey from being a 450lb couch potato to 220lb rower still struggling to lose the last 20 or so pounds to allow me to make my really fly.

    What I have absorbed so far has been enlightening but has brought up a bunch questions, which I will wait to ask after I have done the adequate reading.

    Again, thank you for your work, and self-experimentation.


  • michael troup

    Interesting. You state that O2 consumption should be the same for the same amount of work – I thought that burning fat needed slightly more O2 per molecule of ATP produced. As to the very different O2 consumptions in your two tests – do you have the biochemical explanation for this? Presumably it relates to how BHB is metabolised and how many ATP molecules are produced per O2 used, but it would be nice to know the details.

    • I think I wrote about extensively in another series on ketosis. It has to do with delta G.

  • michael troup

    Looking at your AT pre vs during ketosis, you used more O2 in ketosis, but how much more work were you actually doing? Same question at VO2max. After all it is how fast you are going, not how much O2 you are using, that wins prizes. Thanks.

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  • Tim


    I would love to send you some samples of an exogenous ketone product I came across. Several years ago, I put myself into ketosis through diet and felt great! This product makes me feel the same way. I would love to get your opinion of this product.


  • Prady

    Hi Peter, huge fan of your work, your podcast with Tim and your blog… I started Ketogenic diet after listening to your podcast and Dr. D’Agastino with Tim Ferris… I did 90% fat and less than 20g of carbs and 30-50g of protein for 3 weeks to get keto adapted… I was using a blood ketone tester to keep track of my ketosis… I was in ketosis after the 2nd day of starting my diet and in 3 weeks, the highest I tracked was 4.5 mmol/L of ketones… All good there…

    I then did a cheat day last week, on Sunday, and after that day, I have been on the same diet I followed previously, but my ketone levels have not gone above 0.7 mmol/L and most times it is below 0.5 mmol/L… I am not eating too much carbs or protein… I have stopped taking protein supplements… I drink 3-4 Bulletproof Coffee a day with a extra-large serving of butter and MCT oils and lunch is half a roast chicken with lot of MCT oil and at night usually 6 eggs or 500g of steak with a lot of butter…

    I also workout 3-4 days, heavy weight training and some HIIT on a treadmill.

    Do you see any mistakes in the diet or anything else I could do to get past the block? It has been 5 days since I am back on the diet after the cheat day… Appreciate you reading this and your help… Thanks.

    • Maarten

      First of all, great stuff here!

      I am no expert but I went through the FASTER study done by Jeff Volek and the blood ketone levels from the graphs there are a lot lower then I suspected.
      My own levels rarely are above 0.5mmol/l in the morning and I am on a low carb diet for years after being on a paleo diet for 5 years before.
      Keto-adaptation is not the same as in ketosis. Being keto-adapted means you can burn fat like a boss while not strictly in nutritional ketosis.

    • Flora

      HI Peter:

      According to your artical ,you took some preparations of exogenous ketones, like BHB monoester, AcAc di-ester , BHB mineral salt
      1. May I ask where can I buy those exogenous ketones?
      2. Which brand can produce higher ketone level?
      Since I adopt keto diet three months ago; however, plenty social parties let me out ketogenesis all the time
      Recently, I discover that ketone esters can increase brown fat, beginning searching relative information.

      truly hoping you can tell me where to buy those ketone esters

      I have tried the following preparations of exogenous ketones: BHB monoester, AcAc di-ester, BHB mineral salt (BHB combined with Na+, K+, and Ca2+). I have consumed these at different concentrations and in combination with different mixing agents, including MCT oil, pure caprylic acid (C8), branch-chained amino acids, and lemon juice (to lower the pH). I won’t go into the details of each, though, for the sake of time.

      • At the time I did this they were not for sale ad I was using specific formulations prepared for research use. Today, one can easily obtain BHB salts (Ca, Na, Mg), but not sure if the ester or AcAc diester are commercially available. I think the salts are plenty good. Prototype Nutrition sells them.

  • Arnie

    Hello Peter,

    I must admit; this has been a remarkable journey for me and my wife. We started with Nutritional Ketosis July 2015, lost weight AND gained muscle (we train compound and weight training 2-3 times a week (2hrs) starting with 20 min of HIT).

    We have grown and our body has completely changed where we can see muscle definitions like never before and we have been training since 2003 (with some intervals 🙂 ). These past 6 months have been really a game changer.

    Overtime we tried everything from: Body for Life, reducing refined sugar intake, substituting to complex, non-refined and low glycemic carbohydrates, increasing protein intake, calorie reduction and always reducing the fat content in our food intake.

    With this new lifestyle we are able to control weight, reduce appetite and cravings (esp. during our business travel), enhance our performance in the gym and increase muscle while reducing our subcutaneous fat.
    Thank you for your material and thorough investigations. It helped us a lot in our quest to a healthier body and lifestyle and we are still looking to increase performance and optimize our physique, ready to take the next step to exogenous ketones.

  • Rawnaq

    Hi Dr. Attia,

    Will water fasting for 3-10 days speed up the process of the body becoming fat-adapted? (Have you read the study that water fasting for 2-5 days causes autophagy, and refeeding after that period triggers stem cell regeneration? So water fasting should kill the cells with carb-reliant mitochondria, and the stem cell regeneration when refeeding while doing keto should cause birth of cells that are fat-adapted?)


    • Yes, basically anything that materially reduces insulin AUC will increase fat adaptation. Nothing does that faster than starvation.

  • Jeff

    Peter, I am confused by the NuSI website, where you are no longer listed as President of NuSI – it lists Chris Ochner as President. And there is no mention of you from the Leadership link at the top. Is it possible you have left NuSI? If so what are you up to these days? Or if not – you should let them know they need to fix their pages. Thanks!

    • That is correct. I left NuSI at the end of the December. I am focusing my time on my medical practice and a few other things.

    • Evelyn Wong

      “Body weight is determined by calories in, calories out; how much you eat and drink versus the calories that we expend.”

      Chris Ochner, CBS This Morning, 1/23/14

      DEAR GOD NO!!!!!!!!!!!!!!!!!!!!!

  • Dr. Jason Fung

    Peter – fasting is not starvation. One is voluntary the other is not. Like saying bulimia is the same as projectile vomiting

    • David

      I believe Dr. Attia was being facetious here in order to illustrate a point 🙂

  • Ali

    Dr. Attia,

    Do you intend to share the details of your departure from NuSI at any point? I understand, if you’d rather not.


  • David

    Hmmm, well if we aren’t going to be privy to what went down hopefully we can at least benefit from more frequent blog posts 🙂

  • Dez Cato


    What are a couple books I could read to gain a full understanding of ketones and how they work in the body?


  • Frank

    Is this ester from Dr. Veech? Is it the same ester discussed in this new article on him: http://theamericangenius.com/business-news/ketone-ester-fuel-treats-diseases/

  • Scott Goyette


    I am a motivational speaker and part time athlete. I am all about finding ways to increase my energy and focus. I have recently tried a product, Keto OS exogenous ketones and it has been helpful. I would be interested in how you feel I should ingest ketones and what possible side effects there might be in the future. So far, so good for me, but I want to make sure I am doing the right thing. Is there anything you would suggest doing along side BHB salts for enhanced energy and focus?

    Scott Goyette

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  • brent

    Hi Peter / Dom, are either of you familiar with the product KetoForce or Patrick Arnold? The manufacture claims, subtly, that they synthesized the original ketone esters for Dom’s research. Although he doesn’t use your name, its obvious to anyone familiar with your work.

    His store:

    • Walter

      Dom knows Patrick Arnold. Listen to the Tim Ferriss Patrick Arnold podcast at about 105 minutes in for an answer to your question.

  • Steve Stephenson

    My 3/2/2016 PET bone scan shows a recurrent prostate cancer tumor and 3 bone metastases sites of my aggressive prostate cancer (T3N1 Gleason 10).

    Despite having had external radiation (and hormone) therapy 4 years ago, my radiation oncologist says I did not experience radionecrosis (delayed radiation injury) so I’m not approved for Hyperbaric Oxygen Therapy by US Food and Drug Administration (FDA),

    In https://youtu.be/yWRnma8Tet0?t=38m38s Dom showed that ketones, even in presence of glucose, increases cancer cell death and decreases cancer cell proliferation.

    I’ve proved to myself that I am following a ketogenic diet by putting my diabetes in remission (A1C 6.9 to 5.5) and losing 30 lbs and 6 inches on belt (BMI 31.4 to 27). I try to do no carbs, but do have a salad and a serving of very low glycemic vegetables (<20g / day).

    So I'd like to boost the ketones from my diet by adding exogenous ketones like in this post; hoping to slow my cancer's progression.

    What should I add and how much? Where do I get them? Are they affordable?


    • Frank

      Have you added mct c8 in the am? Start with that. Only test with a blood meter.

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  • Lynda

    i have a lot to add to this, my child has a fatty oxidation disease, in essence he cant eat fat or protein as his body cannot break them down. He has been on artificial ketones since 6 months of age which saved his life as he was dying. The ketones provide the energy for his brain and other vital body organs – he doesn’t produce any ketones at all so supplementation is essential. I also was an endurance athlete and right from the start I decided to go into fat adaptation as my training tool (not carb loading), being in ketosis for my long distance tri training was amazing, I felt fabulous and was able to train daily. The fat adaptation method is still very new for athletes, but for me made a lot of sense, and i had a very good grasp on ketones and ketosis. I do have a medical supply of DL Hydroxybutyric Acid that is for my child, I have sometimes thought i should be taking it too, but the supply I have is heavily monitored. I know it would give me huge advantages in energy, as this is what is keeping my child alive.

  • Doug

    Peter, We started on the Keto eating this week and all going well. I got some KetoSport Ketoforce which is an exogenous ketone salt. What would be good times to take this?
    I am thinking that this was suggested to me since we are just starting out to help us over the rough spots. But we have not had any yet.

  • Jack

    Dr. Peter,

    I am a student at university, and am currently in the process of writing a proposal for an independent study on exogenous ketone supplementation and the effect it has on oxygen consumption. I would value your feedback and take into great consideration any suggestions you may have as to how to conduct this research.

    Thank you for your consideration,

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  • Chris Budka

    Peter- thanks for all your efforts here. You spoke of ketonuria above. How can I measure the efficiency of my ketone utilization. For example: if I test using urine samples and I am getting a higher reading of ketones in the urine, does that indicate I am in Ketosis, or, I am just flushing the ketones out and not using them for fat oxidation? I find I am in the darker pink range until I take MCTs. Then, the reading goes to purple. Any info is appreciated.

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  • Travis Denson

    Hey Peter- You wrote in this post that “A very close friend of mine is contemplating a run at the 24 hour world record (cycling). I think it’s likely we’ll be able to get him to 2 g/min of fat oxidation on the correct diet.” … so 1) Did your friend set the record? and 2) Were you able to get him to 2 g/min?

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  • Hi Peter

    Thank you for all your effort and all the great information. I was researching for a paper I am currently working on and cound’t find a definite answer to the question – how much ATP per mol BHB is actually produced?

    Cheers Jula

  • Misty

    I have a quick question about exogenous ketones. When you take exogenous ketones and eat carbs what does your body do with the carbohydrates in your system? Does it cause elevated blood glucose because your body is not using that as your source of energy?

  • Owen

    Can you do high intensity interval training (HIIT) and get good results in a ketogenic state? I’ve been low carb for about a year and ketogenic for the past 5-6 months.

  • Mark

    When a person takes exogenous ketones, do the body stop or reduce the amount of ketones it produces? And, if a person regularly supplements with exogenous ketones, would the body take time to resume normal production levels, similar to the way brain chemical production is reduced in people who abuse drugs? Thanks!

  • Louis Malinow

    I take care of several athlete “extremists” who, despite having very lean bodies, have elevation of A1C and even fasting glucose. Insulin is often in the 5 to 10 range…….higher than I’d expect for an elite athlete with extreme insulin sensitivity. My question is: Can “over” exercising lead to a degree of insulin resistance. In the ketotic state….or exogenously provided ketones……I see the glucose fall during exercise…..but in the carb loaders who aren’t fat adapted……I’m guessing glucose production during exercise (some of these guys ride at an average wattage of 230-250 for hours) exceeds uptake?

  • Roger Gustafson

    Hi Peter,
    After seeing my MD lose 60 lbs on the IdealProtein diet in 4 months (LCLFModP Ketogenic), I started the program, and have lost 13 lbs in 2 weeks. Easy and enjoyable. I use a Ketonix Sport daily and typically show 7-Green with a few days of 5-Yellow mixed in. I used KetoCaNa (Amazon) one morning before heading to the gym and the Ketonix flashed Red showing high traces of ketones. I felt an increase in energy and clarity throughout the day even on just a half serving. I can attest to the efficacy of using exogenous ketones for added energy, and I wonder if it will help me get fat-adapted quicker. Unsure if I will use KetoCaNa regularly, or just before workouts, or not at all until I hit my target weight.
    Thanks for all your research and writing. I really appreciate learning from you in this exciting field.

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  • D.J.

    Hey Peter,

    I was wondering if you had any thoughts about the most recent NuSI study that was headed by Kevin Hall. Thanks.

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  • Hi Peter,
    Thanks for using yourself as a guinea pig and thereby creating radials for future explorations.

    My friend introduced exogenous ketones to me and I just started googling and yours is the first article that came up. Suuuuper interesting! I love exercising but you’d never know it to look at me. I wish my body would burn the calories rather than storing them and leaving me tired and hungry. I’m less concerned about my appearances than I am about not having energy and the increasing load the extra weight puts on my system. However I do notice that, not only for myself, I never met a weight loss regime that didn’t have the tendency messing with my energy levels and with the end result of developing a more efficient metabolic system i.e. being larger than before a couple years later.

    If you have any recommendations for websites that are aimed at newbies like me, I’d appreciate the link.

    I like your writing clarity and will check out the rest of your site.


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  • Wesley

    My daughter did the ketosis diet and had remarkable results. As with anything that works, the supplement and MLM folks were soon to follow. So I have friends pushing various ingestible “ketones” products. Are those similar to what you were taking, and can breaking down food into micro-nutrients really work?

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  • Larry Hemm

    I had Chronic Obstructive Pulmonary Disease (COPD) for 7 years, My first symptoms were dry cough, chest tightness and shortness of breath. This was ongoing for 3 years, my first chest x-ray only showed bronchitis. Finally I went to a pulmonologist and was diagnosed with COPD, I was immediately placed on Seebri Breezhaler, it’s an inhalation powder, I take it once a day in the morning. Finally, i started on COPD Herbal Formula i ordered from NewLife Herbal Clinic, the herbal formula worked 10x better than all the medications my pulmonologist had prescribed. I have had a total decline of symptoms since i started on this herbal formula, visit www .newlifeherbalclinic .com or email info@ newlifeherbalclinic. com

    Larry HEMM

  • Larry Hemm

    I had Chronic Obstructive Pulmonary Disease (COPD) for 7 years, My first symptoms were dry cough, chest tightness and shortness of breath. This was ongoing for 3 years, my first chest x-ray only showed bronchitis. Finally I went to a pulmonologist and was diagnosed with COPD, I was immediately placed on Seebri Breezhaler, it’s an inhalation powder, I take it once a day in the morning. Finally, i started on COPD Herbal Formula i ordered from NewLife Herbal Clinic, the herbal formula worked 10x better than all the medications my pulmonologist had prescribed. I have had a total decline of symptoms since i started on this herbal formula, visit www .newlifeherbalclinic .com or email info@ newlifeherbalclinic. com

    Larry HEMM

  • Joe

    I’ve been on a keto diet for quite some time for weigh loss purposes.
    I was looking in to possible weigh loss benefits of exogenous ketone supplements.
    I hadn’t really delved too far in to the science of this and your article and self-experiment are quite fascinating and appear to be far more controlled than typical home-brew experiments. Further study under more rigorous conditions is warranted.
    One interesting use of this could be as it applies to space science/travel: Oxygen is expensive to lift in to orbit and not terribly efficient to recycle. The less oxygen used by space travelers, the better. Could a ketone-rich diet help astronauts use less oxygen?

  • Peter et al….

    Has anyone experienced or heard of anyone having heart problems leading to seizure, collapse, heart attack, and/or cardiac arrest they could trace to an overdose of Exogenous Ketones?

    I believe I overdosed on KetoCana (perhaps as much double the standard dose) as I was finishing up the remainder of my supply I had bought from a friend who had previously purchased the KetoCana. This would not likely have been a simple averse reaction as I had been experimenting/using Exogenous Ketones (including KetoCana, Keto/OS, etc) for a couple months already (less than 10 times though total).

    My story is that on May 20th I may have double dosed on the KetoCana, when I took it in between a double work shift I was doing that day/night. My food intake was low and I was doing an intermittent fast but that was a regular thing for me. However, I apparently came through the 2nd shift with more energy than normal as a girlfriend I was with later that night commented about. Also I acted sassier than normal, not sure if that’s a symptom or I simply had extra energy and chose to use it that way.

    The next morning (after very little sleep) I woke up to attend a martial arts class and behaved strangely when I arrived, not talking to or greeting other students or the master/shifu (not normal behavior for me) and I began a slow jogging warmup. Apparently after less than a single lap around a small gym, I headed towards the other room and bumped into a plant and collapsed (possibly having a seizure), my heart got up to 200 beats/minute and then stopped. I was given CPR for 10 minutes, ambulance arrived and shocked me twice, I was cooled and put in coma at hospital and came out of it a few days later amazingly with no apparent brain damage (except acute memory loss extending from the day I took the Ketones (day before collapse) to the day after I woke from the coma. Apart from that, it’s been over 3 weeks since my release from cardiac care unit and my memory is as sharp as ever (minus the incident and the timeframe mentioned before which is completely blank still). My other cognitive abilities seem normal as well. On one hand I think all my Keto-type eating, C8, Coconut Oil, and Exogenous Ketones may be responsible for protecting my brain and on the other hand I can’t think of any other reason the heart attack could have been triggered unless it was simply long term lack of sleep but that’s nothing new for me. I’m 40 years old and have been an active athlete all my life and this is the first heart-related incident I can recall ever having. Anybody think it could have been overdosing on Exogenous Ketones (KetoCana)?

    PS>..I was also taking lots of other supplements like Rhodiola, Maca, Matcha green tea but from my containers from that day it didn’t look like I’d had time to consume much of anything yet that morning and no I didn’t consume any ketones that morning either. Just the afternoon before. Could they even still have been in my system to cause a heart problem??

    Anyone that has any thoughts they are much appreciated as I work to figure out what happened and try to determine if it’s safe for me to bring back ketones into my diet after this incident. Thanks again!


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  • Bill Wightman


    I have had the same low glucose after endurance exercise. After a 70 mile group ride here in hot Houston summer, drinking water with ketone salts, my glucose was 67 mg/dL and Ketones were 2.2 mmol/L with plenty of energy and no mental fog or nausea. I do not recall the quantity of BHB consumed but it was minimal (say at half recommended). The fun part is that I punched out a killer sprint off the front (of a modest 20 mph group) and I was holding 30 mph all alone (I’m complaining, not bragging…) for 10-15 seconds until I thought “this has to be bad for me” and slowed down. So perhaps this was the 5% improvement in O2 utilization suggested (felt like more than that). It might also be the awesome job of cleaning and lubing I did on my chain the night before. So usually a “redline” like that messes up the rest of the ride. Not in this case. The unflavored ketone water tastes pretty good when you are thirsty, not so much sipping it all day long.

    FYI this is a paper linking exogenous BHB as a possible “longevity in a pill” candidate (makes me think of the glucose suppression aspect):


    Cheers and keep your eyes wide open on the road.

  • Beth Gregg Maharaj

    question 1: are you saying that using exogenous BHB’s versus endogenously induced ketosis will not promote body fat burning? (from a long time low carber who would like to try cheating…)
    Question 2: son has CTE from a severe TBI & symptoms improve dramatically on MCT’s & ex BHB’s, Any research on this application? only see stuff for AD

  • Linda Rodriguez

    I’ve got a business Ph.D. and I used to be a certified fitness instructor. Most every semester my ethics class does the Lance Armstrong Harvard Case Study. The athletes and the exercise sports science people puzzle over Lance’s supposedly greater V02 Max reported as part of the case. After seeing this ‘experiment’ I wonder if Lance didn’t have better ketone availability? Should that even be a question? It’s a rhetorical question in the end, the real question lies in whether or not Lance believed he was cheating…clearly no.


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