January 1, 2013


Ketosis – advantaged or misunderstood state? (Part II)

by Peter Attia

Read Time 12 minutes

When I wrote part I of this post, I naively assumed this would only be a two-part series. However, so many great questions and comments emerged from the discussion that I realize it’s worth spending much more time on this important and misunderstood topic. In terms of setting expectations, I suspect this series will require at least four parts.

So, back to the topic at hand…. (You may want to read or maybe reread part I for a biochemistry refresher before diving into part II.)

Is there a “metabolic advantage” to being in ketosis?

Few topics in the nutrition blogosphere generate so much vitriolic rhetoric as this one, and for reasons I can’t understand. I do suspect part of the issue is that folks don’t understand the actual question. I’ve used the term “metabolic advantage” because that’s so often what folks write, but I’m not sure it has a uniform meaning, which may be part of the debate. I think what folks mean when they argue about this topic is fat partitioning, but that’s my guess. To clarify the macro question, I’ve broken the question down into more well-defined chunks.

Does ketosis increase energy expenditure?

I am pretty sure when the average person argues for or against ketosis having a “metabolic advantage” what they are really arguing is whether or not, calorie-for-calorie, a person in ketosis has a higher resting energy expenditure. In other words, does a person in ketosis expend more energy than a person not in ketosis because of the caloric composition of what they consume/ingest?

Let me save you a lot of time and concern by offering you the answer: The question has not been addressed sufficiently in a properly controlled trial and, at best, we can look to lesser controlled trials and clinical observations to a make a best guess. Believe me, I’ve read every one of the studies on both sides of the argument, especially on the ‘no’ side, including this one by Barry Sears from which everyone in the ‘no’ camp likes to quote. This particular study sought to compare a non-ketogenic low carb (NLC) diet to a ketogenic low carb (KLC) diet (yes, saying ‘ketogenic’ and ‘low carb’ is a tautology in this context). Table 3 in this paper tells you all you need to know. Despite the study participants having food provided, the KLC group was not actually in ketosis as evidenced by their B-OHB levels. At 2-weeks (of a 6-week study) they were flirting with ketosis (B-OHB levels were 0.722 mM), but by the end of the study they were at 0.333 mM. While the difference between the two groups along this metric was statistically significant, it was clinically insignificant. That said, both groups did experience an increase in REE: about 86 kcal/day in the NLC group and about 139 kcal/day in the KCL group (this is calculated using the data in Table 3 and Table 2). These changes represented a significant increase from baseline but not from each other. In other words, this study only showed that reducing carbohydrate intake increased TEE but did not settle the ‘dose-response’ question.

This study by Sears et al. is a representative study and underscores the biggest problems with addressing this question:

  1. Dietary prescription (or adherence), and
  2. Ability to accurately measure differences in REE (or TEE).

Recall from a previous post, where I discuss the recent JAMA paper by David Ludwig and colleagues, I explain in detail that TEE = REE + TEF + AEE.

Measuring TEE is ideally done using doubly-labeled water or using a metabolic chamber, and the metabolic chamber is by far the more accurate way.  A metabolic chamber is a room, typically about 30,000 liters in volume, with very sensitive devices to measure VO2 and VCO2 (oxygen consumed and carbon dioxide produced) to allow for what is known as indirect calorimetry.  The reason this method is indirect is that it calculates energy expenditure indirectly from oxygen consumption and carbon dioxide production rather than directly via heat production.  By comparison, when scientists need to calculate the energy content of food (which they do for such studies), the food is combusted in a bomb calorimeter and heat production is measured.  This is referred to as direct calorimetry.

Subjects being evaluated in such studies will typically be housed in a metabolic ward (don’t confuse a metabolic ward with a metabolic chamber; the ward is simply a fancy hospital unit; the chamber is where the measurements are made) under strict supervision and every few days will spend an entire 24 hour period in one such chamber in complete isolation (so no other consumption of oxygen or production of carbon dioxide will interfere with the measurement).  This is the ‘gold standard’ for measuring TEE, and shy of doing this it’s very difficult to measure differences within about 300 kcal/day.

Not surprisingly, virtually no studies use metabolic chambers and instead rely on short-term measurement of REE as a proxy.  In fact, there are only about 14 metabolic chambers in the United States.

A broader question, which overlays this one, is whether any change in macronutrients impacts TEE.

Despite the limitations we allude to in the summary of this review, there is a growing body of recent literature (for example this studythis study, and this study) that do suggest a thermogenic effect, specifically, of a ketogenic diet, possibly through fibroblast growth factor-21 (FGF21) which increases with B-OHB production by the liver.

These mice studies (of course, what is true in mice isn’t necessarily true in humans, but it’s much easier to measure in mice) show that FGF21 expression in the liver is under the control of the transcription factor peroxisome proliferator-activated receptor a (PPARa), which is activated during starvation. Increased FGF21 promotes lipolysis in adipose tissue and the release of fatty acids into the circulation. Fatty acids are then taken up by the liver and converted into ketone bodies. FGF21 expression in liver and adipose tissue is increased not only by fasting but also by a high fat diet as well as in genetic obesity which, according to these studies, may indicate that increased FGF21 expression may be protective. Hence, ketosis may increase TEE either by increasing REE (thermogenic) or AEE (the ketogenic mice move more).  Of course, this does not say why. Is the ketogenic diet, by maximally reducing insulin levels, maximally increasing lipolysis (which dissipates energy via thermogenic and/or activity ‘sinks’) or is the ketogenic diet via some other mechanism increasing thermogenesis and activity, and the increased lipolysis is simply the result?  We don’t actually know yet.

Bottom line: There is sufficient clinical evidence to suggest that carbohydrate restriction may increase TEE in subjects, though there is great variability across studies (likely due the morass of poorly designed and executed studies which dilute the pool of studies coupled with the technical difficulties in measuring such changes) andwithin subjects (look at the energy expenditure charts in this post).  The bigger question is if ketosis does so to a greater extent than would be expected/predicted based on just the further reduction in carbohydrate content. In other words, is there something “special” about ketosis that increases TEE beyond the dose effect of carbohydrate removal?  That study has not been done properly, yet.  However, I have it on very good authority that such a study is in the works, and we should have an answer in a few years (yes, it takes that long to do these studies properly).

Does ketosis offer a physical performance advantage?

Like the previous question this one needs to be defined correctly if we’re going to have any chance at addressing it. Many frameworks exist to define physical performance which center around speed, strength, agility, and endurance.  For clarity, let’s consider the following metrics which are easy to define and measure

  1. Aerobic capacity
  2. Anaerobic power
  3. Muscular strength
  4. Muscular endurance

There are certainly other metrics against which to evaluate physical performance (e.g., flexibility, coordination, speed), but I haven’t seen much debate around these metrics.

To cut to the chase, the answers to these questions are probably as follows:

  1. Does ketosis enhance aerobic capacity? Likely
  2. Does ketosis enhance anaerobic power? No
  3. Does ketosis enhance muscular strength? Unlikely
  4. Does ketosis enhance muscular endurance? Likely

Why? Like the previous question about energy expenditure, addressing this question requires defining it correctly.  The cleanest way to define this question, in my mind, is through the lens of substrate use, oxygen consumption, and mechanical work.

But this is tough to do! In fact, to do so cleanly requires a model where the relationship between these variables is clearly defined.  Fortunately, one such model does exist: animal hearts.  (Human hearts would work too, but we’re not about to subject humans to these experiments.)  Several studies, such as this, this, and this, have described these techniques in all of their glorious complexities.  To fully explain the mathematics is beyond the scope of this post, and not really necessary to understand the point.  To illustrate this body of literature, I’ll use this article by Yashihiro Kashiwaya et al.

The heart is studied because the work action is (relatively) simple to measure: cardiac output, which is the product of stroke volume (how much blood the heart pumps out per beat) and heart rate (how many times the heart beats per minute).  One can also measure oxygen consumption, all intermediate metabolites, and then calculate cardiac efficiency.  Efficiency increases as work increases relative to oxygen consumption.

Before we jump into the data, you’ll need to recall two important pieces of physiology to “get” this concept: the acute (vs. chronic) metabolic effect of insulin, and the way ketone bodies enter the Krebs Cycle.

The acute metabolic effects of insulin are as follows:

  1. Insulin promotes translocation (movement from inside the cell to the cell membrane) of GLUT4 transporters, which facilitate the flux of glucose from the plasma into the inside of the cell.
  2. Insulin drives the accumulation of glycogen in muscle and liver cells, when there is capacity to do so.
  3. Least known by most, insulin stimulates the activity of pyruvate dehydrogenase (PDH) inside the mitochondria, thereby increasing the conversion of pyruvate to acetyl CoA (see figure below).
Image credit: Veech et al., 2001

The second important point to recall is that ketone bodies bypass this process (i.e., glucose to pyruvate to acetyl CoA), as B-OHB enters the mitochondria, converts into acetoacetate, and enters the Krebs Cycle directly (between succinyl CoA and succinate, for any biochem wonks out there).  I keep alluding to this distinction for a reason that will become clear shortly.

An elegant way to test the relative impact of glucose, insulin, and B-OHB on muscular efficiency is to “treat” a perfused rat heart under the following four conditions:

  1. Glucose alone (G)
  2. Glucose + insulin (GI)
  3. Glucose + B-OHB (GK)
  4. Glucose + insulin + B-OHB (GIK)

In fact, that’s exactly what this paper did.  Look at what they found:

Image credit: Kashiwaya et al., 1997

The upper two graphs in this figure show similar information, namely the response of cardiac output and hydraulic work to each treatment. (Cardiac output is pure measurement, as I described above, of volume of blood displaced per unit time. Hydraulic work is a bit more nuanced; it measures the mechanical work being done by the fluid.)

Adding insulin to a fixed glucose (GI) load increases both cardiac output and hydraulic work, but it’s only significant in the case of hydraulic work.  Conversely, adding B-OHB to glucose (GK) increases both cardiac output and hydraulic work significantly. Interestingly, combining insulin and B-OHB with glucose (GIK) increases neither.

Oxygen consumption was significantly reduced in all arms relative to glucose alone, so we expect the cardiac efficiency to be much higher in all states. (Why?  Because for less oxygen consumption, the hearts were able to deliver greater cardiac output and accomplish greater hydraulic work.)

The figure on the bottom right shows this exactly.  If you’re wondering why the gain in efficiency is so great (24-37%), the answer is not evident from this figure.  To understand exactly how and why adding high amounts of insulin (50 uU/mL) or B-OHB (4 mM) to glucose (10 mM) could cause such a step-function increase in cardiac efficiency, you need to look specifically at how the concentration of metabolic intermediates (e.g., ATP, ADP, lactate) varied in the rat heart cells.

This is where this post goes from “kind of technical” to “really technical.”

The figure below presents the results from this analysis.  The height of the bar shows the fold-increase for each of the three treatments relative to glucose alone.  To orient you, let’s look at a few examples.  In the upper left of the figure you’ll note that GI and GIK both significantly increase glucose concentration in the cell, while GK does not.  Why?  The GI and GIK treatments both increase the number of GLUT4 transporters translocated to the cell surface so more glucose can flux in.  GK does increase glucose concentration, but not significantly (in the statistical sense).

Image credit: Kashiwaya et al., 1997

Table 1 from this paper, below, summarizes the important changes from this analysis.  In particular, look at the last column, the Delta G of ATP hydrolysis.

I was really hoping to write this post without ever having to explain Delta G, but alas, I’ve decided to do it for two reasons:

  1. To really “get” this concept, we can’t avoid it, and;
  2. The readers of this blog are smart enough to handle this concept.
Image credit: Kashiwaya et al., 1997

Delta G, or Gibbs free energy, is the “free” (though a better term is probably “available” or “potential”) energy of a system.

Delta G = Delta H – Temperature * Delta S, where H is enthalpy and S is entropy. The more negative Delta G is, the more available (or potential or “free”) energy exists in the system (e.g., a Delta G of -1000 kcal/mol has more available energy than one of -500 kcal/mol). To help with the point I really want to make I refer to you this video which does a good job explaining Gibbs free energy in the context of a biologic system. Take a moment to watch this video, if you’re not already intimately familiar with this concept.

Now that you understand Delta G, you will appreciate the significance of the table above.  The Gibbs free energy of the GI, GK, and GIK states are all more negative than that of just glucose. In other words, these interventions offer more potential energy (with less oxygen consumption, don’t forget, which is the really amazing part).

To see what the substrate-by-substrate changes look like across the mitochondria and ETC, look at this figure:

Image credit: Kashiwaya et al., 1997

Though it is by no means remotely obvious, what is happening above boils down to two major shifts in substrate utilization:Though it is by no means remotely obvious, what is happening above boils down to two major shifts in substrate utilization:

  1. In one step the reactants NADH/NAD+ become more reduced (in the chemical sense), and;
  2. In another step the reactants CoQ/CoQH2 become more oxidized (in the chemical sense).

These changes, taken together, widen the energetic gap between the states and, in turn, translates to a higher (i.e., more negative) Delta G which translates to greater ATP production per unit of carbon. 

Additional work, which you’ll be delighted to know I will not detail here, in fact shows that on a per carbon basis, B-OHB generates more ATP per 2-carbon moiety than glucose or pyruvate.  As an aside, this phenomenon was first described in 1945 by the late Henry Lardy, who observed that sperm motility increased in the presence of B-OHB (relative to glucose) while oxygen consumption decreased!

Is there a reason to prefer GK over GI?

Yes. Recall that ketones make their way onto the metabolic playing field without going through PDH.  Adding more insulin to the equation forces more pyruvate towards PDH into acetyl CoA.  While B-OHB “mimics” the effect of additional insulin, it does so in a much cleaner fashion without the complex cascade of events brought on by additional insulin (e.g., decreased lipolysis) and, perhaps most importantly, avoids the logjam of impaired PDH due to insulin resistance (I’ll come back to this point in a future post when I address Alzheimer’s disease and Parkinson’s disease).  In essence, B-OHB “hijacks” the Krebs Cycle via a slick trick that lets it bypass the bottleneck, PDH.  All the glucose and insulin in the world can’t overcome this bottleneck.  It’s truly a privileged state and a remarkable evolutionary trick that we can utilize B-OHB.

Back to the original question…

Clearly, in the highly controlled setting of a perfused rat heart, ketones offer an enormous thermodynamic advantage (28%!).  But what about in aggregate human performance?  There is no reason to believe that therapeutic levels of B-OHB (either through nutritional ketosis or by ingesting ketone esters) would increase anaerobic power, since the anaerobic system does not leverage the Delta G improvement I’ve outlined here.  Same is true for muscular strength.  However, there is reason to believe that aerobic capacity and muscular endurance could be improved with sufficient B-OHB present to compliment glucose.

It turns out this has been demonstrated repeatedly in subjects ingesting ketone esters, developed by Dr. Richard Veech (NIH) and Dr. Kieran Clarke (Oxford). Because the results of their work have not yet been published, I can’t comment much or share the data I have, which they shared with me.  I can say the ingestion of B-OHB in the D-isoform (the physiologic isoform), resulting in serum levels between 4 and 6 mM, did lead to significant increases in aerobic power and efficiency in several groups of elite athletes (e.g., Olympians) across multiple physical tasks maximally stressing the aerobic system.

Once published, I believe these studies will be a real shot across the bow of how we view athletic performance.  It is very important to point out, however, that these studies don’t exactly address the most relevant question, which has to do with nutritional ketosis.  In other words, ingesting ketone esters to a level of 4 to 6 mM might not be the same as de novo producing B-OHB to those levels.  But, such trials should be forthcoming in the next few years.  Personally, I am most eager to see the results of a ketone ester alone versus nutritional ketosis versus combination treatment, all to the same serum level of B-OHB.

The Hall Paradox

For the really astute readers, you may be saying, “Waaaaaaaait a minute, Peter…if ketones increase Gibbs free energy while reducing oxygen consumption, should this imply TEE goes down?”  You’re right to ask this question.  It was the first question I asked when I fully digested this material.  If each molecule of B-OHB gives your muscles more ATP for less oxygen, you should expend less not more energy at the same caloric intake, right?

I was discussing this with Kevin Hall at NIH, an expert in metabolism and endocrinology.  Kevin pointed out the error in my logic.  I failed (in my question) to account for the energetic cost of making the ketones out of fat.  Remember, in the experiments described above, the B-OHB is being provided for “free.”  But physiologically (i.e., in nutritional ketosis or even starvation), we have to make the B-OHB out of fat.  The net energy cost of doing this is actually great. According to Kevin, it is not generally appreciated how making ketones from fatty acids affects overall energy efficiency. Nevertheless, this can be examined by comparing the enthalpy of combustion of 4.5 moles of B-OHB, which is about -2,192 kcal, with the enthalpy of combustion of 1 mole of stearic acid (about -2,710 kcal) that was used to produce the 4.5 moles of ketones. Thus, there is about 20% energy loss in this process.  Hence, the energy gain provided by the ketones is actually less than the energy cost of making them, at least in theory.

This suggests that being in nutritional ketosis may require more overall system energy, while still increasing work potential.  In other words, a person in nutritional ketosis may increase their overall energy expenditure, while at the same time increasing their muscular efficiency.  In honor of Kevin, I refer to this as the Hall Paradox.

Parting shot

Ok, if you’re still reading this, give yourself a pat on the back.  This was a bit of chemistry tour de force.  Why did I do it? Well, frankly, I’m tired of reading so much nonsense on this topic. Everybody with a WordPress account (and countless people without) feels entitled to spew their opinions about ketosis without even the slightest clue of what they are talking about.  As I said in part I of this series, there is no bumper sticker way to address this question, so to say ketosis is “good” or “bad” without getting into the details is as useful as a warm bucket of hamster vomit (unless you’re Daniel Tosh, in which case I bet you can find a great use for it).

Next time, I’ll try to back it out of the weeds and get to more clinically interesting stuff.  But we had to do this and we’re better for it.

Chemistry by Marcin Wichary is licensed under CC by 2.0

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  • I just made the suggestion that a ketogenic diet might plausibly enhance muscular growth as well as recovery (http://www.ketotic.org/2012/12/bcaas-and-keto-diets.html). I’d be interested in your thoughts about that.

    • I’ve seen data to suggest (and have experienced personally and with clients) that one can gain lean mass on a KD. The question is if there is an advantage over a non-KD. I would need to see more data on BCAA-B-OHB interaction to have an opinion.

  • I’ve heard many criticisms of ketosis as of late…probably because you’ve popularized it to a certain extent. What really annoys me, personally, is people referring to a state of ketosis as being in a state of starvation. Even when I present my own experiences of satiety, muscle maintenance, and high energy levels (not a result of starvation) when in nutritional ketosis, I get told that I must not have been in ketosis over a long period of time, if at all. In short, I don’t know what I’m doing or what I’m talking about.

    Shortly after reading your blog posts last spring, I decided to give NK a try. I did this along with IF. I had planned to do IF all along, and I decided to both together for maximum results. I would eat my first meal at 11 or 12 and my last one at 8-9 at night. I did short fasts. Because I didn’t want to put too much stress on my body at once, I didn’t exercise for the first two weeks (I went 13 days). I do sprints on the regular basis, and when I did my first sprint on Ketosis I noticed that I was a lot slower. I’d read that you could lose a little power, but I had lost a considerable amount of top end speed. But after a few sprints I realized that I was hardly even breathing hard. I never run long distance, but I got the urge to start running. I ran about 2 miles, averaging just over 6 minutes per mile, not lighting fast, but not a jog. I was amazed that I didn’t even really have to catch my breath afterward. This continued for the 8 weeks I was in ketosis. Not to mention that I went from about 12% body fat down to 9%.

    My evidence is merely anecdotal, but for me, ketosis definitely increased my aerobic capacity. And towards the end, I was actually regaining some top end speed.

    • Nathan, I think I can actually say I’ve also regained most of what I lost at the very top end. But my comfort level at 60-70% VO2 max is getting greater and greater each month.

    • Hemming

      My experience has been exactly the same. I’m starting to regain speed and muscle strength after an initial drop.

      Did you supplement with magnesium? After I’ve started sprinting a couple of times per week again I’m often getting cramps in my calfs even though I’m supplementing with magnesium 3-4 times per week. Did you ever experience that?

    • Hemming,

      I did not supplement with magnesium. The cramps may have been due to a lack of potassium. Potassium actually works within the cells, and if it is absent it can cause cramping. Ironically, a lack of sodium can cause ones lack of potassium, as the body will often ditch potassium to hold on to sodium. If the cramps occurred during your sprints, I’d up your potassium intake a bit the next time. Also, make sure you get enough sodium, your kidneys don’t hold on to sodium as well when you go low carb, and NK is as low as it gets. I ate a lot of spinach when I was in NK for extra potassium. I’d also eat blueberries and raspberries directly after workouts, about a cup. Cheese and nuts were my other ubiquitous sources of potassium. I did drink about a gram of bullion most days, and two or three on days when I lifted weights to avoid hypotension (light headedness). I also salted my foods quite a bit.

      Did the cramps occur during running, or after?

    • Hemming

      Hi Nathan,

      Thank you for sharing your experiences.

      My cramps happen at night. A few times I’ve woken up at night to go to the bathroom (i.e. not because of the cramps) but my calfs were cramped to a point where I could almost not walk. My main problem is that it feels that my calfs are sore or cramping all the time. It has been like this for a prolonged period and to an extent where I often feel ‘discouraged’ to get and walk because of the feeling in my legs. I’ve tried supplementing with magnesium and recently cold showers, both seem to help but not enough. I haven’t had bad running-incuded cramps but I’ve felt it from the cramps/soreness that was already there. Sometimes I also experience cramps in my fingers which may be another indication that I’m deficient in the minerals.
      I add a salt consisting of 50% sodium, 40% potassium and 10% magnesium to all my meals. I have not had problems with hypotension symptoms although my blood pressure is very low (outside the recommended range).

      I might add that I’m sort of recovering from a longer period of a lot of cardio (not in NK) where I came to a point where I could not continue and my blood platelets had dropped to levels far below normal. This has most likely also caused my mineral levels to go way too low.
      Maybe I just simply need to add even more salt to my food even though I think I add quite a bit.

    • Hemming

      I forgot to mention:

      I’m contemplating it could also be related to that I’m not eating enough fat (while keeping both protein and carbs low) as I’ve lost weight (I’m currently 178cm and 110-114lbs/50-52kg) after going NK. Do you have any experience with fat intake and correlation of your performance/feeling in general? I’ve had some serious mood swings and for me there seems to a positive correlation between my mood and how much I eat. The problem is just that I don’t really have a big appetie in ketosis.

    • Hemming,

      I couldn’t run or sprint until I started wearing Vibrams, I always had a lot of pressure in the front of the legs whenever I ran… shin splint like pressure. After my first sprinting session in my Vibrams, my calves were so sore that I was walking straight legged the next day, and I couldn’t runs sprints for quite a few days. It took a few months for me to be able to sprint with not calve pain. It seems that you just need to let your calves heal up. Give yourself some time off.

      Also, you may be putting too many stressors on your body at once. Adapting to Ketosis while also trying to adapt to new forms of exercise may be too much for your body to handle. Not to mention the former stress your body was in from chronic cardio. I’d lay off the exercising for a few weeks and let your body heal. You’d probably gain a few pounds as well.

      At this point, your body is more than likely adapted to your old life style. Weighing 115 at 168cm and having troubles adapting to low carb are signs that your body is under a lot of stress. You may end up needing to take it slower and pack on a few pounds before resuming NK. However, there are some things to try first. One, as I said, take a break from exercise. I’ve found that this can especially important during ketosis. You will heal and be stronger for it. 2 weeks should be sufficient. The problems with your mood and such are more than likely a result of your transition to a low carb diet, which is only exacerbated by the moderate protein and low carb intake of NK. You should up your protein intake. It may lower ketone levels a bit, but it will help you transition. Shot for about 200 grams per day for 2 or 3 weeks. Doing this and resting for the next few weeks should yield you significant improvements. While your not exercising your body will replenish its glycogen stores and lay off the signaling for carbs. The extra protein will help heal your muscles and give your body some extra glucose without having to take in carbs. Adding protein can sound counter intuitive, and if you were fat adapted it would very likely hamper your progress, but it seems to work well for carbavores kicking the habit.

      Putting extra salt on your food is probably a good idea. The kidneys just don’t hold on to sodium as well when you’re low carb. So far as your BP is concerned, I don’t have a lot of answers, if you think it’s a problem I’d get it checked out. My guess would be that if you put on about 20 pounds, you’d see a slight rise in blood pressure.

    • Hemming

      Hi Nathan,

      Ironically, I did a sprint session yesterday which went far above expectations, only around 10% below my peak when I was not in ketosis. This is a major improvement compared to earlier sessions in ketosis.

      The other things you mention regarding shoes, reducing exercise, fat adaption etc. is already in order. Even before I started cutting carbs way down I would argue that I was metabolically flexible always running fasted in the morning. The ‘interesting’ thing about this that even after I stopped running >60km/week I continued to lose weight.
      I’ve started to keep a food log to see how much I actually eat. I think this has made me realise that I’m simply not eating enough fat to fuel my body. The problem for me is that I simply dont have the hunger to consume enough food. I know some will say keeping a log is a bad idea for someone trying to gain weight but for me it helps me in making sure I get enough food. The first couple of days I was surprised to see how little I actually eat (especially given that I’m more active than most people, not just exercise but in general). I’ll continue experimenting with my food intake, I think that’s the real issue in this. A low carb, low to medium fat diet is a way to failure.
      By the way, I’m having my blood work done with regular intervals and have a continuous dialogue with my doctor about it. Even though I’ve been off the chronic cardio for several there is no doubt that my body is still recovering – I was feeling more than awful on several accounts when I stopped that regime.

      Thank you for sharing your thoughts!

  • geo

    This was worth reading Peter especially the Gibbs Free Energy youtube vid. I will also chew on a lot of the other information until I don’t have to think much to understand it. I can now join others in saying thanks. I now understand you’re not just on a quacky trend receiving blog-cheers by many who probably don’t see your deeper disciplines in making science connect us to a world-view that we can apply daily in Ketogenics and in enduring lifestyles.

    Thanks again for your generous email replies as well. —Geo

  • LeonRover

    Many of us are glad you did not name this the Hall Effect or the Spin Hall Effect or even the Anomalous Hall Effect – tho’ I guess Anomalous and Paradoxical have quite a similar meaning . . . .

  • Pingback: Ketosis and improved Aerobic Capacity and Muscular Endurance | Mark's Daily Apple Health and Fitness Forum page()

  • Thanks for writing this post, Peter. I really appreciate the amount of researching, reading, and writing time a post such as this would take.

    I am really interested in your thoughts on the application of NK to different types of endurance athletes. As you probably well appreciate, the term “endurance athlete” is used as a bit of a cookie-cutter term, when in actual fact there is a huge variability in the types of endurance athletes. Compare a track cyclist to a Pro-tour rider, for example.

    I recently wrote and I’m of the opinion that NK might be more suited to endurance athletes who tend to sit on a fairly sustained pace – like IM/triathletes. In those keto-adapted, they are able to sit at a high aerobic pace for a lot less oxygen cost, as you described here. I’m less convinced that NK is suitable for any endurance athlete with a considerable “sprint” component to their race. Stage racers in cycling for example need to be able to throw down multiple attacks, bridges, hill crests, and still have plenty of top-end for a potential sprint finish. The reference slips my mind at present, but I have seen a breakdown of the likes of TdF stages that show athletes spend a good portion of time “aerobic” but the decisive moves within the race are very much lactate threshold and then some.

    I have seen your previous writing on how you have lost a bit off your top end, and it is interesting to see you have gained MOST of it back. Most isn’t all, and whilst the oxygen cost during the quiet sections of a race might not now be as taxing on you, I wonder how well you could compete with a rider who has a top-end which hasn’t been partially blunted by NK?

    Do you have any thoughts around the types of endurance athletes you feel are best suited to using this “tool”. Again, my feelings are that IM competitors might do well, but that track cyclists, criterium racers, and even Crossfitters doing multiple 20-30 minute “WODs” per week, are not that well-suited to using NK (though certainly with the latter group, the promise of shaving a couple of percentage body fat points off may be too tempting for them not to give it a go anyway).


    • These are great questions, Jamie. Consider, as you suggest, a rider in the TdF (minus the usual chemistry and pharmacopia). They need to be able to do it all. TT for an hour. Ride hard for 6, then finish a climb at >400 watts. You name it. There is not doubt that ketosis would enhance parts of this, but what I don’t know (assuming they make the ketones de novo — i.e., NK) is if that gains offsets any loss carb reduction elsewhere? Based on the data I have seen, exogenous ketosis (i.e., athletes ingesting ketone esters to high levels, like 6-7 mM), is a win-win. They get the benefits of ketosis without needing to sacrifice anything on the anaerobic side. So much work needs to be done here. I hate to even speculate on this.

  • KC


    I visit your site regularly as I try to reaffirm my diet choices. I have been on a diet that would be similar to your 2009 to 2010/11 before you went total ketosis. I am scheduling cholesterol panels while getting blood work for hypothyroid issues that I have. These will be my control as I venture down trying your path.
    The diet that I have been on to this point has yielded a total weight loss of abt. 80lbs, give or take depending on the day, and holiday if appropriate.
    I am a former Marine, and I have a very large frame, 22″ biceps type/football dream type. I am only 6.07′, so it is surprising when I tell people that I weighed in at 310lbs. They know I have lost weight but they are mystified when I tell them what my total weight was once was.
    My family has a history of cholesterol build up in our main arterial tracks. So 6egg Yolks and 3egg whites scares me a little bit. That being said, I truly believe you, Gary Taube, Mary Enig etc. are on the correct path. In other words I have taken the Red Pill. This happened in 2007-2008 when I decided to research the financial system because it pertained to my own personal business.
    I saw the new blog post, and all I really wanted to say is…. Keep it up. I understand exactly what you are going through. As I said, I own my own personal business that is very successful, and I hold down a W2 job doing engineering. I spend hours responding to posts on forums blogs etc. . I respect your level of dedication, and from a personal stand point I know what kind of time this takes….. I don’t care how fast you can type (despite the fact that you’re a rocket scientist:-)(NOTE: personal business is AVIONICS related), it still takes time and thought.
    I just wanted to say Thank you!

    • Thanks, KC. It does take more time than I’d like to spend, especially on posts like this. Luckily my wife is profoundly understanding and supportive, without which I’m pretty sure this blog would have shut down a year ago.

  • catherine

    Hey have you read the book we want to live? Do you have any of your saturated fats raw such as raw milk?

  • Preben

    Wow. I was actually able to comprehend this. Nutritional ketosis seems appealing. I’ve tried, but it is very difficult to adhere to such a strict diet. Even after a moderate LCHF-diet for about a year I find it very difficult to stick to the ketogenic diet for a long enough time do really enjoy the benefits.

    Are you planning a mini guide on how to actually do it, or know of a resource where I can find meal plans etc?

    • Yes, but you’ve hit on a great point. For many folks, it’s not easy…which is exactly why I want folks to understand it well enough to make an informed decision. Life is about optimizations and trade-offs.

    • greensleeves

      Not sure why everyone says this is very hard to do, unless you are doing the ultramarathon champion thing like Jonas Colting. 🙂
      I mean this most seriously. If you toss open Louis Diat’s classic “French Cooking for Americans,” which is noted for having easier recipes than Julia Child, and plug any of the classic recipes into an online system, you’ll see where they all fall on the fat scale. 😉 Just replace the potatoes with kohlrabi, turnips, or cauliflower and you’re done.

      For example, his Farmer’s Ragout made with pork neck – a very old French country recipe. This contains 2 pounds fat pork neck meat with bones, water, 1 c cream, 3 T lard, a medium onion, a leek, substitute 1 c kohlrabi or turnips for the potatoes, garlic, 1-1/2 c celery, parsley to garnish, bay leaf, 1 small carrot, salt, pepper. Stew until delicious & thicken with the cream. Serves 6. And you’re looking at 8 total g carbs per serving with 70% fat.

      It’s true some folks have to eat as much as 85% fat overall per day (think Jimmy Moore) but most people can get their blood ketones up to 1.5 easily at 70-75%, as long as they do some exercise as well (by which I don’t mean swimming to Catalina isn’t necessary, but a normal exercise class 2 or 3x a week.)

      So I continue to contend that ketosis is easily achievable by normal people who just have to “force” themselves to somehow swallow that horrible weird stuff known as “classic french country cooking.” It’s tough I know. People make this seem harder than it has to be. I don’t know why – just cook like Julia, Louis Diat or Elizabeth David. (Btw the last I measured, my blood ketones came out to 2.4. Just saying.) It’s all normal, delicious, easy peasant food that everyone loves to eat. 🙂

    • Ivan

      Yes yes, I second Preben’s comment, a mini guide to achieve NK would be nice 🙂
      Where I live, I cannot find a blood ketone meter in the market. Last week, I just had a lab check my fasting blood ketone along with my routine check up (an additional 20 dollars just for the blood ketone test), and it was a mere dissapointing 0.3 mM.
      Even though I have abolished all kind of carbs except for a very small portion of green veggies daily, I suspect that my fat intake is still not optimal, still too much protein.
      So I think that’s the problem for me. Not about adherence. But being in a third world country (Indonesia), it is hard to find food materials that are high in fat. I’m still fortunate that I can still increase my consumption of pork and bacon (even bacon here is not as fatty). But my fellow moslems will find it even harder to up their fat intake.

      So yes, a mini guide to achieve NK would be very nice indeed 🙂

      • I’m pretty sure at the rate I’m going at least one part to this series will need to be entirely devoted to the “ins and outs” of NK.

    • Martin

      Well, have you read the Low-carb Diet for Athletes by Phinney and Volek? NK is their child 🙂 and they explain both theory and practice very well.

    • greensleeves

      Hi Ivan:

      In Indonesia ketosis is soooo easy for you. It’s call coconut oil. Cook with fat lamb or fat beef and use plenty of palm or coconut oil for everything. If you struggle with knowing, start eating 75-80% of your daily calories as fat, 15% as protein, and the rest as carbs. Unless you are heavily insulin resistant, prediabetic, or massively overweight (think Jimmy Moore), you shold be successful at 75% fat if you exercise in a normal way 3x a week as well.

      But should you have struggles similar to Jimmy, then go ahead and adopt his 85% fat, 12% protein, 3% carbs. You will soon be extremely successful that way, but not everyone has to be so high end in the fat. 😀 It’s really not difficult if you look at your recipes and follow Volk’s advice: “When in doubt, eat fat.” Best wishes!

    • Ivan

      @Peter: Yaaay, thanks Peter 🙂 Really looking forward to it.

      @Martin: No I have not. I guess I have to order the book from Amazon. Thanks for the input.

      @greensleeves: Coconut Oil hmmm? Thanks for the input, I have not really look into coconut oil. I use olive oil and butter for cooking. What do you think about coconut milk?

      I’m a 36yo with DM Type 2, so yeah, I’m aiming for more into Jimmy’s percentage.

      I’m not worried about my carb intake. I’ve abolished them altogether. Now for the remaining fat and protein macro. The thing is not about the percentage, but how to achieve that percentage with the raw materials available here.

      Even grain-fed, meats are rarely fatty and tend to be on the leaner side compared to what available in first world countries. Grass-fed meat I bet will even be leaner but also impossible to find. Bacons have more red area than white. I can’t find heavy cream anywhere either. All grocery stores are selling low fat products *sigh* since nobody wants to buy high fat product, there’re simply no demands.

      I guess I have to revert to what Indonesians do best. Cooking internal organs LOL 🙂

    • Jim Small

      I’ve been in NK since September, 15 pound loss, feel pretty good, and re-starting a running program.

      Sticking to anything new requires some mental judo. There is a new book called The Willpower Instinct by Kelly McGonigal out of Stanford. There are some important thoughts in it.

      How you frame the changes is vital. If you say “don’t think about carbs, I won’t have carbs, keep me away from carbs” sooner or later you will probably crack. I see some hint of that in your “such a strict diet” comment.

      But if you say, “I want to be healthy and vigorous. Therefore I will eat bacon and eggs for breakfast, have a nice complex salad with lots of olive oil for lunch, and a steak with stir fried vegies for dinner” it really doesn’t sound so bad, does it?

      Another idea in the book is to precommit to the plan so it doesn’t take much energy to carry it out. I just know I’m going to pull out the skillet, chop up some sweet peppers and spinach, stir fry them in butter, then stir in two eggs scrambled with a tablespoon or two of cream for breakfast. The thought of pancakes or cereal just doesn’t enter my mind. I eat a big salad at the hospital cafeteria for lunch.

      Try to turn your change from an “I won’t eat carbs” to an “I will eat moderate protein, fat, and vegies.” it will be much more effective for you.

  • Outstanding explanation thank you.

    • Thank you, Danny. And thanks very much for the kind mention on your blog.

  • Hey Peter

    Another epic blog post, I need to set aside a lot of time to go through your posts, but the time is definitely worth it.

    As well as experiencing a fairly euphoric state in ketosis, I also find that I can perform endurance type activities better. I haven’t done any distance running for ages, concentrating on sprints more these days, but the other day, as a warmup for the sprint, I ran a little further than usual. I had more lightness in my step, I didn’t puff the way one usually does at the start of a warmup, and decided yto extend the run.

    It was great, felt light and fast, not the plodder I was. This is not just down to a KD, but I feel much steadier and up for a challenge eating this way. I also run some group kettlebell classes each week, and do fairly high intensity work on a ketogenic diet.

    So it works well for me.

    • Interesting to hear, Steve. I wish we had data to know why some, like you, respond well, while others do not. Are there genetic differences? Are there differences in implementation? Is it all about allowing for enough time to adapt?

    • leslie

      I too have unlimited energy on my long daily bike rides, am faster, and even push harder for longer. I go out and want to push to a heart rate of 150-172 or a speed of 20-23 miles an hour (I’m 56 years old) and stay there indefinitely. Now that I’ve been keto for 4 months I have my anaerobic push back too and can hang on in the sprints better than two months ago. Before I was tired all the time and had to work to get into a 130 heart range. This diet has freed me from fatigue completely.

      Is it the reduction in glycogen usage so it goes further and a higher percentage at all efforts is fat?

      Is it hopping off the insulin roller coaster? I had fasting glucose levels of around 100 on several annual physicals (of course with no discussion about it not being ok).

      I have hypothyroidism and feel great on this diet. My energy is perfect so I don’t think my T3 has tanked. And of course my mind is clear and mood so much more stable.

      I’ve researched Stevia though and only read it having a positive effect on blood glucose (pure extract). My glucose levels tend to be 100-115 after eating. Could stevia be affecting BG?

      What is a normal 1 and 2 hour post prandial BG level?

  • Philip S

    These posts are great! It’s so nice to see detailed analysis instead of hand-waving rhetoric. And it’s refreshing to see an honest account of what we do and do not know, and how certain or uncertain it is. Science is murky at the edges of discovery, and I like to get a feel for where we are in the fog.

    • Thanks, Philip. Before this series is over I hope to debunk a few other myths and, for those interested in pursing NK, try to pass on all I’ve learned on the practice.

    • greensleeves

      Hi Peter:

      Please thank Dr. Phinney for the quick reply! So kind of him.

      “many young adult female subjects in metabolic ward studies who uniformly maintained nutritional ketosis”

      And that’s the rub, isn’t it? Most women on this diet are peri- or post-menopausal; some may be younger, but have PCOS. It’s interesting that altho’ most people who low-carb are middle-aged females, there is almost no research on them.

      What’s the bias here Peter? Do you know? Why no studies on PCOS or peri-menopausal women? Anyway, thanks for asking Dr. Phinney and thanks for the update.

  • Peter –

    I am still trying to grasp all the biology behind ketosis. So, I hope this question won’t seem ridiculous in light of what you have written. Most of what I see addressed with regards to ketosis is aimed primarily at men. I seem to slip more easily in and out of ketosis – despite a generally consistent extremely low carb and moderate protein intake, during certain times in my monthly cycle. I was hoping you might be able to address any differential impact of male vs. female sex hormones on ketosis. Moreover, I wonder if prolonged metabolic derangement (as a result of a very low-fat/high carb lifestyle accompanied by obesity for many many years), might also impact the ability to sustain ketosis differently for men and women. Thank you for your work in this area and the support you offer so many of us.

    • Risa, not a silly question at all. I must admit my ignorance, though. I have heard this before from women in ketosis, but I have not seen literature on it. I guess the question I’d have is why? Certainly catecholamines impact ketosis, but I’m less clear on the role of sex hormones. I’ll try to look into this.

    • greensleeves

      Hi Peter,

      “have not seen literature on it”

      Ask Dr. Phinney. He’s actually quite expert in this part of women’s health. It’s my understanding he’s researched this for a company, but has yet to publish about it. I was stunned by for example when he said that menopause is an inflammatory process and that your state of inflammation determines when it hits. This may also explain why some cultures, like the Japanese, don’t/didn’t used to experience menopause (very low inflammation diet).

      • Yes, I sent Steve and Jeff (Volek) an email immediately after receiving this comment. Look forward to hearing his thoughts. If anyone knows, it will be Steve.

        UPDATE: Here is what I heard back from Steve:

        Peter –

        To my knowledge, there is nothing in the peer-reviewed literature that answers this question.

        That said, I have had many young adult female subjects in metabolic ward studies who uniformly maintained nutritional ketosis as long as their diet was strictly controlled in an “extremely low carb and moderate protein” range (aka less than 30 grams of carb and no more than 100 grams of protein per day).

        In addition, we have done weekly ketone analyses on over 6000 clients in outpatient low carb clinics and did not stumble upon an a priori connection between low ketones and late luteal phase.

        What we did observe is that women with marginal ketones seemed to be more susceptible to pre-menstrual cravings (which of course nuked their ketones).

        Perhaps your blog reader might want to objectively test her ketones as you did. It might be instructive to see if her daily average blood ketones through her follicular phase is maintained above 1.0 mM but then falls below this threshold in the luteal phase despite maintaining the same diet.

    • Lila

      I’m having the same issues regarding ketosis during
      the luteal phase of my cycle, and so frustrated at the
      lack of information out their:( I function beautifully
      on low carb all month and like clock work, as soon as my
      hormones shift & serotonin drops….theres a breaking point
      in which my body becomes desperate for a carb fix…if I give in
      PMS symptoms increase exponentially (besides the immediate gratification of
      the serotonin fixes) If I don’t give in and stay on low carb I become very irritable
      and anxious (though overall pms is not that bad)…Peter I’d love your insight in the correlation between ketosis
      and serotonin production …does ketosis possible lower the need for serotonin? Or is the lack of insulin (to shuttle tryptophan ) a sign that females may need to temporarily shift out of ketosis when serotonin levels drop
      due to hormonal cycle?
      Best Regards!

    • Aggie

      Risa, Lila,
      I am having the exact same issues.

    • Janet

      Thank you for bringing this up. I too am having issues with going in and out of ketosis with a very consistent low carb/moderate protein and fat diet. My husband is eating the exact same things and has always had a high ketone count, whereas I have always remained on the border, fluctuating relatively with my cycle it seems. I would love an explanation why.

      And thank YOU Peter for all of your research and reiteration of material in a way that us less rigid people can understand. I am most certainly not a biology or chemistry expert (total opposite actually), and though I have a tough time with understanding some of the terminology, I was able to get the gist of the process far better than any other explanations. You’ve really made an impact on many lives, I’m sure. Again, Thanks! 🙂

  • Thank you most kindly for the two huge posts on ketosis. Despite both my degrees saying science on them, this reminds me why I dropped biochem at the first opportunity!! I’m nowhere near the limits of anything in terms of output nor endurance – rather I’m using a state of ketosis for managing a medium rate of weight loss (123 pounds in 18 months). In peak summer season it allows me to do 2+ hours of biking/swimming per day without extra bullets of sugar or carb loading or any of the other ‘proper’ geek routines.

    My question / suspicion is around the long term effects of ketotic states. Assuming that one has kept the plane of nutrition at or above adequate in macro/micro nutrients, AND, given the seamless entry point into the Krebs cycle, I see no issues why long term ketotic states should cause issues unto themselves. YES – if you’re limiting carbs or calories or whatever to the point where micro’s start to fall off the table — but that’s a problem with the ration balance as opposed to the energy cycle. Truth or Dare?

    Many thanks. Enjoy reading your posts. LOVE the summary points in the earlier posts!

    • Wow, Meghann, that is some profound weight loss and impressive physical activity.

  • Loving the detail you put into these!

    So, something I’m seeing some LCHF detractors start to bring up is how a high-fat diet will also make you fat through some mechanism I know too little about…acylation stimulation protein, or ASP. Do you have some information somewhere on your site regarding ASP? I don’t have enough understanding of ASP to give a retort and unfortunately, ASP is the acronym for “Active Server Pages” so searching on that is pretty useless. Plus I don’t yet know who’s analysis to trust.

    Anyway, what these people seem to be trying to say is that “well, sure LCHF has certain effects on the body, but really, they’re just switching one fat-building mechanism (insulin) for another (ASP) which also stimulates VLDL creation which is unhealthy”. Just wondering how to respond?

    • This issues has been addressed by the folks who studied it for a living, including Alan Sniderman at McGill (who I know personally, and who sits on NuSI’s scientific advisory board), Katherine Cianflone at Laval, and Keith Frayne at Oxford. The following link explains part of the story:

  • Toni

    Peter, your diet seems to be high in fat and cholesterol. I am 37 y old physician an have IIA type hypercholesterolemia with baseline LDL 300 and low HDL. I’m on lipitor 80 and zetia 10. My BMI is 28. I do not exercise much and eat what I want. I eat pita bread daily. Bad genes as both parents with CAD with dad’s first MI at age 39 (still alive at 66 now) Do you think your diet will be good idea for someone like me? I appreciate any help.

    • Doesn’t sound like what you’re eating now is optimal.

  • Christopher Tate


    An excellent if somewhat disconcerting trip down memory lane (it is amazing how much of Physiology 101/202 you forget) I can only echo the sentiments of others in hoping that this series of articles settles down much of the chatter of internet warriors and other pervayors of broscience. It really should be compulsory reading for anyone who either professionally or recreationally has an interest in nutrition and its role in health.

    I have been flirting with NK for awhile now and all the usal caveats of N=1 apply. But as a lifter I have my top end power has dropped off by a bit. As you would expect my capacity for work has improved but that vital bit of grunt at around 1RM has slipped.

    I dont have enough experience to know whether this is courtesy of a period of accommodation that will pass or whether other lifters who take the NK road have found something similar.

    Thanks again for the does of nutritional sanity…..

    PS: I am have no doubt you are aware of this in the recent JAMA – http://jama.jamanetwork.com/article.aspx?articleid=1555133

    • Interesting point. Have you tried supplementing with creatine to bridge the gap? 1RM is largely driven by this system, so I wonder if that would make a difference? I have seen the JAMA paper, but have not read it yet.

  • Birgit

    I was very interested in reading the comment about ketosis in women. When I first started I could stay in ketosis as long as I was under 50 grams of carbs/day. Now, 9 months later it seems to be closer to 25 grams. During the last 6 months I was only able to reduce my H A1c from 5.9 to 5.8 and my body fat stayed the same at 23%. I exercise at least one hour/day, often 2 hours. What’s my chance at this point to improve my insulin sensitivity and reduce body fat. My protein levels are rarely over 80 grams/day.

  • Taylor George

    Well, darn. I was hoping for smoking gun saying stating that NK would expend more energy. I’m competitive amateur cyclist at 14 percent (water dunk) body fat with 3 kids and a full time job, so I was hoping NK would help me to the holy grail of a sub 10%. After 4 weeks of LCHF and the latter 1.5 weeks at solid NK I have not dropped a single pound. I think I’ve gained 2 or three pound. Of course, so many variables: new winter activities such as weight lifting, XC sking during the same time. Bottom line for me though is that it does not seem to affect fat loss or overall weight loss. I probably need to go longer with NK, correct? I do have a better spread of energy throughout the days on NK, and I really enjoy the much reduced hunger at meal times too. I also dig not needing the gels on long endurance rides and skis.

    • Talyor, don’t give up on NK yet. At least wait until I finish this series before you make your decision. We’re barely half way there, and there’s lots more to discuss.

  • Sam

    I have been keto-adapted for the past 12 weeks and I will say that it was quite tricky to get there. It wasn’t a simple matter of just not eating carbs. I really had to up the fat and tone down the protein. Using a blood ketone monitor was essential (yes, it is expensive). I also find it is easy to temporarily drop out of ketosis, but not so hard to find your way back. When I am keto-adapted, I note a very distinct difference in how I feel. It is a sort of a mellow feeling and my energy level seems to be much more consistent and stable throughout the day. Then, at around 10, I crash and sleep very well. I don’t know if this is how it is with others, but, for me, this is a big benefit.

    • This sounds pretty typical, Sam, at least for the folks I know well.

  • Barbara

    Peter, your work is so fantastic and you and Phinny/Volek and others have transformed my approach to fitness (cyclist) and health. I can not follow all the science but get the idea of what you are talking about when you re-cap the essence of the post. I have been low carb for awhile and am now going keto to loose weight for spring road rides…

    I have more energy…my head and CNS are less anxious and my sympathetic nervous system is no longer on fire…

    Can you give some symptoms of keto adaptation ( do not have the meter to read this) so people can have some idea without the meter/science to verify?


    • Hmmm, hard to talk about symptoms of adaptation other than to note the absence of symptoms from not being there (e.g., lethargy). At very high levels of ketosis (typically over 4 or 5 mM), some people report euphoria and loss of appetite.

  • Donna

    Well done though I now have crossed eyes from the chemistry stuff. That’s okay because it was good. I just tossed aside a book written by a person on the that popular weight los show. I read the first few chapters and was amazed at how much nutrition information was incorrect. I tried to muddle through to see if there was anything worth while. Sad to say I didn’t find it. The diet premise of this book is to carb cycle. Eat high carb one day and low carb the next. I found myself grimacing as I read it. All I could think of was ‘of course, the diet works because the carb amount has been reduced’ not because there is magic in the cycle of it. It may help an individual lose the weight but the ‘addictive’ properties of carbs is still present and how many of us regain when we allow carbs to take over again. Just raised my hand. I agree with Volek and Phinney that a carb intolerant individual may never be able to go back to eating carbs freely.
    Oh and I would be interested in the male versus female hormonal impact on the ketotic state. I am also curious, though this is not the right spot for this, if the emerging female hormones at puberty may account for the rise in my obesity since I was of normal child size until puberty hit and then the weight piled on. If the female hormans excerbated a rising problem with insulin. May account why ketosis is harder to get into for some women. So many questions…..

    • Donna, I just responded to another question about the male/female issue, directly with a response from Steve Phinney. Look for that response in this post.

  • Martin

    Peter, it would be great to hear you and Robb Wolf disuss NK. In his latest post, Robb openly joins Chis Kressor and other neo-paleo bloggers in blaming low-carb / NK on thyroid disfuncton, low energy levels, fat re-gain, etc.

    • I’ll be sure to discuss with them next time I see them.

    • Jane


      Can you offer any more information about ketosis /very low carb and problems with conversion of T4 to T3?


      • Not at the moment. More work needed. But T4 and T3 aren’t the issue. Focus should be TSH.

    • Jane

      Hi again Peter,

      Thanks again for your patience and dedication.

      Would the focus on TSH be correct even for those on full T4 replacement AND in ketosis? Many folks have no functioning thyroid at all, and struggle to maintain what would be a “normal” homeostasis, even relying on only TSH.

      I guess more research is needed, and I sure hope that there will be NuSI-backed or other research that includes full thyroid panels to measure the more detailed effects of ketosis on the T4 to T3 to rT3 etc. balance, and that some include subject as on thyroid replacement.
      Most research designs screen out subjects already on medications, and, of course lab norms and clinical research usually include mostly subjects on conventional diets, as far as we know.
      But then I have not done a full literature search.

      • No. If thyroid replacement is taking place, different set of metrics (clinical and lab). I am not expert in this, and a good endocrinologist is necessary to manage this (with or without ketosis).

  • Dave


    “I mean this most seriously. If you toss open Louis Diat’s classic ‘French Cooking for Americans…'”

    Thanks for this recommendation. I found a copy on Amazon Marketplace for ~$6. I’ve never been much of a cook but it seems like this style wouldn’t be too difficult to learn. Maybe I’ll be able to impress my wife with something tasty AND LCFH!

    • greensleeves


      Go for it! Plug the recipes into an online system, and if by any chance they come out low on fat, add cream, more butter (Julia almost always adds more butter than Louis does), or coat with bechamel/bernaise/hollandaise/cream fraiche/sour cream/cream cheese.

      We have to ask ourselves how French people used to stay so slim! It’s that they used to eat 70-75% fat at every meal and only about 70-100g carbs, while walking everywhere.

      Of course it’s not hard to do – illiterature peasants made these delicious dishes for ages, French women in middle-class families who could afford to added more cream and a slice of truffle – I mean it just takes practice. The kohlrabi/turnip/cauliflower subs are easy too and almost no one notices ever.

      Everyone loves this food. Good luck! 😀

    • Al

      Greensleaves: “and plug any of the classic recipes into an online system” Can you or anyone who might know point me to some links for such systems? I am keen to test this hypothesis with various French and other recipes from the early 20th century.
      Thanks in advance.
      Peter: thank you and please keep up the great work, very inspiring.

  • Eric

    Was the font change right after the ” This study by Sears et al. is a representative study and underscores the biggest problems with addressing this question:” piece of text intentional? The rest of the article has a much smaller font which makes it slightly harder to read.

    • I was having some technical issues with this post. This was the best I could do.

  • Barbara

    Peter, once again you out did yourself. I have to say I am not able to take in all the science of this blog post but do get the idea based on how you sum things up. You have transformed my relationship with food and cycling via my going LCHF and using ucan products. The fact that you are an endurance athlete and have transformed your health and improved your output re your sports has influenced me a great deal.


    • Thank you for sharing, Barbara. Great to hear.

  • Great series, I’ve enjoyed reading all your articles, but this in-depth look at ketosis is amazing! I’m looking forward to the last two posts!

  • Dr. Attia,
    If you have time, would you mind explaining the difference between being “keto-adapted” and “fat-adapted?” I’m afraid I just don’t understand what people like Mark Sisson mean when they say you can be fat adapted without necessarily being keto-adapted. It seems from their recommendations that this state happens between 50-150g of carbs and seemingly no limit on protein. Wouldn’t this just be a glucose-based way to fuel the body? Is this truly a state different than both glucose-adapted and ketone-adapted? To me, this seems like it would be in the “zone of misery” where both glucose and ketones were low. Does this question even make sense?

    • I’m not exactly sure. I certainly know what keto-adapted means, but I suspect fat adapted is a step in that direction, without producing enough ketones to meet the brain’s requirements. Perhaps it implies some threshold of lower RQ and higher ability to oxidize fat across a broader range of exertion.

  • Rob


    Have you seen any credible studies that link ketosis with kidney stones?

    • No, but it’s certainly possible due to the changes in how the kidney process minerals. For this reason I supplement with calcium carbonate, which I’ll elaborate more on in subsequent posts in this series.

  • Just finished reading Volek and Phinney’s book on low carbohydrate performance. If I recall correctly they said blood levels of leucine were higher in competitive cyclists on a ketogenic diet (10g carb) whereas cyclists on a typical high carb diet had greater leucine oxidation, and therefore less anabolism compared to the ketogenic cyclists. I believe they reasoned that the ketones spared the oxidation of leucine by the muscle, which instead used ketones as fuel. Less leucine oxidation in the muscle, and more leucine in the blood to stimulate protein synthesis even with low physiologic levels of insulin. Also interesting to see that protein synthesis did NOT increase any more with added carbohydrate post workout, like most people think is necessary. Good stuff as always Peter, good timing too!

  • Richard, Jeff Volek and Steve Phinney described it that exact way. Too much glucose for the body to get into the keto adapted state, but not enough to supply the brain and muscles energy that ketones would be providing if cabrohydrate levels were under 50 grams. Like a zone of misery as you said. They discuss in depth what keto-adapted is.

  • Dont Tread on Me

    Hello Peter. Your article is very much over my head but I I have a question on the subject. I have mitochondrial myopathy classified w/ no known genetic mutations. My neurologist said there is no specific diet I should be following but I wonder how a ketogenic diet would be for someone like me? I’ve been eating a paleo diet for 4 months and try to get carbs through daily sweet potatoes and plenty of veggies.

    • I don’t know. Is current diet an improvement for you?

  • Aaron

    Is it possible for one to accidentally undergo ketosis? I’m a vegetarian but I tend to eat high protein, high fat foods naturally. I haven’t been checking the carbohydrate content of my meals so I’m not sure if it’s actually a low carb diet, but the fat and proteins definitely make up a large portion of my calories. The reason I was lead to believe I might be in ketosis is that I’m a competitive distance runner and almost every day I smell acetone coming off of my body for about 10 minutes after exercise. This seems to be a symptom of ketosis but I’m not sure if there’s anything else it could be. Also, to my knowledge I do not have diabetes.

    • It is possible, I suppose, and certainly vegetarians can be in NK. It typically requires some work, though, and a deliberate attention to carb (vs. protein content, which is usually the omnivore’s problem). That said, there are many days I am in NK where I do not consume any meat, so it’s absolutely feasible.

  • AT

    I am not sure I would call the LCHF without being keto-adapted state a zone of misery. If anything you still have a much higher chance of avoiding metabolic/hormonal syndrome and also be a lot more energy efficient in your aerobic/tempo training. Personally, with everyday life in the way and the occasional beer I find it hard to stay in ketosis but have enjoyed massive benefits as a triathlete and in general wellbeing by cutting out all grains, sugar and starchy carbs.
    My question for you Peter is, on a theoretical level (wouldn’t expect a yes or no answer for this), if you follow a LCHF lifestyle (including 15-20hrs of endurance sports training a wk) with chronically low insulin levels, then on race day ONLY you give your simple carb intake a boost, wouldn’t that give you a big advantage vs high-carb athletes considering your body would be heaps more efficient in using those carbs as energy? The thinking being that you would be a LOT less insulin resistant than the rest of the field?
    Saving it for race day only would also make it relatively safe to do so as well. Just a thought..

  • Dont Tread on Me

    The paleo diet has eliminated my iron anemia which I had previously even while taking daily iron supplements. Pre-paleo my 5000 IU vitD supplement had my blood levels at 41ng/ml and now its 71ng/ml. Pre-paleo triglycerides 43, HDL 42 and Post-paleo triglycerides 19, HDL 65. I haven’t been able to find much information on triglycerides at 19 could be getting close to being too low.

    I haven’t noticed any change in the muscle myopathy on paleo but I just hope in the long run I am eating the best way for the good mitochondria I have left.

  • Dear Peter,

    Thanks for the post, its amazing the efect of your ketones in your writing productivity! 🙂

    There is something in Barry Sears article which woried me; that the ketogenic diet increased inflamation!
    Is there any real evidence about it?
    I have a high LDL-c (about 200) but also high HDL and low TG, and I just do not care anymore, as I think that a very low carb, low seed oil, high olive oil and high fish oils should prevent inflamation.

    • I’ll cover this in Part X of the cholesterol series when I can get to it.

  • Matthew

    Have any studies looked at the effect of ketosis on mental performance?
    I have a specific professional interest in this. I fly for a regional airline,
    which means that I am often on duty for 10-12 hours, sometimes early, sometimes
    late, working 6 or more short flights. The job is not athletically demanding,
    but it does require a high level of performance in perception and judgment, at
    varying times of the day and despite an inevitable lack of sleep and regular,
    good-quality food, not to mention noise, repeated pressurize-depressurize
    cycles, turbulence, etc.

    After four months of eating <50g of carbs daily (down from ~300), I'm fairly
    certain that eating low-carb does help me do a better job. My _feeling_ is
    that I'm more alert and performing at a higher level. I _know_ that I no
    longer have to eat every two hours to avoid drowsiness and headaches that
    hurt so much I want to vomit.

    This is great as far as it goes, but I know N=1 doesn't count for much.
    That's why I wonder if any research has been done that might shed some light
    on the effects of ketosis on non-athletic performance.

    Thanks for all your work Peter.

    • Yes, quite a bit. Should get to this in part III…or IV…

  • Dont Tread on Me

    I had posted earlier that my triglycerides on a paleo diet have dropped to 19. I was wondering if that might be getting too low. To give you more information, Pre-paleo triglycerides 43, HDL 42 and Post-paleo triglycerides 19, HDL 65.

  • Al

    Peter: One thing that I’m still not clear on is whether one can be in nutritional ketosis and still have high blood sugar? I understand that high insulin is a barrier to NK but what if one has low insulin and high sugar? Inspired in part by your work and my own early successes in low-card dieting, I’ve started monitoring my blood sugar using the Precision Xtra strips. What I’ve noticed is that my one and two hour post-prandial sugar is invariably good (90 or below) but my fasting level is frequently over 120. It’s as if my body produces glucose while I sleep and then can’t get rid of it until I eat or exercise? This is particularly troublesome to me as I’ve gotten into an intermittent fasting routine where I won’t eat after 10pm, have coffee with a spoon of cream before work, go to the gym around noon and then have my first meal around 1pm. That’s a long time (potentially) to be in a high-sugar state each day (from some time overnight to just before noon). Any ideas as to what might be going on? Admittedly the fasting sugar is higher when I have sugars as part of my evening meal (around 7) or have ice cream after supper but it happens even when I’ve had a prettly low carb, no-grains or sugars day – I’ve almost never registerd a waking fasting glucose below 100 despite having last eaten a low-carb meal 10 hours ago. Then, during the same day I regularly hit 80 post-prandially. Should I be concerned? Should I abandon IF?

    • I definitely noticed higher “fasting” sugars early the fasting day while in IF than now that I’m back in “regular” ketosis. Not sure if the difference is clinically significant, but I do note my fasting glucose is lower when not doing IF.

    • Martin

      Al, I have noticed a similar regularity, still not sure what causes what though. When I introduced regular blood and ketone measurements last summer and adjusted my foods to get into the NK state (as discussed in Volek & Phinney) my fasting blood glucose stabilized at ~80-85 with the blood ketone levels above 1mmol on most days.

      Some two months ago I started IF (I had done this before but never monitored my glucose so closely) and in general I feel good about it, but some time afterwards my fasting blood glucose rose to 100-110 and my blood ketone levels went down slighly. There could be different explanations: I started working out a bit more, it’s winter time, more work and more stress, etc. But it could also be the IF.

      The problem is that I have no idea what the mechanism behind would be: last night I had my low-carb, high fat, meal at around 6pm. At around 8pm my blood glucose was at 82 – perfect. I had a good night sleep and this morning my blood glucose is at 99. The question is: how would skipping breakfast on day 1 affect fasting blood glucose on day 2 ? I would rather expect and certainly wish my ketone levels to go up (this morning it was 0.4 – a bit lowish). On the other hand I feel good during the day and have no problem with fueling both endurance activities and short, intensive work-outs.

    • Martin


      >> I definitely noticed higher “fasting” sugars early the fasting day while in
      >> IF than now that I’m back in “regular” ketosis.

      did you have any good reasons, worth mentioning here, to give up IF?

      As mentioned in the other comment here, I feel good doing so but I am not sure if it is not interfering with NK.

    • Tracy

      This is my experience too. High fasting levels which continue to rise until I eat. Very low blood ketones despite a ketogenic diet with 60g protein. I’ve been harassing heaps of people about the impact of high blood sugar/insulin on ketosis. The general consensus is ketosis is difficult to achieve once bg levels are over 80. Not good for me as my fasting/baseline levels are 100/110. My problem is that I’m convinced I can’t lose weight until I get into NK and I can’t get into NK until I lose weight (ie get my bg levels down to normal) . Peter, can you point me to any research about ketosis and diabetes, or even ketosis and high insulin levels ? Is ketosis resistant diabetes the same as diabetes type 2 ? I guess I’m wondering how diabetics (not type 1) ever get into ketosis ?

      • Look at the work of Hussein Dashti. Lots of experience using KD in T2D.

    • Joakim

      I am also doing low carb IF (less than 50g carb/day). Only eating one meal a day in the evening around 6pm. I have noticed around 100 fasting glucose but during the day and after the evening meal it normally stays below 90.

      Looking forward to hear more about this

  • Spar

    Hi Peter,

    Did you have any regularity problems? Did you have to supplement extra fiber? Also did you subtract fiber from your overall carb count per day?

    I have rad that you have been below 50g and then above 50g of carbs. I understand the benefit of being below 50g, since you will produce Ketones. But what is the point of being between 50-100g? Don’t you stop/limit your ketone production and might not be getting enough glucose? I guess what I am asking, would it not be more dangerous to be in the borderline of Ketosis instead of in Ketosis?

    • No problem at all, which I attribute to the following: I still eat more salad than most folks can dream of; the bouillon; probiotic. I no longer take MCT oil, which I thought played a role, but evidently (for me, at least), didn’t seem to matter.

    • Tracy

      Thanks Peter. I read Dashti’s studies. All point to good results for T2 diabetics on a ketogenic diet. Weirdly, though I couldn’t see anywhere where it said they measured ketones before and after implementing the diet. So how do they know the diet was ketogenic and not just very low carb ? I probably missed it. But anyway perhaps it’s not important, the main thing is that the participants lost weight and improved a whole swag of things !

  • Ilan Benador

    Great post, thank you.
    Do you think thyroid hormones play a role in diet-induced TEE changes?

    • Possibly. There are several candidate pathways, none of which are mutually exclusive.

  • Debbie

    I got lazy and stopped the bouillon. And I’ve been eating some “bad” foods – a half cup or so of rice, a little sweet potato occasionally. I’ve actually dropped a few pounds (I’m 57 and cannot be slim – I’m 5′ 1″ and probably weigh about 133; my top weight was about 215 25 years ago) and feel better than I have in a long time – more energy. I have no idea why! Anyway, I keep telling myself to drink the bouillon, but then don’t… on the other hand, I eat processed turkey and canned salmon almost daily, so maybe I get enough salt there. I know – processed = bad. I hate to cook. 🙂

    • Zac K.

      Hey Peter, I have been doing ketosis diet on and off for about 2 years. I am currently in medical school and it is funny to debate with people why I do and the benefits. I have done labs twice one control and one about 6 months ago. They were very similar to yours. I used to play college football and was, at my highest was 315 lbs. Granted I was very strong and athletic. This diet was the only way for me to get down to my current weight of about 225 lbs. I do still like to lift weights, very heavy at some times. I do mild cardio most days. My question to you is pre-workout/intraworkout supplements and their effects on ketosis. I usually go to the gym in a fasted state, but cant seem to find any information online as to whether pre-workout drinks with the normal creatine and BCAAs will hinder the benifits of ketosis and fasted state exercise.

      • Zac, I use BCAA (about 5 or 6 gm) in-workout (otherwise fasted), then about 5-6 gm glutamine + 25 gm whey post-workout. This does not appear to hinder my ketosis, per se. The actual HIIT is probably doing most of the transient hindering due to marked HGO.

  • Spar

    Hi Peter,

    Are you currently below 50g of carbs or did you permanently increase it above 50g? Why do you not use MCT oil anymore? Is there a reason why you keep high monounsaturated fats?

    • Yes, well below. Probably 20 gm/day. Just stopped using MCT and it made no difference. Maybe carbs and protein are low enough now (ketosis, round 2) that I don’t need the kick-start.

  • Pierre

    Peter I noticed that you stopped taking MCT oil…can you share the reason why?

  • Zak Hendsch

    I’m not sure I’m understanding this correctly, so my question may be hopelessly naive. The Hall Paradox (I think) says that burning B-OHB is more efficient than glucose but that making B-OHB is less efficient than making glucose. So my question is: how long can you exercise before you burn through the already circulating (or stored?) B-OHB and have to start making more. How long does an exercise session have to be before the extra energy cost of making B-OHB makes it less efficient than glucose (overcoming the extra efficiency of burning the already circulating B-OHB)?

    • Almost right. B-OHB, when oxidized, gives more ATP per unit O2 than glucose. But we get glucose for “free” (we eat it). We need to make B-OHB out of our fat, that costs us energy. To answer the question, pretty soon. Our plasma amount of glucose or B-OHB gets used up very quickly when we’re exercising, so we quickly turn to the liver to give us more of both.

  • Hi Peter,

    Thanks for all the articles. To be completely honest, most of the technical information goes over my head but I get the general idea. I have been on a ‘cold turkey’ <50 carbs a day for about a week now. It has been difficult as I'm still swimming 2.5km about 7-8 times a week so doing this with headaches and some nausea has been difficult. I am starting to have a bit more energy so hopefully I’m getting towards the end of the worst… I am battling to find resources on the web that give example diets and I’m struggling to lower my protein intake. I’m also struggling with how to increase my fat intake. A lot of searches for low carbs diets seem to point to information that contradicts a lot I hear here and so I can’t take the rest of that site seriously. I have my own criteria for who i believe on facts – If the person is prepared to admit they are wrong if presented with real evidence to the contrary then I am more likely to believe what they say. People like you, Gary Taubes & Prof Noakes fall into this category. In the coming months, I am going to start increasing my swim distances so if anyone can help out with info on increasing my fat intake as well as feeding around the swim, I would appreciate it. (I would love to get my hands on some UCAN Superstarch, but unfortunately this is not available in the UK)

    • David, Check with the UCAN company. I do believe they can ship to the UK. It may be worth trying a more gradual approach to your dietary intervention, versus a dramatic shift to ketosis. Take a look back at my path to ketosis in 2009-2011. Very slow and gradual…

    • James

      Hi there,

      My path to ketosis was quite fast (2-3 weeks) after eliminating most high carbs food (grains / sugar / starches). My fat intake increased quite a lot (fat cheeses, oil, butter / ghee, lard, etc).

      BUT, I knew I would feel a bit funny during the transition so I did NOTHING at all in terms of physical activity. I waited for about 1 month before being active (cycling, hiking for hours, etc). Note that I do not try to be the fittest, strongest, most endurance hardened person in the world, I just want to have fun and feeling all the energy I feel today allows me that. If I were you, I would stop the swim for 2-3 weeks. I know you will probably think that you are slacking off, or whatever, but changing your metabolism from sugar burning to fat burning is too big a change and your body will surely be “fatigued” during the transition.

  • KC


    1 more question about MCT. I see you stopped taking it. Have you stopped ingesting Coconut Oil as well?


  • Hemming

    Hi Peter,

    I’m sorry to hear about your friend Woody.

    It will be really interesting to see the data from the study by Veech & Clarke. From personal experience I feel most ‘energised’ when I wake up in the morning after not having eaten for >11h. I would expect my ketone levels to be the highest (I don’t have a device for measuring them) at this time of day.
    Have you ever tested this yourself by performing the same type of exercise with (statistically significantly) different ‘starting’ ketone levels?

    Keep up the good work!

  • Peter,

    This information came at a pretty convenient time.

    I recently had blood work done for a physical and my liver enzymes were elevated (AST=41;ALT=86) so that caused my physician to be concerned.

    I recalled this series as well as the physician being surprised at how my ketone level was and thought to myself that my liver enzymes could be elevated because my ketone production is high (I’m also sure the multiple shots of tequila as well as some wine that I had on Saturday night did not help either!). I tried looking through your diagrams for ALT/ALS and couldn’t find anything. A wiki search however revealed that ALT is used to produce alpha-ketoglutarate.

    This leads me to believe that my initial guess was correct in that liver enzymes were elevated due to:
    1) fat adapted –> high ketone production –> high alpha-ketoglutarate –> high ALT/ALS
    2) high alcohol intake 36 hours prior to the test (note: I do not regularly drink heavily)

    Is my understanding correct?

    Thanks again for all of the information you provide at this site.

    • Now that I think about it a little more I’m going to eliminate (1) as a possible cause and leave it just as (2).

      From studying your diagram more it appears that AST/ALT are only used in Glucose-CoA pathway and not the the Fat-CoA chain. This leads me to conclude that (1) is not possible. I think it is much more likely that the high AST/ALT levels were from the alcohol consumption I had less than 36 hours prior to the test.

      I also forgot to consider that my ketone levels were from a urine sample I took today and not at the time the blood was drawn (Monday). Therefore case (1) falls apart completely.

      Please let me know if this is correct.

      Thanks again.

    • ….forgot one other crucial thing.

      <36hours before the test I consumed almost an entire Chocolate Wall of Cake (376carbs) from PF Chang's. Certainly not my proudest moment.

      I think I know why my liver enzymes were elevated….

    • Interesting hypothesis. I, too, had mild elevation of AST and ALT for about 6 months. All better now, so hard to say. Could have been a viral infection, could have something else. But, as you point out, could have part of the adaptation. Just had a liver MRI 2 days that showed zero fat in my liver.

  • Marianne

    Your site, although technical is very accessible to non scientists like myself, many thanks for all the information. One question not specifically addressed is why some indivuals become insulin resistant, while others don’t? Having been pretty skinny all my life I rapidly gained weight after surgery to remove my ovaries, so in my case it would appear to be hormone related. Staying low carb has fixed this and I now maintain easily at 65 kg 169.5 cm tall. But I don’t understand why one of my sons (aged 42) is obese, now thankfully starting a low carb diet, whilst the other remains very slim (aged 30) whilst apparently consuming refined carbohydrates and high sugar sodas? In spite of eating all the wrong things, there do seem to be individuals who remain slim throughout their lives, are you able to shed any light on why this might be the case?

    • Hard to make a case that hormones aren’t playing a role, huh?

    • alice russell

      i agree some people appear to be able to eat anything and remain thin.
      not specifically healthy but thin.
      i have read in various artilcles that around 25 percent of people have the ability to break down or use the carbs in a more efficicent way then the 75 percent majority.
      although health and weight are connected i do not see all thin people as healthy people. fit and thin are not the same.

      • Important distinction, of course. Just because one is thin doesn’t mean healthy. 7-10% of adults who are normal or underweight have MetSyn. “Only” 65% of obese adults have MetSyn. Best to focus on metabolic health, rather than weight. My TED talk in April will focus on this.

  • Nick Jones

    Hi Peter
    Just came across your site, although I have seen your interview on Youtube. I have been low carb for the past 4-5 months and am now at a below 50g Carb level per day. I am a 50 year old competitive runner and must say that my energy levels are so high now. I am absolutely flying in training and fully expect, not only to set Age PR’s, but absolute PR’s this year from 5k upwards. I am convinced this lifestyle is the way to go.
    At last nights club 8 mile tempo run I nailed my previous best time by 40 secs in a much easier effort level than the previous time. I even ran my son close and he is a 33 min 10k guy. I do feel sort of buzzy, in a hightened state for want of a better word and not sure if this a symptom of ketosis. Even my 20 mile long runs I can do without any fuelling and do not see any detriment at all.

    Great site and keep up the good work. This message needs to get out.

    Kind Regards

    Nick Jones
    United Kingdom

  • Ashley


    Thank you so much for your work and blogs. I have my doctorate in sports nutrition, and never during my education was I even introduced to this topic of nutritional ketosis and performance implications. You and others like Taubes, Sisson and Volek have really flipped the world that I have known upside down- I like it. I’m currently completing my dietetic internship to become a registered dietitian and once again low-carb, high-fat eating is almost viewed as blasphemy by most. I, however look forward to speaking out and supporting these concepts within the professional nutrition community.

    I do have a question for you regarding sport performance. I provide a lot of nutrition education to teen and professional ballet dancers. These athletes require power for short aerobic stints (no more than 5-minutes of consistent activity, but potentially 6 or more hours of this on and off throughout the day) as well as anaerobic power for large jumps/partnering, etc (similar to gymnasts). They need endurance capabilities which makes me feel like a lower carbohydrate diet would benefit them. A lot of them also constantly struggle with maintaining the low body weights often required (dancers actually don’t burn many calories, and are taught to eat moderate/high carb to fuel their activity. Very low calorie diets are usually what they succumb to and as a result their metabolic rates are significantly depressed and the female athlete triad comes into play). Like I mentioned before, however dancers do need to tap into their max efforts. I noticed in one of your blogs that ketosis negatively affected your top-end power. I bet dancers challenge their VO2max multiple times a day. I’ve also read in your blog, however, that you have no issues with intense resistance training (I can’t see tire flipping being much easier than what they are doing ?) So, I’m wondering: do you think a low-carb diet would benefit this type of athlete in a non-steady state/high-intensity type of activity or would it detract from their top-end performance capabilities? If a dancer isn’t quite ready to get into nutritional ketosis, but I urge them to reduce their carb intake (say to 100-150 grams as Mark Sisson suggests) would this be helpful or put them into a mid-zone that only hinders them? Prior to all of my recent readings, I recommended (via conventional wisdom) complex carbs for breakfast, a pre-activity higher carb/low fat/moderate protein snack and then of course, the post-activity recovery snack of carb/protein (3:1). Now, I wonder if I am doing them a disservice. With this recommendation they can’t up their caloric intake and continue their battle with weight and other health concerns. Thanks so much for your insights.

    • Interesting question. I just saw this paper last month. Don’t recall who sent it to me, but it seems to try to address your question:


    • Hemming

      Hi Peter,

      In that they consume 2.8g protein/kg which seems rather high (even though they say it’s to preserve lean muscle mass). I would think that 2g protein/kg was closer to the upper limit.
      Have you seen any studies on how much protein one can eat without going out of ketosis? How much is gluconeogenesis related to absolute body weight vs. an absolute of protein? I’m thinking that a fixed amount of protein will have a more negative effect for a lighter person compared to a heavier.
      If I may ask, how many grams of protein per kg/lbs of body weight do you aim for?



      • It’s probably a function of timing of protein ingestion and anabolic need. I aim for about 120 gm/day, but with very special attention to when I consume it.

  • J

    I am patiently waiting for the next in the ketosis series- specifically, a nuanced explanation of what to eat to get (and stay) there! I have an extremely hard time keeping protein levels down. I know that I probably need to increase the fat quite a bit, but I just can’t seem to get there. I always end up eating more and more protein to get that “full” feeling, but have realized that I’m probably eating almost 200g of protein a day- and I’m a 5’4″ woman.

    I guess I’m hesitant to up the fat so much because I’m still mentally tracking calories in my head (I know, I know, but old habits die hard). I’m concerned that I will just keep upping the calories with fat but not really feel satisfied.

    I’ve tried upping fats “independently” of meat before (lots of EVOO on salad, MCT oil, etc.) with no success in terms of satiety. My new approach is to eat only fatty cuts of meat and moderate added fats.

    Have you heard of this issue before? I’ve been LC for a year or so, but haven’t succeeded with ketosis at all.


  • J

    One more thing:

    For a 5’4″ woman weighing around 120 pounds, what would ideal ratios (on average) look like? Reading through comments, I see people eating anywhere from 50-150 grams of protein daily- I seem to remember you saying less than 150 would achieve ketosis (generally) as long as carbs are under 50g.

    Sorry to be so nitpicky- I’m just anxious to get it all “dialed” in….

    • Will discuss later in this series. You’ll want to hear the full story before you decide to dial in.

    • Annlee

      J — you may want to wade through these threads



      There are several discussions of what numbers to use. Personally, at 5’1″ (155cm) my goal weight (age 61 – postmenopausal by several years) is 110-120 (50-54kg). I use 50-55g protein, 25-28g carb, and the rest is fat (from a combination of diet and current stores). This works for me. Some folks split the protein into multiple meals, some do one meaty meal per day. There’s a lot of finding what works for you in these threads.

  • kang


    Can you talk a little bit more about the LC/NK impact on the urine data ? Jimmy Moore just posted his urine test results, 3+ protein, rbc presented in the urine, plus calcium oxalate crystal, cloudy and foamy urine, high specific gravity, all pointing to some sort of Kidney damages. Is it caused by lower carb intake or higher protein intake ? You know Jimmy is doing LC/NK for years.


    • I’m not familiar with Jimmy’s urine data and am not in a position to comment on it.

  • T Tarrier


    I was curious to see what you thought about Berberine, specifically what is mentioned on this site:

  • Pingback: Life is life()

  • Karsten

    great thoughts on this blog, thanks!

    I’m on low carb for quite some time now (approx 2 years, even not in strict ketosis, some cheat days) and love it! My wife a bit less, she complains I smell of acetone, obviously one of the ketone bodies.
    Is that an indicator I’m in NK?
    Is acetone smell typical for NK?
    Is there a way to avoid that smell and yet stay away from the carbs?

  • You mention you pay close attention to the timing of the protein consumption, but you don’t say what that timing should be? When should I (or shouldn’t I) have protein, ideally?

  • Richard S.


    I’ve lost 30 pounds, will soon have a BMI of 25, and no longer need my BP meds – all from following your example. I can’t thank you enough.

    From your posts and videos, I understand that insulin is an anabolic (building) hormone – that it helps the body use proteins, fats, and carbs for energy and store them as muscle and fat. I also get that while carbs cause a significant insulin response, protein causes some and fat causes none.

    I get that eating these foods together can change their glycemic effect and our insulin response. (For example, that eating bread with olive oil or cheese may be better than eating bread alone.) But if someone eats plenty of carbs and fat together, they will get a significant insulin response. I’ve read that the body then does a great job of storing both dietary fat and carbs as body fat.

    My question is this: I wonder if there might be additional benefit by eating one’s protein and fat at different times. The idea would be to eat lean meat and other protein alone, with no carbs and little fat, so the insulin response just helps build muscle. Then, when the insulin level has dropped, one would eat fat and other foods while still avoiding carbs (e.g., cheese, bacon, veggies with butter, salad with a high fat dressing, etc.).

    In short, do you think it might help to eat fat mostly when one knows the insulin response will be low (from not eating protein and carbs)? Do you know whether anyone has tested this, or tried it on themselves?

    Don’t get me wrong. I love eating meat with fat and it’s easier to eat normal meals. You are at your goal, and I’m getting there, so we might not need to bother with it. But I know others who say that the low-carb approach just doesn’t work for them. I tell them to make sure they really cut the carbs (e.g., to fewer than 20 gms/day). But I wonder if this might help them see results faster – not by changing what they ate as much as changing when they ate it.

    Thanks again!

    • Very important question, Richard, and one I think about a lot. Your assumption certainly makes sense, but I’m not sure how much experimental data out there confirms it.

    • Hemming

      Hi Richard,

      I’ve been thinking exactly the same. What I do currently is to have the bulk of my protein and carbs at breakfast and dinner because I bike to and from work (I’m thinking that the exercise will help lower the insulin response). At lunch I’ll limit protein and carbs, usually having mainly a salad, a little meat and olive oil to negate the insulin response.
      I apply the same thinking around the ‘real’ exercise sessions. I’ll have more carbs after those as I think it’s better to have the hgher insulin response at that point. I still have fat with those meals though.
      I think I have to try your suggestion of keeping the fat low at a post-workout meal to see if I hopefully can gain weight with that approach.

      Best regards,


    • Marijke

      I think you need to eat fat with your meat to be able to digest the meat.

  • Martin

    It does make lots of sense and I have been thinking about exactly this: eating my fat and proteins at different times.

    However, from what I understand (after reading Phinney and Volek’s books), free fatty acids are available in the blood stream at all times, and for the cells that will absorbe them, it does not matter whether they come from the meal you have just eaten or have been released from the fat cells. If the insulin levels go up, the fat cells will start storing them. So in the end it might not matter if you eat protein and fat at the same time.

    On the other hand, it’s probably a good idea to eat more protein and less fat after the workout and then limit the protein and eat more fat at other not-post-workout meals. This is the approach I will want to test: fat only for breakfast (basically coffee and/or tea with coconut oil and heavy cream), a workout around noon followed by a higher-protein, lower-fat lunch, and for dinner, some meat (not too much) with green vegatebles and enough fat not too be hungry.

    • Richard S.

      Thanks for the responses. Interesting observations. I’m still debating whether and how to experiment with this. I’ve gotten so used to eating fat and protein together, and have come to really enjoy it. (The sauteed mushrooms made my hamburger taste so much better last night!)

      My diet path has been somewhat similar to Peter’s — from low-fat, to lower-carbs and whole grains, to high-fat and no carbs. My success has been similar too. (Except I don’t work out at his level. But who does?) I might go back to the high-protein, low-fat, low-carb approach for some meals (e.g., for supper, when I get most of my protein), and focus on eating higher-fat, lower-protein meals and snacks at other times. If I succeed in giving it a good try, I’ll let you know how it goes.

  • Thank you for this blog – it is exactly what I have been seeking. What are your thoughts on LCHF for those of us who are being treated for hypothyroidism? It seems that both calorie restriction and VLC reduce T3. The last thing I want to do to his reduce my already slow metabolism even further. I am looking to lose about 15 lbs of fat. In the past, LCHF has worked for me, but it seems since being treated for hypothyroidism, it doesn’t work as well. I am not looking for medical advice, just wondering what your thoughts are on LCHF and T3. Thanks!

    • Very misunderstood topic, and probably stems from an unclear understanding of clinically significant hypothyroidism (vs. lab value abnormality — typically normal TSH, but low T3 — this is probably not hypothyroidism).

    • Michele

      Hi Peter,
      I know you are already busy enough but is there any reliable information concerning insulin resistance and significant clinical hypothyroidism (i.e. due to a thyroidectomy)?

      I ask because if you say the topic is not clearly understood, I’m hoping there’s some good info out there which you may have gathered for your upcoming post “Relationship between hypothydroidism and insulin resistance”.

      I am aware of Chris Kresser’s info on the subject but anything else would be appreciated.

      I’m grateful every day or the knowledge you share!

      • Chris has probably thought most about this. Also, check with Ron Rosedale.

  • Richard S.

    Peter –

    Wait! I think I just found solid evidence that contradicts my theory about eating protein and fat separately – one that provides further support for eating meals with plenty of fat.

    This 2009 study (Am J Clin Nutr 2009;90:986-92) analyzed the insulin responses from eating different meals. One of the strongest correlations they found was a negative one between the fat content of the meal and the insulin response (r = -0.60, P = 0.03). This negative correlation was even stronger than the positive correlations found for either the carbohydrate content of the meal or its glycemic load.

    I’ve often wondered why eating fat seems to help so much. (Even on a no-carb diet, one might think that fewer calories would help.) Here’s another possible reason why. When one eats other foods and fats together, the dietary fat helps to reduce the insulin response from those other foods!

    So, I think I’ll continue to eat plenty of fat with my protein, as I have been.


    • Martin

      Richard, it is truce that fat blunts the insulin response. But if you consume protein after the workouts, elevated insulin for a short time is exactly what you want. Also, if you eat real food, you can’t really separate protein from fat, can you? I did some climbing at noon today (1 hour of intense bouldering) and the had my ‘higher’ protein lunch: 3 eggs and a can of sardines on olive oil, ca. 45g of protein. I did not add any extra fat (e.g. butter, coconut oil, a salad with plenty of olive oil) and still I did get plenty of fat from eggs and sardines.

  • Miruna

    Peter, I read your posts with great interest. I have recently changed my eating habits, decreasing carbs, and my health has improved dramatically. It is for me a new way of life, and a much better one! I like your writing approach because is scientific (and I have a science background myself) so it really makes sense to me. Many, many thanks for sharing your knowledge to the world, you made a real difference to my life.

    There is however a question that I am trying to find an answer to, and I thought you are the best person whom I can ask:

    What is your opinion about pure vs virgin coconut oil?

    It makes sense to me that the organic virgin coconut oil is indeed the best one to eat, if having it raw. However, which is best for cooking? I am currently cooking with pure coconut oil because it’s much cheaper, it imposes no flavour on the food, and I believe that it has a higher smoking point than the virgin one – but is this really true? (I tried to find an answer on the web but with no avail.) Or, if one is truly careful with what one eats, should stay away from the pure version as it is too processed, and should only use virgin coconut oil?

    Thank you. Miruna

    • Probably a 6th order term. (look up “ordered terms” in the glossary)

  • Richard S.

    Thanks, Martin. I see your points.

    And to all…I’m embarassed that I got so excited about the study that showed a lower insulin response with higher fat meals. That could easily just be the substitution effect. (Since the calories for each meal were fixed and fats cause no insulin response, then of course the higher-fat meals will have a lower insulin response. That could be just because, or mostly because, those meals also have fewer carbs and proteins.)

    Peter, many of us often lament the fact that there are too few good studies done about the topics that we are most interested in. And I know researchers are always looking for meaningful topics to study. It would be interesting to see a list of the studies that you would most like to see done, grouped by topic and priority. That would certainly promote good discussion, and with your growing clout it might help get those studies done.

    For example, I’d like to see a good study done on this point, where subjects eat protein alone and their insulin response is measured. Then they eat the same amount of protein with fat, and their insulin response is measured. Seems simple enough. If we listed proposals like that somewhere, then perhaps others would take some of those ideas and run with them.

    Thanks to all.

  • PaleoDave


    I am wondering if you think that the small amount of Corn Syrup Solids in Better Than Bouillon could drive insulin and suppress ketones in the blood. I have been following Paleo strictly while using Better Than Bouillon about 2-3 tsp a day for sodium. Blood ketones remain at .2 to .4. Eating about 85/15/5 daily with calorie deficit of about 500-1000 depending on exercise. Frustrated!


    • Minimal impact, I would guess.

    • 85/15/5 and blood ketones 0.2-0.4?

      You don’t say which of the numbers refers to which macro-nutrient, but I’m thinking given that A. your ketones are low and B. you’re called “PaleoDave” that you mean 85% protein, 15% fat and 5% carbohydrate. And that’s probably your answer. Way too much protein, therefore glucogenesis in the liver and you’re not generating or fuelling on ketones. Reduce the protein, increase the fat, good calculator here – http://sweetgeek.net/food/protein_calculator.html

      If you meant 85% fat, then I’m stumped.

  • Amanda J.

    Hi Peter,

    First off, I want to say that your recommendations have changed the course of my life. I’ve been a type 1 diabetic for 23 years and for the past several years, I checked my blood sugars dozens of times a day, ate a ‘healthy’ diet, and exercised regularly, yet my A1C’s always lingered around 7. During this past year, I started a low carb diet, and for the first time in my life, my A1C is 6.0. I have never felt better. I don’t even know how to begin to express my appreciation.

    Secondly, I have a question for you– I am getting treatment for a binge-type eating disorder. As you can imagine, this issue has wreaked havoc on my blood glucose control in the past. Things are much better on the low carb diet. However, I often feel the drive to eat past the point at which I am full. To try to prevent weight gain, I eat mostly low carb veggies at these times. Despite the intake of these low- carb and low-density foods, my blood sugars spike exactly as Richard Bernstein, MD describes as the ‘Chinese restaurant effect’ (the increased volume in the stomach causes stretching which signals receptors to increase glucose and/or insulin production/release). Therefore, I end up giving a larger bolus of insulin despite only taking in a limited number of carbs and calories. My question is this: when I give larger amounts of insulin, but eat a small number of calories (lots of low carb veggies), will I be more likely to gain weight than if I were to eat a larger number of calories (a high-fat, high-calorie, almost 0 carb meal) but give a smaller bolus of insulin? As an example, on a ‘low-density’ day, I give a total of around 30-35 units. On a day that I get about 30% more calories, but mostly from fat, I give a total of around 25 units.

    I realize that this specific question has probably not been addressed by studies, but I’d love your input on the subject. Thanks again for all of the excellent posts and for your work at NuSI!

    • Amanda, congrats on your great progress. I’m glad you’ve found the work of Bernstein. I don’t know the answer to your question. Seems like it’s worth experimenting under the careful observation of your endocrinologist.

  • Kamil

    A thorough series, Peter, good work.

    First, for the record:: by no means am I afraid of (healthy) fat. (My nutrition follows the one described in Paul Jaminet’s excellent book ‘Perfect Health Diet’).

    However… Maintaining the body in a ketogenic state requires an extremely restrictive & unnatural nutrition (please, don’t tell me, that rejecting to eat a banana or adding coconut oil to coffee instead of a full-fat milk is something Mother Nature wants us to do). The short-term (3-6 months) results may be promising, admitted. But this means NOTHING long-term, really. Have you seeen the results of this 60-day 100% carb experiment?


    How can you explain excellent blood markers and 21pound weight loss by eating the insulin-spiking starch-loaded potato?

    The goal here should be to strive a sustainable, affordable, enjoyable diet/lifestyle, not some hacko-experiments involving putting butter on full-fat chees for taste.

    Half of the World’s population (Asia & surroundings) lives on a high-carb diet and also happens to be among the healthiest on the Planet. Something’s clearly wrong here with a blind high-fat praise.

    I am lookking forward to seeing you addressing these nutrition questions.

    • Kamil, N of 1 experiments, including my own, are interesting any may generate hypotheses, but are by no means conclusive. My wife, for example, could live on M&M’s, Oreo cookies, and ice cream for 60 days and not gain an ounce (she has no weight to lose and is constantly trying to gain weight — unsuccessfully). You question about Asia and other parts of the world has been previously addressed on this blog. Should be easy to find, but I forget the exact title.

      Lastly, I’m confused by suggestion that I’m suggesting everyone should live in a ketogenic state? Are you taking this message away from this post?

    • Kamil

      Hello Peter,

      I do know your ‘Japanese phenomenon’ blog article (especially the honest ‘I don’t really know’ part, which is true – we have no idea why, and it would be extremely beneficial to find out the answer).

      Coming back to the ketogenic diet takeaway message: correct me if I am wrong, but it seems you are strongly in favour of a very low-carb, high-fat diet. Maybe you are right, maybe not, time will tell. But, for the NuSi project, one needs to reset and start unbiased ;), whereas all we hear so far is Gary Taubes’ high-fat appraisal and demonization of fructose.

      Paul Jaminet describes how reintroducing safe starches cured him from illnesses he had developed by following a strict LCHF diet. A topic worth investigation in the ketogenic series 😉

      Good luck!

      • NuSI is completely unbiased. Peter and Gary don’t do the research. As you say, time will tell. So until then, each of us needs to make up our own mind and do the best we can with current information. The only thing I know for sure is that Peter Attia does best without many carbs in his diet. That’s it. If your plan works for you, great. Paul is a thoughtful guy, and I don’t doubt what he says worked from him. But I’m not Paul. And he’s not me. Separate what I say population-wise from personally.

  • Nigel

    Many thanks indeed for your detailed and thorough work Peter.
    My wife and I are currently experimenting with a low carb high fat diet. We have rigorously monitored kcal, protein, fat and carbohydrate intake daily for two weeks with weighing food and a spreadsheet, itself a very interesting insight and worth the time. We have measured blood ketones for the past week. My wife is age 44, weight 57 kg, exercise active, healthy. Average daily intakes for her last 7 days: 990kcal, 50g protein, 95g fat, 12g carb, well satiated. To cut to the chase, her ketones are consistently between 5 and 7, which are too high for optimal ketogenic state as I understand it. I take it from some of your previous comments that such levels are not of great concern but I am still a little unclear on how the insulin response to such levels is not counter productive to the very effects intended with ketogenic adaptation? I have not been able to find much on it apart from a few comments attached to your blogs. Appreciate the volume of e-traffic you must orchestrate daily, so any brief advice you have would be most gratefully received.

    • I would say, assuming you’re measuring blood ketones in the units of mM, this is the upper limit of what is typically seen, though it’s probably explained by her relative hypocaloric state. I’d say keep it up and be sure you’re following the guidance of Phinney and Volek (e.g., electrolyte replacement).

  • Jim Small

    Was in doctor’s lounge talking today about a 5’4 patient 300 lbs, trouble with Metformin, on “diet therapy” for years. I asked about low carb and the discussion began. One doc asked around if anyone had any Atkins patients who had stuck with it for a year and everyone said no. he said all his Atkins patients had rebounded, regained all the weight plus more.

    Not a bad discussion actually but what came out was a big issue in the real world with compliance. There is a whole psychology here overlayed on the actual physiology of ketosis. The same doc said his patients got “mean as snakes” when they were ketotic, which does not match my experience in any way. But he is a busy internist in the modern era and certainly does not have time or resources to help people through the adaptation phase.

    There is nothing unique about a low carb diet by the way; ALL diets seem to fail down the road. One study on Medscape showed that ongoing support led to better sustained weight loss, which should not be a surprise. But it seems logical to me that part of your NuSI study design should include counseling, support, etc on all arms of the study groups.

    • Completely agree. The question is WHY is long-term dietary compliance so poor? I believe there are 2 drivers:

      1. Mixed messages from surroundings (family, friends, doctors, media) that discourage the approach (this is largely true of folks on low carb diets).
      2. Poor surrounding infrastructure. How tough is it to eat in accordance with a diet (low carb, again, being a great example, but not the only one), when everywhere you go dietary offerings (e.g., stores, restaurants, other folks homes) are completely orthogonal to your “prescription?” It’s the rare person who can, in the long run, stay on the prescription, despite the forces to derail.

  • Jessica

    I’d like to do my own experiment, so my question is: How long (how many days) would one need to go <50gCHO/day to get into ketosis? I'm a well-trained endurance athlete, and I'm training for Boston right now. My diet is about 55% CHO, 20% PRO, 25% FAT. I consume way too many simple sugars, which is a no-brainer to reduce, but I'm not convinced I'll feel better if I eliminate all CHO. I am thinking of doing a track workout (mile repeats x 5) and long run ~18 miles at a certain pace), each on my normal diet and each in ketosis. So how long will it take to go into ketosis from my normal high CHO diet?
    Thanks for all the information you're putting out there.

    • Typically, assuming all other kinks are worked out, only a few days. The adaptation (i.e., return to same level of functionality) can take weeks. For some, it’s 2 weeks, for other, like me, much longer. Generally, the more active, the longer it takes. It took me about 3 months to adapt.

    • Hemming

      Hi Jessica,

      Being very active myself I’ve also experienced that it takes a long month. It took months for me too. Anecdotally what really helped me was starting a food log, keep the carbs very low, keep the protein moderate (it surprised me how much protein I was actually eating), stay hydrated (this made a big difference for me) and supplement with sodium, potassium and magnesium (especially sodium). Besides that, read The Art And Science of Low Carbohydrate Performance by Phinney & Volek and remember their advice “when in doubt – eat more fat”.

      Good luck!



    • Ilya

      On the same topic, let’s assume you went through 3 months of no carbs and became very adapt… but then you have a week of weakness that consists of a very poor diet. Does that essentially reset the adaption clock, or will it take less than 3 months to get to the same level of adaption?

      • I don’t think so, but this level of nuance has never been studied to my knowledge.

  • Just wondering the following: when in ketosis, are fatty acids still converted to Acetly Coa for the krebs cycle, or is it all converted to Ketones?
    Also, do you know if you are on a low carb, but non-ketosis diet, say around 100 grams of carbs a day, just enough to provide your brain with enough glucose, what will the rest of your body use for energy?

  • Great stuff Peter….. I love reading through your posts and all your comments.

    – Dan

  • Great blog Peter and I love reading your posts and studies.
    Wondering your take and experience on these issues that are often associated or reported with a VLC diet?

    Dry eyes
    Not having enough glucose to form mucus in the eyes. Also continuing a diet with near 0 carbs likely suffering gut permeability issues when running out of mucus to protect the lining of stomach from stomach acid.

    Poor sleep
    The brain starving for glucose and making sleep tough.

    Thyroid issues.

    Extreme low-carb diet raising LDL levels.


  • Mike

    Hi Peter,

    I’ve been doing LCHF for awhile now and have had a great experience. Prior to this I was low carb, high protein and thanks to you, Phinney, Volek and Rosedale, I went ahead and dropped my protein down by about half and started proactively adding in more fat. I was never fat phobic to start with, but the exercise of bumping it up significantly and having nothing, but positives come of it was a pleasant surprise and has opened up a great deal of meal options for me. I know from previous posts of yours that you are very familiar with Dr’s Phinney and Volek’s work, but I was wondering if you we’re familiar at all with Dr. Rosedale’s work. I only recently came across his work and found his perspectives to be very interesting and found that he shed light on other aspects/benefits of a low carb, high fat, moderate protein approach that I’d never heard mentioned. Particularly with regard to the broad influence of leptin in various maladies, but also in regards to mTOR. I come from a weight training viewpoint and have been bombarded for years now with the whole idea of the growth promoting effects of mTOR up regulation, and the benefits of post workout protein consumption used to help stimulate it as well as eating above threshold protein intake on a per meal basis to keep restimulating it. Dr. Rosedale is the first person I’ve ever heard come out and say that this is likely a bad idea in terms of overall long term health. After hearing out his views on the matter I gotta say that it makes a ton of sense to me and have now shifted my focus onto improving hormone signaling via improved sensitivity rather that high signaling levels. Something i was already doing with regard to insulin sensitivty, but now I’m finding more of a reason to not go protein crazy than just knocking myself out of ketosis. So far, a month into it I feel nothing but better. Currently 193 lbs and 11.3% bf at 6′ tall, counting only protein grams(average 85-100 grams per day) keeping carbs low and letting fat satisfy hunger. Still making gains in strength while getting leaner. Also, seem to be getting even better results than I used to despite training infrequently. Im attributing this to improved protein economy due to a slower turnover rate associated with sub mTOR stimulating protein doses. I could be totally wrong about that part though, just my gut feeling. I’m curious to hear your thoughts on my experience and Dr. Rosedale, particularly with regard to mTOR as this was the part that was completely new to me.

  • Peter, firstly congratulations on a great website sharing all your experience and results. I’ll keep this brief as I want you to answer my questions…

    1) Do the less saturated dietary fatty acids, such as PUFAs, get oxidised preferentially over the saturated dietary fats? This would make sense in view of their differing shelf lives and susceptibility to peroxidation within the body.

    2) To what degree is ROS production reduced in KN compared with a standard diet?

    • 1. Correct.
      2. Has not be clinically tested, to my knowledge.

    • Hemming

      As a follow-up question to 1). Does that mean that PUFAs are less likely to be stored as fat or just that oxidised preferentially to SFAs? I’m thinking that in the first case the SFA/PUFA ratio matters and in the second it doesn’t. Either Paul or Peter, do you have a view on this?

      Best regards,


  • alice russell

    I find this subject fasinating. I am in ketosis and feel great. Stilll loosing weight but am very near goal. have lost 50 pounds sinse may 2012. started low carb and progressed to ketogenic diet around Oct. 2012. I am introducing more fat to my diet now and plan on living LCHF in weight maintenence. Full life with work, famlily and fitness regime; boot camp.
    Was high fasting sugar/hypogylcemic and now have stable sugars on the low end , stable moods and stable energy. my low iron issues are also resolved with this diet.
    I have recently read The Art and Science of LC Lifestyle and have a better understanding of the importance of salt and pottasium when eating LCHF.
    One resaon I can really see is that without eating any processed foods the only sodium I get is the sodium I physically add to my food. I have heard that as much as 5 grams of sodium a day is recommended. I have to admit that when iIstarted adding more sodium is when i felt 100 percent all the time. It was the missing piece for me.
    What are the other reasons for needing more salt or do you agree that 5 grams of sodium a day is needed when on a LCHF diet?
    love this blog and love this life style.

    • Severe carb restriction results in the kidneys excreting much sodium. Not replacing the sodium can leave many people feeling light-headed.

  • Jen

    Hi Peter,
    What an informative site!! My husband and I are considering lowering our carb intake. My only issue is that he (my husband) has had a couple of gall bladder attacks (he has “sludge”) and it was recommended that he limit fat intake. He does belch a lot after some meals, othertimes, he’s fine. The doctor recommended removing the gall bladder, which we were not intersted in pursuing. The high fat content of this style of eating is slightly concerning given his issue. Are some fats more difficult on the gall bladder than others? We are having trouble figuring this one out and would appreciate any guidance.
    Thank you!

    • Sorry, Jen. I can’t provide medical advice.

  • I have been treating my 30 y/o daughter with ALS since 2007. The primary pathology in ALS is cells lack energy hence it is a metabolic disease. The patients, as in most neuro degenerative diseases, accumulate Glutamate. My hypothesis is since Glutamate accumulates its breakdown products are absent. One of the breakdown products is AKG [alpha ketoglutaric acid]. This is the basis for the Deanna protocol now over 1000 patients world wide have requested the protocol and most of the responses indicate that it stops or slows the progression of the disease. Symptoms such as fasiculations, twitching and tremors are reduced or absent. My daughter tried B-H-B which made her symptoms worse. Pyruvate had no effect on her.
    My question is since AKG plus complex 1 precede B-H-B would not utilizing AKG or Pyruvate supply more energy than B-H-B ? Any thoughts why she would get worse as manifest by an increase in symptoms when taking B-H-B?
    I also would appreciate any thoughts of how I might enhance energy delivery to the cells? At present we have no way of measuring blood levels of AKG hence I have no way of knowing whether sufficient energy is available when needed. My supposition is that the dying cells emitting abnormal potentials cause the muscle symptoms. We know that when energy is provided to apoptotic cells the mitochondria lose their crenelated appearance and become straight. Hence it is assumed that the abnormal energy potentials diminish when sufficient substrate is supplied to the cells? Your thoughts would be greatly appreciated.


    • Vince, this is certainly the theory being explored with Veech’s ketone esters. Pull the papers I cite and you’ll see he comments on ALS as one possible disease that could be treated by ketone esters due the bypass of PDH and the supply of BOHB into the Krebs Cycle. The important question — to which I do not know the answer — is if a ketogenic diet can produce the same effect. This is important because ketone esters are not yet commercially available, unfortunately.

  • Noel-Holly

    Hi Dr. Attia,

    I thought I sent this question in but don’t see it so forgive me if I am repeating myself. Great information here it helps me to understand ketosis better. My question is is there a problem with cycling in and out of ketosis? For example I eat VLC/HF for fat loss but I find I want to up my carbs a little every 7-10 days or so. I assume this throws me out of ketosis, are there any potential health consequences from cycling in and out of ketosis regularly?


    • I don’t really know. Not sure anyone does, but it strikes me as a bit inefficient. Paradoxically, this may be better for weight loss, but worse for performance.

    • Carlo

      Hi Dr. Attia,
      Could you elaborate a little on how and why that is better for weight loss? Great blog btw, I’ve been following you for a little over a year after finding you through Gary Taubes’ site and I am a huge fan of what you all and what you are attempting to do!

      • I have no idea what you’re asking. What is “that?”

    • Carlo

      Sorry about that, let me clarify. I was asking a question in response to your response of the previous question about cycling in and out of ketosis every 7-10 days because of “cheating”. Its obvious why it’s not optimal for adapting and why it would hurt your performance. What I’m not clear on is why it can be more effective for weight loss? Especially in lieu of what was said in the post, that is that there can be an increase in overall RMR in someone who is in NK.
      Thanks again for your time Dr. Attia!

      • I have no idea if or why this is more effective for weight loss. I hope I didn’t imply that it is.

  • Zack Pianalto


    I was turned on to your blog/Gary Taubes/etc. a few months ago by a friend. Needless to say, I am consumed by it. While I do not yet have the details of all the science down, I am working to learn them. Obviously most people go into nutritional ketosis in order to lose weight/ be healthy/ promote fat oxidaton. I am an athlete and I am required to maintain a weight of around 250 + lbs. Since conforming my diet, in which I slip in and out of NK, depending on the day; sometimes I will eat nuts, sweet potato, occasional fruit, I have lost weight down to about 242 lbs. I would love to keep on this lifestyle change but cannot afford to be sub 250. Would you have any recommendations to keep weight on? I have thought about trying to eat more low-carb foods, thereby increasing caloric load. Or possibly bite the bullet and eat more complex carbohydrates. Any recommendations would be appreciated.

    Thank you,

    • Yes, certainly possible, but I can’t really answer in this brief context. So many variables and highly dependent on complete “suite” of goals and objectives.

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  • joe hutchison DC

    Dr. Attia,
    Do you have an opinion or would care to comment on the ability of Type 1 diabetics to safely enter NK? I have been type 1 most of my life, have been eating 20-50g carbs/day for almost 2 yrs. I have slashed my insulin usage approx 70% but still can not enter NK, I either have increased blood sugar and ketone production, indicating DKA, or I still have to take too much insulin to produce ketone bodies.

    • It requires great care and the oversight of a very experienced physician. With looking at the book Richard Bernstein, who is himself a type 1 diabetic.

  • Dwayne L.

    Hi Peter,
    Just when I get fully subscribed to the low carb lifestyle, along comes this kind of post from a nutritionist that starts me to doubt the central hypothesis:


    Particularly troubling for me is the overall insulinogenic index of foods and the tribes/cultures that eat high carb but have low rates of obesity. How do you counter these arguments?

    • Ahhhh…I wrote a lengthy response to this and then lost it. Short response: Stephan raises some interesting points. It might be that these cultures don’t have the high amounts of sugar and processed foods we do. As a result they are likely much more insulin sensitive and therefore able to tolerate complex carbohydrates better. Read my post on this. I think it’s called something like Why Do Some Cultures…

  • cimna

    Hi Peter,

    I’ve transitioned from four months of ‘lower carbs’ of about 100 per day, to under 50 with a small calorie deficit while following Phinney and Voleks suggestions. My fitness goals are in weightlifting and bodybuilding- I’m currently at 13-15% body fat and when I get under 10% I plan to go into a ‘bulk’ aka calorie surplus plus heavier weights to gain muscle. Is there any evidence or even explanation for achieving significant muscle growth if I’m sourcing 100% of those additional calories from fat? Bodybuilding forums are a hot mess on this topic so I’m coming to you : )

    • Scott

      Never got a response on this hey?

  • Tanya

    I have recently come across your website and am finding it fascinating. It is certainly difficult to explain to people what I am considering doing, when it is ingrained in us that fats are bad.
    I am currently doing a low carb, high protein diet which I guess is a step in the right direction. However, I have been trying to figure out what ratio’s I would need to adhere to (weigh 69kg, ideal weight is about 60kg).
    Also, in looking at potential diet plans, I was struggling with keeping the protein low with the fat high.
    Do you have any suggestions on the practicalities of keeping to a diet such as this?
    Many thanks!

    • I don’t think anyone knows (or at least I don’t). I find this much more empiric, and dependent on individual variation.

    • Tanya

      Ok, so trial and error essentially.

      Good news is I got some ketostix and I am officially in ketosis (but only just according to the scale, mid purple opposed to dark).

      Will keep trying!

  • ER

    Great work. Okay, honestly I had to read post a few times to get it, and I have a medical background. You did a wonderful job putting it altogether.
    Here are my questions related to ketosis and metabolism in general:
    1) can triglycerides be converted back to glycogen in the non-starved person? In your post on lean cultures, use you say that turning glycogen into stored fat is a one-way street. Yet into ketosis 101, you do say that triglycerides can be made back into glycogen in a starved person.
    2) reviewing energy you utilitization in exercising muscles – phosphagen system, glycolysis, followed by aerobic free fatty acid utilization – would a very lean person (on low carb 100-150 gm Paleo diet) end up in ketosis ( ie producing ketone bodies for energy), since they would have limited glycogen stores and not a lot of fat tissue to sustain exercise?
    3) please comment on physiologic insulin resistance – the state where your insulin is low but your blood glucose tend to run on the high normal side – in a fit lean person without metabolic syndrome. Since insulin is an anabolic hormone, is the low insulin a health detriment? Is high circulating glucose all day long a cell toxin in this scenario?
    Thank you.

  • ER

    So sorry, a follow-up question Peter.
    In ketosis 101, you said that in the absence of substrate (in other words no FFAs to be turned into Acetylco-A to go through the Krebs cycle) the ketone bodies are formed,. But if your diet is primarily fat, don’t you always have free fatty acids to make into acetylco -A and therefore you would not begoing into ketosis? I am sure that there is a readily available explanation in the material you wrote, but I cannot bridge this gap.
    Thanks again.

    • In the absence of glucose (turned into pyruvate into acetyl CoA)

  • JS

    Dr Attia – What’s the best post-workout food for optimal muscle growth while still preserving a largely ketogenic state? Can we make enough glucose from gluconeogenesis (via glycerol backbones of FAs or carbon skeletons of amino acids, e.g.) to trigger glycogenesis or do we need to consume carbs for growth? Seems like this process would be too slow (if it even happens) to allow adequate recovery after depleting muscle glycogen stores. Love to hear your thoughts – JS

  • ER

    How to begin….. your diplomatic rebuke, send me back to the books, and most importantly to a post which I neglected because I thought from the title that it would only lead me to product information (“Superstarch”). How I was wrong! I encourage all of the folks new to your blog to spend the time to listen to the embedded video – a wealth of information. I now see where my questions reflected my lack of understanding, my apologies.

    Can I still impose on you to answer the third question in my submission (dated March 9), in specific about physiologic insulin resistance in a low carb dieter? I never even knew such a condition existed until I read about it on both the Hyperlipid and Ketopia websites. I am trying to understand the mechanism by which insulin levels are low but glucose runs high through the day (increase A1C) in the non metabolic syndrome person – if you can supply the mechanism, I would be appreciative.
    Thank you for your time.

  • ER

    Hi Peter,
    I think there is no need to answer to my question about physiologic insulin resistance, it appears to me that all of the available information pertains to VLC ketoadapted diets, nothing to find on LC Paleo type, 100-150gms CHO/d. I did read the short term analysis – http://onlinelibrary.wiley.com/doi/10.1113/expphysiol.2006.033399/abstract – but really did not answer my query.

    My goal is to find a framework to understand the effects of a LC Paleo diet, so that I can recommend it to even T2dm patients (I’ve discussed it with nondiabetics, both lean and obese) and follow/understand their serum profiles. I cannot get support from endos and Diabetes Centers in the GTA – they all follow the Canada Food Guide, with lots of grains. I am not yet comfortable suggesting a ketogenic diet, without the support structure of the conventional medical community.

    I thank you for your patience with me, and your time, I am clearly frustrated with my inability to make inroads and appeal to open minds in the conventional medical community.

  • Hi Peter…. Hoping to get your thoughts on this:
    I was wondering your take on Dr. Jack Kruse’s blog on there being this PPP pathway (Pentose phosphate pathway) for superhuman performance. Using no or little carbs or a ketogenic diet among other things.
    Do you see merit in this and are you discovering this in your own training?
    I can see the fat adapt lower carb using fat as fuel for aerobic power and sustainability. How about in power athletes as well once fully adapt?
    Just wanted to hear your take on it.

    One of Jack’s response’s to my asking about it and how long it takes to see real results; “within 3 yrs you wil kill people if you stick with it”.

    Not sure how long you have been at it and if you are starting to see a switch in your anaerobic and strength power as well. I was told it takes 2-3 years to truly develop and be in this pathway to have the benefits of it.

    What is your experience and also applied not only to endurance athletes but strength, power and higher intensity performance as well. I just don’t see any world class athletes “yet” using this approach and smashing records or achieving great performance results.

    I am still trying to understand…. I know for you it is working great for an endurance athlete…. Is this the case for any athlete; power, endurance, HIIT, strength, etc. in your experience?

    Thanks in advance for your response…..

    – Dan

  • Thank you, Peter, for all this great information!

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  • Malinda

    I have been reading your blog and just recently started a ketogenic diet and I had a few questions. Is there any research, that you know of, that show a connection between endometriosis and a ketogenic diet improving the symptoms? Over a year ago I had to have an ablation done because of such heavy menstrual cycles (I lost nearly 3/4 of a pint of blood my last cycle). That effectively took care of the heavy bleeding and I have not had a cycle since….But before the surgery, I had been doing the endometriosis diet and had eliminated dairy, wheat, soy and red meats from my diet. When I did all that my pain was greatly diminished and I was able to see the correlation between my terrible hot flashes and mood swings to these foods, especially dairy.
    Now, this past week I’ve noticed something quite incredible. Last Sunday evening I began my ketogenic diet and it took me a few days to get the hang of it (I started the diet initially to lose weight). Within 48 I was experiencing terrible ovarian pain and the area was quite tender to the touch but as soon as I upped my sodium intake and added some potassium rich veggies that soon subsided. By the time I reached ketosis, the pain had totally decreased. But what was more interesting than that was I decided to try some dairy and some red meat since I was running low on groceries. I figured dealing with a few hot flashes wasn’t that big of a deal as long as I could keep on my ketogenic diet until I got to the grocery store. What I found out is that I no longer have the hot flashes that usually follow the consumption of these foods. I guess I should mention I’m only 34 and I’ve had two children with a total of 7 pregnancies. I currently weigh 160 pounds and I’m 5’9 ( I lost anywhere from 5-8 pounds this week….I never weighed myself before starting the diet and only began to weigh myself a few days into it). I’ve had no other health issues and no doctor has ever brought to my attention any issues when I had blood tests performed.
    I’ve been looking everywhere on the net to see if other women have experienced relief from a ketogenic diet and if there are studies to back it up. When I went into surgery, over a year ago, my doctor wanted to do a hysterectomy and I refused. I just want to make sure that I never have to take that route and I know diet is a giant contributing factor to endometriosis. So any information you could send my way would be fantastic!

    • Sorry, Malinda, I’m not knowledgeable on this topic.

  • Tyrone

    Hi Peter,

    I read here that ketones can’t completely replace glucose as an energy source for the brain:


    I assume this is why it’s necessary to maintain blood sugar within a homeostatic range. If this is true, what parts of the brain absolutely need glucose to function?


    • Tyrone, I’m not sure if it’s true that the brain can’t subside on B-OHB alone, but a better point is that we never have to, even in complete starvation (TG –> FFA + glycerol; the FFA get turned into B-OHB; the glycerol into glycogen). So the point is sort of moot. We always have some glucose for our brain. In complete starvation or significant NK, the balance is 50/50 +/- 10% either way.

  • Looking for a little advice, I’ve been in Ketosis for over 2 weeks, urine ketones and blood tests all consistent with Ketosis. But I’ve GAINED weight! I feel good, my waist is already looking good, brain fog gone…I attribute all to my beneficial diet changes. Hope one of you can give me some reassurance.

    • Can’t troubleshoot this way. Hopefully Part III of series helps.

  • Charles Grashow

    Dr Attia

    Did you ever get an answer from Dr. Westman to these questions

    “The question we don’t know the answer to is if an LDL-P of 2,000 in someone who eats no carbs is the same as an LDL-P of 2,000 in someone who does. I had breakfast with Eric Westman today and we discussed this topic. Eric makes a pretty compelling case that these 2 states are not, in fact, the same thing. I think we can safely say we don’t know the answer. At least I don’t. I’ll keep looking for clues, though.

    I completely agree with Eric’s assertion (in fact, I’m having breakfast with Eric in an hour). This brings up a much larger question that I’m sure I will detail more closely in this series: It is possible that all of the risk stratification we have for heart disease is predicated on someone consuming a normal Western diet? Furthermore, is it possible that once the body stops relying on glycogen and turns over to metabolic pathways of ketosis that the “numbers” we target as “normal” are irrelevant? I think I know the answer for some physiologic parameters, but I’m still trying to develop my “universal theory” uniting it all.”

    We are extremely curious.

    • Still be “hotly” debated in this circle. This will be covered in Part X of the cholesterol series, I expect.

  • Jeff Webster

    Hello Peter,

    The work you are doing is truly inspirational. I’m a 22 year old from London, UK spreading the word on Low-Carb (to those who listen of course).

    Anyway, I would just like to say I adopted the Low-Carb lifestyle back in September 2012. I have become an absolute advocate. I feel so good and my concentration levels are unbelievable (sitting my finals at University soon so that’s helpful). I would like to share that I conquered the London Marathon 2013 (4 hours and 36 seconds) and all of my training and racing was done low-carb. There was absolutely no carb loading, lucozade, gatorade, gu or gels involved whatsoever! I had my daily egg,bacon and avocado on race morning. I consumed a packet of Superstarch 45 mins before the marathon ( 26g carbs or 110 calories) then another pack during the marathon from around mile 10 onwards. I didn’t hit a wall.. I didn’t crash and burn like many people expected me to. I powered on through with only 52g of carbohydrates (220 calories) in the form of Superstarch . A calories deficit supposedly in the region of 2400 calories. Fat burning machine?.. Yes sir, I sure am!

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  • SPOgrydziak

    Recently discovered your web site. It is extremely well done.

    Please consider adding a section covering references; particularly with respect to books.
    I realize that you embed references/links in your essays; however, in some instances particularly when authors have multiple publications, a bibliography would be helpful; e.g., Phinney and Volek … yes but which of their books?

  • Jonny S

    Hi Peter,
    I absolutely love your insightful posts. I’m a middle-distance runner myself (800m-10km) and currently just training my aerobic system with easy,slow running whilst recovering from achilles tendinopathy. I wanted to ask you whether you think adapting to ketosis and utilising fat as fuel during my base training, before eating more carbohydrates prior to and post-competition would be a good idea? I’m 18 years old and just eat an unprocessed, balanced diet, but want to eschew grains and trial the ketogenic diet. How long would you say it takes to fully adapt?
    Thanks a lot Peter,

    • Hard to say without knowing much more. Full adaptation takes a while, probably on the order of 2-3 years if my experience is representative. The tough thing with your events is the span from pure glycolysis in the 800 to pure (just) sub-threshold in the 10k. Former is not likely helped by ketosis (except for the aerobic base work in training). Latter is likely helped quite a bit.

    • Hemming

      Hi Jonny,

      FWIW, I think you should look at Jack Kruse’s work on cold thermogenesis to further enhance your adaption and performance.

  • Kristine

    I have a question I am hoping you can help me with. I am a 41 year old female, with insulin resistance, PCOS and hypothyroid. I am obese with around 40kgs to lose 😮 I have been following LCHF for a few weeks and have lost 4kgs. My daily macros are around 1400-1500 calories – 75% fat, 20% protein, 5% carbs. I eat no grains and no refined sugar (very, very little rice malt syrup or coconut sugar). Ketostix show i am in ketosis. My question….Around 12 years ago I had my gall bladder removed. It suddenly occurred to me that the LCHF diet might not be for me because of this???? It would be great if you could help me out with this. Should I be making allowances for the fact I have no gall bladder?? Many thanks in advance!!

    • It may require eating less fat in one sitting, since the GB is a reservoir for bile. But it does not diminish your ability to produce bile and emulsify dietary fat.

  • Andrea

    I’m new and catching up, I missed what TEE means can someone please define for me? It would go to a long way in understanding this article. Thanks so much!

    • Sorry, means total energy expenditure. I think I defined these terms the post “Good science, bad interpretation.”

  • Tom Hughes

    I have a question that you may or may not be able to answer. On the ketogenic diet you have to replace more salt. It is logical baby that the Renin-Angiotensin Aldosterone system would be working overdrive? Particularly in the morning before my Bouillion?
    The reason I ask is because I take my heart rate variability every morning. I analyse it with regards to VLF, LF and HF. Since I have been ketogenic I have noted a very very high VLF component, in the literature this is believed to be related to activity in the RAS. Does this logic make sense? Could this indicate I need more salt to calm my RAS down?

    • Yes, it’s possible, in the absence of sufficient salt that RAS is working hard to preserve sodium, though there seems to be adaptation to this over time. I rarely require bouillon any more, though I once couldn’t get through the day without it.

  • Julie

    I found some disturbing info on the dangers of alcohol and ketosis here- http://sun025.sun.ac.za/portal/page/portal/Health_Sciences/English/Departments/Biomedical_Sciences/MEDICAL_PHYSIOLOGY/Essays/Post-exercise+ketosis
    Is there any reason this would not apply to people in NK?

    I find many references to people becoming a “cheap drunk” while in ketosis. I have also heard others talk about passing out or blacking out after 2-3 drinks. Would this explain the phenomenon? I think more people need to be warned about this. I had to stop drinking after a black out episode that scared me enough to look into the “cheap drunk” biological mechanism.

    • I have heard this also, anecdotally, but I’m not sure this explanation is correct. Regardless of the extent of NK, there is always more than enough glucose to meet about half the needs of brain and other cells like RBC. So this theoretical issue he points out is not a real one. The issue of being more impacted by ethanol while in NK is interesting. If the issue is driven by EtOH inhibiting gluconeogenesis, I would expect symptoms of hypoglycemia, which are noticeably different than inebriation.

  • Julie


    The only other explanation I can find is the the metabolic pathways of ethanol and acetone share the the ADH enzyme and the production of that enzyme has been upregulated in NK so one is able to digest the alcohol faster to its toxic metabolite, acetaldehyde.

    My 300 lb, LC neighbor had 2 rum and diet drinks and had to be helped from the front porch to the bedroom. Two drinks in a person this size shouldn’t have that effect. After my experience, I have to think it is because of our ketogenic diets. Any other ideas??

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  • Holly Reardon

    Hello Peter,

    Thank you to you for sharing your story and educating those who care to learn. I saw a post above where you mentioned that there are those on the diet whose bodies react differently to dairy and to alternative sweeteners such as Stevia. I have been on the LCHF diet for about 3 weeks and can’t say that I have lost weight – and I too am experiencing exhaustion. I can and will tough it out for the greater good – but was wondering if maybe I too am eating too much protein… a symptom of the Zone diet which I lived for about 20 years – or if the dairy is the culprit. I really just want to be leaner. I have also noticed a few people who mention VLC? Is there a suggested phase of lower calorie? I am thinking that I will cut out whole raw yogurt and stevia as these maybe inhibiting my lean-ness. Any insight would be greatly appreciated. Tips on fighting the exhaustion would be awesome too!!

    Thank you again for sharing you story and for this forum!



    • Could be, Holly. See the book by Phinney & Volek (the art & science…). Very good reference.

    • Holly Reardon

      Thanks Peter – will do!!

  • Rob W.

    Dear Dr. Attlia,
    I am very impressed by your web site and all the information contained here. Thank you for investing so much of your time and passion into this. I was wondering about ketosis vs. fatty acid oxidation in the muscles. Is there a reason that the liver produces ketones to support muscle function when mitochondria in the muscles can oxidize fatty acids as well? Is ketone oxidation somehow more efficient?

    Thank you again for all of this excellent information.

    • I don’t *think* that’s it, Rob, but I could be wrong. FA and glucose enter the mito via different routes, and I suspect the ketoadaptation process is more about an alternative to the glucose pathway.

  • Samuel B

    Perhaps I missed this in one of the comments, but I just had an interesting change after going on a ketogenic diet. I was mainly interested from the stand point of sports performance. I am a 66 year old male, who likes to cycle long distance. I bought a test device and after lowering my carb intake to between 20-40g per day I measured my beta hydroxy butyric acid, and it would vary from .3mmolar to 3.3 mmolar depending on time of day, and what I did. The very high value was after riding 60 miles.

    Here is a before and after snapshot of my lipid profile. Pre-ketogenic diet at about 100g of carb per day these are the lipid values, LDL-P 1300, LDL-C 129, HDL-C 103, Triglycerides 48. LDL size 21.2, LP-IR score 7

    After three months on the keto diet at about 20-40g of carb per day the lipid values are LDL-P 1471, LDL-C 162, HDL-C 95, Triglycerides 44. LDL size 21.3, LP-IR score 3.

    The LDL-C spiked and I did not expect that. Here is one possible explanation, http://www.lecturepad.org/index.php/lipidaholicsanaonymous/1140-lipidaholics-anonymous-case-291-can-losing-weight-worsen-lipids
    One thing that is interesting to me here is that you cannot explain the percentage change in mass concentration of LDL with the change in particle concentration and particle size. Something else is going on (particle composition?).

    What is your experience? I certainly felt a lot better cycling on the keto diet. The synthetic starch worked great. My A1c has always been 5.4. Before buying the test meter I did not realize that fasting blood sugar depended on the time of day. Mine starts off in the low to mid 70’s in the early morning and peaks out in the mid 90’s about mid morning (this is with no food consumption). I don’t know what this is good for unless you show up with a fasting blood sugar at 50 or 150.

    I did not stumble across this lipid change in Volek and Phinney. Any thoughts would be appreciated.

    • The difference in LDL-P is within the range of testing variance (easily +/- 10%). The difference in LDL-C is not of clinical consequence, though suggests on average your particle size may be larger (not reflected in the size number they calculate).

  • BC

    Dr. Attia,

    Thank you for your sincere desire and commitment to research and understand this issue and work to promote solutions which save lives and promotes good health. Keep searching for the answers and striving to make things better. The problem seems to be getting worse daily.

    I was inspired to find you because of your TED Talk. I read this entire two-part post, so I’ll forgive your length of content if you’ll forgive mine. =)

    First, I have to say I was disappointed a bit. From your TED talk, it seemed you were newly embarking on a quest to find and help solve the obesity problem. Seemed like you were searching for answers and would remain open-minded.

    Yet, reading this post and others, it seems you have already found many of the answers and are willing to readily dismiss others in the field who also have been sincerely searching for answers for decades. It also seems like posts like this are geared toward “fine-tuner” dieters and performance athletes. Rather than those like the obese woman you mentioned in your TED Talk. I appreciate that there are MANY conflicting studies, lots of technical details and subtle nuances to every issue. At the same time, was hoping to see a layperson summary on your site of the common prevailing wisdom, what you have found good/bad about what’s out there and simply concrete steps that everyone can take. Instead, seems like a conclusion has been reached “ketogenic high protein is the way to go” (my take on your approach) and anything that might go against that has flaws. Already, it seems you have taken an unmovable path? Hoping not and perhaps I’m misunderstanding?

    If not, perhaps you can invite someone like Dr. Barry Sears (whose study and work you seem to dismiss in this post) to have a debate or to guest post on this issue? If you are truly open to other views, wouldn’t you want your readers to benefit from hearing the other side of the issue? It seems many of your readers quote him — though also seems we are disparaged a bit as being in a “no camp”, so we’d all benefit from inviting him to participate.

    As a layperson and not a doctor or trained medical expert, I have been following these issues for 16+ years. I sell no products or services and have nothing to gain, other than improving my health of myself and my family.

    But in looking at this, I have found Dr. Sears’ work (decades long), to so far be the most accurate and reliable. He is certainly not part of the “high carb establishment”, but he’s also not part of the “high-protein” establishment either. His point seems to be, “If you can get the same of the benefits from a (barely) non-ketogenic diet, especially related to long-term health, why risk any short or long-term risks that may be associated with (highly) ketogenic diets”? I’m paraphrasing, and don’t want to speak for him, but that’s my take on it. I have come to respect Dr. Sears and not as willing to dismiss his work and theories, many of which probably align with yours, esp. related to keeping insulin levels in a “zone.” His work related to insulin and other hormonal impacts seems solid.

    You show studies and data related to short-term “performance” benefits (weight loss, physical performance), but are there studies that also show long-term effects of ketosis? Such as bone/muscle loss in women and the elderly (which seems a potential risk, does it not)? Hunter/gatherers and human evolution didn’t have to worry about breaking a hip at 80 or living healthy at 90 years, evolution just needed to get them to 30-35 years old–avoiding starvation, but also providing them skills to hunt, gather, fight rival tribes, raise their young, social skills, etc. They could probably have eaten anything with enough nutrients to live to 30. So not really the evolutionary “cause and effect” you said you’d look to find in the TED video. It’s just what and the way they happened to eat to survive. Seems as though dietary content/mix is not what made them survive? A ketogenic person could have been eaten by a bear as a non-ketogenic person.

    The question which I do not see addressed in this post (maybe I’m missing it?) is: “What do studies show about the long-term impacts (positive of negative) of a ketogenic diet? Esp. looking at bone density in the elderly and/or women?” If you have studies, would love to read them!

    Again, I do appreciate your work and am much closer to your view than the “high-carb camp.” But still skeptical of the “high-protein camp” as well.

    Thank you for reading/listening.

    • BC, you are misunderstanding. Do not confuse this silly little personal blog with my job. For a description of what I do “for a living” please see our website at nusi.org. Don’t worry, you’re not the first person to confuse my hobby with my job. I hope I can continue to blog for fun, but I do worry I will need to shut my blog down if such confusion persists. By the way, I do worry that you may be projecting something in your question. At no point in either of these posts on ketosis do I suggest everyone should be on a ketogenic diet, so I’m a bit confused by the nature of your questions which seems to suggest I have.

  • BC

    Yikes. Dr., I thought my questions were reasonable, based on my understanding of the ketosis issue. But forgive me if I offended you or didnt ask them in the right way. Im just a lay person searching for answers. If anyone else reading this, particularly anyone else familiar with concerns around ketosis and bone/muscle loss and the work of Dr Sears, perhaps you can translate for me or do a better job of asking the questions. Many of the comments and replies seem to be conversations related to optimizing performance via ketosis, so yes, I guess I am confused about your current thinking on the issue. But I see a few comments like mine, dismissed by saying you are not suggesting that “everyone” should be on a ketogenic diet. Should anyone? Is there evidence of long term benefits and/or risks of ketogenic states or not? Is it an “advantaged state”? Do you see merits in Dr Sears’ work or not? Seem like fair questions and dont seem to warrant threats to shut down the blog.

    • BC, perhaps another reader an elucidate for you the nature of your first question, and why such comments don’t sit well with me.

      To your question, should anyone be on a KD, the answer is yes. BTW – the “famous” Barry Sears paper that looked at KD did not have subjects in ketosis, despite claiming so. But you’ll need to read the paper in detail to appreciate this.

      Lastly, I have no idea why you’re confusing — utterly confusing — what I do for a living at NuSI with this silly personal blog. Why do these 2 states need to overlap completely? If I wrote a blog about cars or bikes, would that create as much dissonance?

    • BC

      which comment doesnt sit well? having someone say that content related to a serious health issue like obesity is a “silly little blog”, esp after your TED Talk, doesnt sit well with me. If you did a serious TED talk giving the impression your mission was to find the worlds best bike, regardless of your “day job” of searching for the worlds best bike, yes people might think your personal bike blog with lots of serious, in depth bike gear discussions was not “silly”. Perhaps its legal concerns driving the downplay of the blog on one hand, while getting serious with your own volumes of content and people who seem to agree with your conclusions on the other? why would the job of finding the truth about nutrition stop at work and not be in everything you do, including your personal blog about nutrition, where it seems you are already expressing conclusions from work in your day job?

      Have you contacted Dr Sears to hear his side? or only those who seem to agree with the conclusions you have already come to?

      I see you still avoided answering the question about any studies showing long term risks or impacts of KD -positive or negative-esp for women and elderly. that is my ultimate question for which I still see no answers.

      • BC, I don’t think we’re going to resolve this inability to see eye-to-eye. I guess it seems you have a choice: you can stop reading my personal blog, where I write about whatever I want, whenever I want; or you can be patient and wait until I address your concerns, which will happen in time. Please refrain from further comments on this particular thread, as I will no longer address them. Hope you can find something else on this blog that interests you.

  • Tom Hughes

    BC – Firstly I wanted to put a quick answer to your comments above, I think you have misinterpreted most of the information that Peter has provided via this blog. This, to me, is a personal journey taken by Peter as he investigates how this diet/lifestyle impacts on HIM. Now, what you take from that is up to you.
    Peter is a doctor, correct. So am I. I rarely use my title and I avoid using it with regards to this topic as I do not want to display that I am using it to influence others. Many people trust me (rightly or wrongly) because of my title, but I always try to project the fact that all it gives me is a slightly-better-than-lay knowledge of the human body.
    I can also appraise evidence better than most.
    I have found Peters blog fascinating as I have taken this journey myself, as I believed that it would enhance my health and athletic performance. In my mind it has done both. But what works for me may not work for others.
    Ok, now that is done I have some info for you Peter.

    I have noted a few things I thought you might like to know.

    You remember my comment about the VLF component of HRV being high in the morning, possibly related to RAS? Well, I did some testing, 30 mins after a cup of bouillon the VLF drops significantly. Possibly point proved?

    Secondly, I have been testing ALOT with blood ketones, particularly around training and carb intake. I was very very low carb for a long time (and have been low carb for 3 years now) and have been re-introducing carbs into my diet to test the effect. What I am finding is that I can consume very large amounts of carbs around training and stay in ketosis quite happily. I can also have huge huge carb binges (after a half ironman last week, nearly 800g of carbs consumed) and be in ketosis the next day.
    I believe this is the level of adaption my body has reached, meaning I slip back into ketosis very easily.

    The only thing that ‘knocks’ me out of ketosis is gluttony, whether its carbs, proteins or fats. But I am generally straight back in within a day at most.

    I thought you might find these comments useful, as it may help some of your readers appreciate that you maybe don’t need to be too ‘strict’ on yourself when you have achieved adaptation.

    Thanks again for your blog, it provides insight into these topics from a (hope you don’t mind me saying) analytical mind.


    • Thanks, Tom. You’ll have to refresh my memory on the VLF discussion. Excess protein and CHO will definitely knock one out of ketosis. Excess fat should not, but keep in mind, getting “excess” fast without protein or CHO is very tough.

  • Tom Hughes

    Hi Peter,
    I think its mentioned above. But in brief, I do my HRV daily, to check LF and HF components to aid recovery/training load. I noticed a trend since I started ketosis of a chronically high VLF component. The literature is still unsure what this component means, but possible explanations are the RAS, or thermogenic energy expenditure, as it seemed to correlate with methods to increase this in obese subjects.
    Both of these could be increased in Ketosis, due to the salt de-regulation and the thermogenic effect of the ketones.
    Anyway, I postulated that it was the RAS as it was first thing in the morning, prior to my bouillon.
    I did some testing, and true enough 30 mins post bouillon the VLF went from 80-90% of the power to ~60% which is what I would normally expect.

    On the second half of my comments, what I meant was that from my testing it does not seem to be about what you take in, in terms of carbs, proteins, fats, its when you take them in in regards to what your body wants and when.
    For instance today I did a 5 hour ride.
    The first 2 hours were water only, the 3rd hour was BCAA only, the 4th and 5th hour was Vitargo, a complex starch. I would use superstarch but I can’t get it over here in the UK (well I can, but its from spain and is incredibly expensive).
    Then, after the ride a massive bowl of gluten free porridge oats and coconut milk.

    Ketones before the ride 1.0, glucose 4.0.
    straight after the ride 3.0, glucose 6.1
    2 hours later, ketones 3.5, glucose 4.5

    So, the massive carb intake has not impacted ketosis because my body needed it.

    Conversely, I have very large, very fatty (~30g protein, very little carb) meals later on in the evening (when my body doesn’t need it) and my ketones have been 0.3 the next day.

    Hence my point about it being gluttony, at the time when your body doesn’t need calorie loads that knock you out of ketosis. I guess that would fit with the idea that ketosis is part of the ‘starvation state’

    • I completely agree with this, Tom. In fact, if you look at my 24-hour tracings of glucose and B-OHB in the presentation I gave here: https://www.youtube.com/watch?v=NqwvcrA7oe8 you’ll note the same thing. Replacing lost glycogen post-ride does not inhibit ketosis at all. This is why on some days I need to eat 100 gm of CHO, while other days only 30 gm.

  • calvin

    hi Peter

    thank you for all your efforts to help us understand in a scientific way.

    Three months ago I decided to try NK. This for a palette of reasons. I did not have any overweight problem, nor I had bad blood parameters, but this had a price to pay: never stop surveying what I eat and accept the idea that I had to stop eating before feeling satiated. Honestly, I cannot say that I felt full of energy. Furthermore, this way of keeping things in check requires efforts and generates stress; since we can tolerate a finite amount of both it seemed to me a pity to waste them in that way. I also liked the idea of not suffering cravings if I had to skip a meal (it actually happens in my working environment), the perspective of not bonking when running, cycling or mountaneering … you know all this. In the end, with few exceptions, I have never loved that much the carb-based foods and I wanted at least once to allow my taste to guide me.

    I must admit that all the advantages I have read in your posts and the associated comments are all there, so no reason to list them again; in a few words I have more energy and clarity of mind. I marginally lost weight, let’s say that I have shaved 1kg, now at 66. Overall, I feel much better. I only had two drawbacks, which turned into two questions I do not know how to answer.

    The first is that I feel much more affected by alcohol than before. Before going into NK I could drink a few glasses of wine and feel OK. Now, one glass is enough to make my head float. In absolute terms I guess there is nothing bad with this, provided I reduce the amount of wine w.r.t. before NK, but it is a bit unpractical since I am following a professional sommelier course. Silly, but … real, at least for the moment, so I have to decide if I better stop NK until the end of the course. So the question: is there anything specific in the interplay of alcohol and ketosis? I have read posts in several blogs but none of them looked scientifically solid. I have also seen comments on this same page, from which I conclude that it is a matter of debate. Correct?

    The second might develop into a problem, but for now is a curiosity. I decided to have a standard cholesterol blood test. I know that one should check more detailed parameters, but the standard thing is a fast and cheap cross-check with the same measurement I had done a few months before starting NK. I have been scared by the results, although I may simply have biased the measurement myself. I had a fairly normal dinner (moderate meat, cheese, salad with olive oil) the night before – admittedly with a couple of glasses of dry red wine. I hardly believe it could influence the test, though. No breakfast, of course. The morning of the test I woke up in auto-pilot mode and without thinking I laced up the running shoes and went for >1h running; aerobic pace, but still not a pleasure stroll. Let’s say 70% max HR. When I returned home I realized I wanted to take the test, so rushed to the lab and had the blood taken something like 30 to 60 minutes after running. The results were – to me – scary and hard to understand: TC 320, LDL around 200, TG 270. High TG on very low carb? Only HDL stayed where it was, around 100. I will take the test again without shutting the brain off beforehand, but this episode raised a question in my head and I could not find the answer. In my daily work a measurement is a measurement and it has to be understood; so even in this case, apart from claiming that the lab screwed it up, a bias – if any – should be explained and quantified, but not being an MD I do not have the knowledge to do so. Coming to the questions. If I am in ketosis (confirmed by testing myself) I am supposed to use fatty acids as the primary energy source. Right? So, does training in aerobic mode increase the amount of fats in the blood during activity? If yes, how would these fats show up in a test and how long do they stay around after the end of the training session?

    • Calvin, thanks for sharing.
      1. I think the alcohol phenomenon is a real one, and I’ve heard it from many folks. I am not sure exactly why, though I have to believe it has something to do with how the liver processes ethanol and makes B-OHB simultaneously.
      2. I’ve done a set of experiments I need to write out that looks at changes in lipoproteins as a function of exercise. It addresses this, but it will be months (years?) before I can get to it. To your first point in this question, Part X of the cholesterol post will address.

  • Klairamae

    Hi Peter,

    It appears that much of the research in ketogenic diets involves men. However, I have not done the extensive review of you and your colleagues. In your review of the literature, have you found evidence of gender differences in response to ketogenic diets?

    Thank you so much for your refreshing contributions to this field.

    • Great question. I agree that more work has been done in male subjects, but I have seen research in female subjects, also. You may want to check out the work of Hussein Dashti.

  • Nancy

    I have been on a ketogenic diet for 2 weeks. At first I felt great, but now I have headaches and muscle cramps. What should I be doing differently? I really want to continue on with this style of eating.

  • Greg S

    G’day Peter,

    I add my vote to the cheap-druNK concept. I’ve been NK for 7 months and I get hit rather hard by a couple of glasses of wine compared to pre-NK.

    By the way, thanks for writing your blog – I am an enthusiastic follower.
    And your TED talk was up there with the very best.

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  • Jason

    I just came across your website this week and am very excited to see someone else telling the truth about nutrition! I am a type 1 diabetic and have always been active and in relatively good shape. I have followed Dr. Richard Bernstein’s plan for close to 10 years now. The problem I have is that I want to remain in ketosis, but during training for triathlon and in the actual races, my blood sugar drops rapidly and I have to take a lot of fast acting glucose to avoid a major hypoglycemic event. So, how can I stay in ketosis when I have to take in 60 + grams of carbohydrate per race or intense training session?

    • One can stay in ketosis and consume more than 60 gm/day of CHO, if metabolic demands are high enough. On my most active day, with enough threshold work, I need to consume 100 gm of CHO per day to perform, and still remain in ketosis.

  • Joe

    Hi Peter!

    One question I am just really confused about is how can ketosis enhance muscular growth? I’ve been ketogenic and I have gained muscle but this surprises me. In the low-carb community there is much discussion regarding the role of insulin in fat storage but very few also mention that insulin also fuels muscle anabolism. Is it simply that insulin has a much less pronounced effect on muscle than fat? Do other hormones play a greater role in muscle growth? Type 1 diabetics, if left untreated lose massive amounts of fat and muscle. Shouldn’t their muscle be preserved if lack of insulin is the problem? I am very confused on this subject. Your help would be greatly appreciated.

    • Ketosis may not be the fully optimized state for pure hypertophy, but unlike T1D, a person in NK still has some insulin. Training specificity, and amino acid composition, and genetics, will all play a role.

  • Marion

    I am a woman of 74 years but I haven’t seen any reference to the effects of NK on the elderly. I have been on this diet for about 3 weeks now. have lost a couple of kilograms (I am slightly overweight) and feel fine. My cholesterol was a bit high. I’m not sure what it is now. However, my concern is that I have osteopenia and, in some parts, osteoporosis. Can NK harm my bones, i.e. cause loss of minerals? I take various supplements.

    • Really good question, Marion. I don’t know the answer, since I have not seen any studies implementing NK in the elderly. I think the best thing to do would be get a bone scan (DEXA for bone — ask your doctor for a referral), then repeat in 6-12 months, while continuing to supplement. Of course, the recent post I did should hopefully convince you that NK is not “necessary” to achieve your goals.

  • SOMK

    Hi Peter:

    Great essays and even more so very informative. I continue to reread them to get a better understanding of ketosis.

    Various references indicate the brain’s daily need for glucose being from about 120gm falling to 40gm or so once keto-adapted. When referring to the glucose needs of the “brain”, is this the entire nervous system or specifically the mass of the brain within the skull? Further, what is the amount of glucose used for the other areas of the body that continue to rely of glycolysis for energy generation even when keto-adapted, e.g., red blood cells, interior of the kidneys, and whatever else.

    By the way, your TED presentation was powerful. I found the virtues driving you as a physician and medical researcher even more significant than the theme of the presentation itself. For inspiration, I send a reference to the presentation to my nephew who is in a PreMed program.

    • Neurons depend primarily on glucose. The grey matter is one of the most metabolically active parts of the body, on a per weight basis. In keto-adaptation, the brain continues to get about 50% of its energy from glucose.

  • Marion

    Thanks, Peter. I was hoping that there had been some research done on NK and osteoporosis. I have been having bone scans every 2 years so will have another one soon. I actually went onto this diet mainly to encourage my husband, 78 years, over weight and pre-diabetic, to do so too. Do you think it will be good for him? He has only lost 1kg.

    • It probably is, if he has carbohydrate intolerance, which it sounds like he does. Consider reading Phinney & Volek’s book and that of Richard Bernstein.

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  • Darren

    Hi Peter,

    I’ve read about people having rashes (prurigo pigmentosa) in ketosis (nutritional, fasting, diabetes, etc.) where things like increasing carb intake and insulin administration helped (also antibiotics). The cause seems to be unknown, but some “theories” I’ve read are Candida die-off or a Herxheimer effect, and the body detoxifying/releasing toxins stored in fat. I would love to hear your thoughts about this!

    • Very interesting, though I am not aware of this effect.

  • Robert Patocchi

    I have a question. I lift weights and swim. I am 57 years old. I eat less than 30 grams of carbs a day. I don’t seem to notice a slow down at workout for my swimming workouts which the coach gives me ( Mostly anaerobic). Lifting weights do not seem to be hampered. When I sprint a fifty which might be equal to a 200 in track I do not find my speed dropping at all. So that is my experience with training. I have not swam the 100 lately. Would I be slower ? It is equal to a 400.

    Now about nutrition. When I had my whey shakes after workout I began to gain weight, I think body fat. I figured that it was because I was getting to much protein and it was knocking me out of ketosis. I increased the fat and dropped the protein and I stopped gaining weight. But then i read Mc Donald’s work on the keogenic diet. He says increasing fat does not effect ketosis. It is the amount of protein that can effect ketosis. And eating to much will knock you out. A lot of people recomand increasing fat. But if your protein is low enough and you are keeping the fat low will it effect your keto adaption???? (I mean I would do this to loose weight. )

    • Ketosis is very sensitive to carbs (obviously), but also protein (more than most people realize). I would guess that if your 50 speed is still there, so too will your speed in the 100, especially as you adapt.

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  • Andrew K.

    Good afternoon, Peter.
    I have mostly been in ketosis for the last year, ever since I decided to change my eating habits.
    Now, I am an avid coffee-drinker. Although some people agree or disagree about the effects of caffeine on ketosis, lypolisis and insulin resistance, I was wondering about your perspective on this compound, and the effects on the latter states mentioned.
    More importantly, does science point to mostly negative effects on caffeine, or positive?
    Thank you very for your time and contribution in the field of scientific nutrition, and I am looking forward to part III.

    P.S. I live in Montreal and I now have a wide field of knowledge in the subject after reading many articles by Taubes and yourself, to the point where I actually wrote a 15-page essay on the leading causes of obesity in the West, where I concluded that carbohydrates were mostly the cause, when combined with poor genetics. Essentially, I have enough confidence to go out and explain this metabolic state and its advantages, as well as the metabolic problems of a high carbohydrate diet. What can I do to contribute to the research and awareness?

    • Caffeine in most people probably increases sympathetic tone. This would drive up lipolysis (via HSL) and hepatic glucose output. Net result would probably raise glucose slightly.

  • EdR

    I have to thank you for this information. I am Type II diabetic and I have normal glucose. I have lost 50 lbs. I have an A1C last measured at 5.1. My trigs are 96. HDL 41. It has been over a year since my A1C was 8.6. Your information has helped me stick with it.

    Keep going. It will take some time for others follow your lead. But you know the statistics. It will be worth it.

    • Amazing story, Ed, especially when the convention wisdom says the following: T2D is a chronic disease that only be managed with medical (re: drug) therapy.

  • Austin Newsam

    Thank you so much for this series, Peter. As an undergraduate biology student I find this blog most interesting.

    Your knowledge is much in coordinate with this reading I just came across how ketosis can facilitate brown fat concentrations! http://www.nyas.org/Publications/EBriefings/Detail.aspx?cid=f2c6ffae-5166-4478-a01d-261c6742d2c2

    I would love to help out anyway I could with NuSI as an undergraduate, as I am a firm believer in the Alternative Hypothesis myself.

    • Thanks, Austin. Please direct any NuSI inquiries to NuSI.

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  • Kathy

    Can somebody…anybody please answer this question for me. I found where someone else had asked this question, but it was never answered, and I have spent many unsuccessful days trying to find the answer online.

    I want to do some tests (amending my diet) to determine what is keeping me from getting into NK. I have the monitor, I have the strips. WHAT I DON’T KNOW IS HOW SOON AFTER I EAT, WILL MY BLOOD KETONES BE AFFECTED?? PLEASE HELP ME =)

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  • Marion

    A 69 year old friend in England has terminal cancer. I read of a doctor who was given 3 months to live because of cancer. He went onto the LCHF diet and this got rid of all the cancer cells. My friend is now trying it and after a few weeks already feels she has more energy. However, she is loosing weight, which she can’t afford as she is already thin. How can she ensure she won’t loose? Then she has heard that this diet puts strain on the liver and that is where she has some tumours. I have not heard this. What comments or advice can anyone give please? It would be good if she could find a doctor who believes in NK.

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  • Niklas

    Thanks for sharing so much interesting stuff. I run ultramarathons 50 miles up to 48 hrs and have a history of “bonking” after 10-15 hrs of running/jogging/walking. My stomach cramp, energy drops big time and within an hour it’s like running while having the flu. I’ve tried eating a lot, eating not so much and eating different stuff. Nothing has worked out so far. So a week ago, after reading about keto-adaption, I decided to go fat 70% protein 20% and carbs 10% approx.
    First 2-3 days I could’ve killed for sugar but energy level was only slightly lowered (no running). After that my temper has stabilized back to normal and I’ve done some 1/2 hour slow runs. Energy level while running is still a bit lowered but in general on my base level.
    Now, today (on day 5) I took a lab. test on ketone in urine which showed 3+. The manual at the lab (wife work there) said 3.9-8.7 mml/l some sites on internet say 3+ = 1.4-5.2 mml/l. In any case it’s a relatively high level. My question is, if this is a true positive, can you really get that result from 5 days of keto-diet unless you had a rather high baseline to begin with? If that is possible and I’ve gone from a “normal” level of 0-0.5 in this short time shouldn’t my subjective experience of change be a bit more obvious. As noted I don’t feel that much different in any aspect, physically or mentally.
    For the record I’m 47yrs and diagnosed with adhd (treated w methylphenidate) and my staple food has always been much of everything, especially fast carbs.
    Anyways, I’m very surprised by the test result and eager to find out if I am (a) an anorectic alkoholic with diabetes, (b) a potential fat-burning machine par excellance or (c) something completely different.
    I’ll figure out the last Q but would appreciate some input regarding the seemingly high increase in ketone after only 5 days. Some general clues or tips on how to go from here would do. I’m fully aware that a proper diagnose and treatment plan, so to speak, is way beyond the possible.

    • Niklas, See if you can gather some objective data. For example, take “race pace” and hold that on a treadmill for 60 min (after a 60 min warmup) with VO2 and VCO2 apparatus to measure your RQ. This will tell you how you access your energy stores.

  • BobK

    Gotta love the generalized applicability of thermodynamics!

  • Reef

    Thank you for the great blog. I have learned a lot and started on quite a transformation. I am intermittent fasting 20 hours a day and refeading with a healthy very low carb diet. After 8 weeks I am down 25 pounds but my lipid panel has gotten terrible. Have cut out all sugar and processed foods now my MD wants to put me on meds for high triglycerides and wants me to stop the low carb lifestyle. What are your thoughts?

    • Impossible to say, but I bet your TG is especially impacted by the timing of the draw given your huge meal the night before.

    • Hemming

      Hi Peter,

      I recently had a standard lipid done after a little more than 20 hours of fasting which followed a pretty big meal. All numbers and ratios were good but I dad think about the timing and size of my last meal before the draw. I would have thought that 20 hours of fasting would be enough.
      How would you recommend eating/fasting prior to a standard lipid test to get the most reliable results?

      Thank you,

      • Whatever you believe is representative of your eating. Snapshot tests (e.g., fasting TG) are probably less helpful than AUC tests, but most non-snapshot testing is impractical. Lipids are not impacted much by recent meal. Glucose, insulin, TG are more sensitive.

  • CTRoberts

    I’m living the ketogenic life style, but I keep reading that high fat diets are highly correlated to prostate cancer! I’m in the 20% tile group and worry that if it’s true I’ll lose the battle trying to win the war. Ansel Keys was fooled his statistics… any thoughts?

  • Mary

    Hi Peter,

    Just a request for the subsequent parts of this series (if you still plan to do them). I would love to see you include the different possible culprits for people who have difficulty adapting to keto (despite plenty of time for the adaptation period, sodium, low enough protein).

    I recently cut carbs well below 50, adding in broth religiously and keeping protein low, and maintained that for 8 weeks with no cheating and still had exceedingly low energy levels. Is it possible that, for some people, the added metabolic cost of producing ketones is enough to make them feel tired indefinitely on this eating protocol?

    Also, we are hearing more and more about the dangers of low carb (thyroid function, stress on adrenals, lack of starches for beneficial gut bacteria, etc.). I would love to hear whether you think the evidence supporting these warnings is well founded.

    The reason I am so interested in a keto diet is that when I am not eating very low carb I tend to binge on carbs. For some reason I seem completely unable to eat “moderate carb”, as many are now recommending. I have been trying the moderate carb, “safe starch” approach for weeks now, but I always end up bingeing on very high carb stuff. Yet when I was eating keto for 8 weeks I never cheated at all and did not crave carbs (I stopped because my general energy was so low, and all the low-carb-will-blow-out-your adrenal warnings began to scare me.)

    • Probably worth a quick post on keto troubleshooting at some point.

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  • Bob K.

    This isn’t mentioned in your article (nor have I seen it mentioned elsewhere), but doesn’t the fact that someone in ketosis expels a bunch of energetic acetone indicate that ketosis wastes energy (ie, that you use more calories in ketosis)?

    • The amount and energy content of acetone in breath (and AcAc in urine) is between small and negligible.

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  • SB1790

    I can not believe I found other people in this world with similar viewpoints on nutrition. I have been in ketosis since 2001 after reading an article online about the Atkins diet. The journey into a ketogenic world started out as an experiment to see if a person could shave body fat without restricting calories enough to catabolize muscle (I had bodybuilder friends who wanted to get ripped and I thought Atkins might be worth trying so I tried it for them). So the Atkins experiment morphed into cutting out sugar and from there to no more than 20 gms of carbs a day if possible. That morphed into only organic foods. From then on it’s been fine tuning every so often such reading everything I could find concerning fats and oils (nutritiondata.com is great about going into in-depth detail about food composition) and experimenting to see what ratios worked best for me.

    I’ve never really came across anything (but I’ve not looked that closely) about people being on a ketogenic diet for decades or life. My blood work always comes back great but I’m approaching my mid 40’s now and I’m a little concerned about how this may have affected my body chemistry or certain gene expressions over a long period of time. I wonder things like: am I getting plaque in my arteries, are my telomeres shortening quicker than someone with a more even carb/protein/fat ratio? Stuff like that. Any thoughts about long term effects of ketogenic diet?

    I also personally believe that there is a difference in mood, concentration and how easy those are to control when relying on ketones for fuel. That’s only a personal opinion. Just found this blog today and found it interesting. I knew there were groups of people out there who ate very low amounts of carbohydrates but didn’t know there was anyone dissecting it in such detail. Great reads!

    Would also be very curious about any information on best fats (fatty acids) to eat in terms of their ratios (ie mono, poly, saturated). Not really in terms of those ratios for weight control but rather for optimal long term health.

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  • Bob

    Dr. Attia,

    I bought ketone urine test strips and my readings are 5 to 10 mg/dl. Does that correlate with my daily carb intake of 50 to 100 grams?


    • Urine strips are of little (no?) value, in my opinion.

  • Laura

    Thanks for this blog. Ketogenic eating has been a life changer for me and it’s good to get some more of the science behind it.
    I too would be interested in knowing more about long-term effects of keto, though my current understanding is that there aren’t all that many longevity studies on this… anything you know of would be helpful.
    Also, I have a friend who is very underweight and has struggled for her whole life to keep her weight up. She is interested in ketogenic diets because she has extreme blood sugar crashes regularly (she does not have any indications of allergies or diabetes). How would this way of eating affect a person like her? Would she have to do anything differently from those who lose or maintain weight on it?

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  • Hakim Hakim

    Phinney LE book on performance has a section where he discusses how exercise may actually NOT help speed metabolism or expenditure after exercise. He states that 4 well controlled ward studies evidence that and no good studies refute it. Just wanted to get ur take on that.

    • Correct, no reason to believe ketosis will boost anaerobic capacity. The question is how long does it take to adapt to the point where it’s not hurting anaerobic performance? In me, the answer was 18 months.

  • pone

    Peter, have you seen any data showing how many ketones can be produced from different types of fats: monounsaturated, polyunsaturated (omega3 and omega6), and saturated fat (including examples from each of the four fatty acid groups (e.g., lauric acid, stearic, etc)).

    I have started my first experiments with ketosis, and for whatever reason I had problems entering ketosis rapidly on monounsaturated fats. Mixing many fats over four hours got me there. Not sure if I have a timing issue, absorption problem (quite probable in my case), or if different fats do in fact stimulate different levels of ketone production.

    This topic is very relevant to what you focus on in this blog, and I think it would be worth of a separate blog post, assuming there is any literature of note to summarize.

    • Yes, but it probably varies by person and metabolic and hormonal milieu. Medium chain triglycerides of SFA, are generally most potent, with C8 (caprylic) being potentially the most ketogenic.

    • pone

      Peter, caprylic would basically be MCT Oil? I was using a large quantity of MCT Oil, but it makes me feel uneasy. It may be too thermogenic. As you say, there may be a lot of unique personal biology involved.

      If anyone else has studied this topic, it would be interesting to see this all quantified? In other words, for X gram ingested of different fats, how many ketones are produced at the peak level? It should be easy to approximate an answer to this by eating just one oil for four hours, starting from a ketone level of <= 0.2 mmol/L and then measure every hour until the peak is achieved.

      • MCT oil is to pants what caprylic is to jeans.

    • pone

      Started to do a research search on my question, and wow immediately finding very interesting data. Look at this study comparing ketones between saturated and polyunsatured diets:


      The polyunsaturated diet produced 2.7 TIMES as many ketones compared to saturated fat. Obviously most of us don’t want poly fats for other reasons, but this study is enough to make me think my intuition to study this question will produce fruit. I will report back after I have a summary of more studies.

  • Jason

    Hey Peter,

    Whatever happened to the rest of this series. I read every comment, and a lot of your responses refer to the upcoming parts of this series, but I can’t seem to find them anywhere.


    Hello Peter,
    Would you advise the American professional cycling team of Novo Nordisk (All cyclists with type 1 diabetes) to go ketogenic? Does the KD also reverse and improve on this type of diabetes?

    • Not necessarily. Definitely reduced GI and sugar intake, but this would actually be the perfect group for superstartch, just as it was developed for kids with GSD.
      T1D does not “resolve” with diet, but diet can reduced greatly the need for insulin and as such the morbidity of the disease.

  • Matt

    Hi Dr Attia,

    I use short term protein sparing modified fasts as a tool to reduce my “cutting” cycles on a strength athlete training protocol. It has worked really well with very little hunger. I have heard criticism to the effect that since carbohydrates are “needed” for gluconeogenesis that removing carbs is ultimately not optimal because some carbs are “needed” to efficiently convert fat into energy.

    While I don’t doubt the chemistry, my suspicion is that people are overestimating how many grabs of carbohydrates are needed to run the process and overestimating how effectively you can remove ALL carbs from your diet even if you wanted to.

    Could you please provide a rough estimate on how many grams of carbohydrates (or C6 H12 O6) are needed to burn a pound of fat? It would be a helpful number to help put things in context. My feeling is that even on a PSMF, the broccoli and spinach leaves I’m eating is low enough in carbs to keep my in/around ketosis but high enough to provide the raw material to run the complex reactions above (which in trusth can’t really follow).


    • Technically one does not need to ingest 1 g of CHO to mobilize and oxidize fat. Otherwise starvation would kill us.

  • david

    I’ve the ketogenic diet, but blood tests cost me Htrigtzridim and the LDL level is very high.
    I do CrossFit athlete loads and power, maybe I’m missing salts, magnesium, etc.

  • Martin

    Hi Dr. Attia,
    I watched your presentantion on IHMC – https://www.youtube.com/watch?v=NqwvcrA7oe8

    You describe there your experiences from metabolic chambers. I think you was there at the beginning of 2013. Can you write post about that?


  • Andrew S

    Thank you for writing a thoroughly informative article. I apologize if this question has been asked before, but I couldn’t find it with the search function, so I will ask… if I am eating ketogenic diet (about 65% of calories coming from fat, the rest from protein, and about 20g of trace carbs) and I overeat where I am in a calorie surplus (at least what would be considered a calorie surplus prior to starting a ketogenic diet), what happens to the excess fat/protein? As an example, if on a 40-30-30 diet with my normal weight lifting workouts and daily activity my caloric maintenance is 2800 calories and on the ketogenic diet I eat 3800 calories, can I still gain fat since insulin is almost nil? I read so many conflicting theories that I don’t know what to think. Some say that you can absolutely gain fat in ketosis if eating a caloric surplus… others say there can be no caloric surplus in ketosis due to entropy and that bmr increases in ketogenic dieters to match the caloric intake, thereby making a calorie surplus impossible….still others say that excess calories are excreted. What is your take on this?
    Thank you. Can’t wait to hear your answer!

  • Andrew S

    I read the fat flux post today. I saw that you mentioned that the state of ketosis itself provides a metabolic “disadvantage” due to the process of making ketones out of fatty acid (both stored through lipolysis and dietary). I also noted that you were able to eat nearly 4500 calories on a ketogenic diet and lose fat whereas on a moderate/high carb diet you were eating quite a bit less calories just to maintain weight. I do have an additional question: what do you think would happen if you ate 15,000 calories per day on a ketogenic diet instead of the 4500. Assume that you could force-feed yourself every day with that exorbitant amount of food. I mean, at some point would a caloric surplus be created whereby your body would store the surplus as fat or do you think that theory by your friend Kevin would hold up and your body would match the exorbitant calories in by using all that extra energy (calories) to make ketones out of fatty acids?

    Also, what is your take on a carb cycling diet where you eat keto for 5 1/2 days and high carbs for 1 1/2 days?

    Thanks again.

    • Andrew


    • Andrew S

      Hi Peter, I would really appreciate if you can answer my follow up question. Thank you.

  • Mike

    Many thanks to you for sharing this info. It has been revolutionary to say the least. What really got my attention was that your weight retention story is very similar to mine. After 7 years of triathlon training etc. and limited weightloss I needed a different approach. I have a picture of myself right after an Olympic distance tri and 8 months of training and so called “good eating”. I still had a gut. Not fair. I’ve been in NK for over 3 months and lost weight and inches. This is the easiest eating plan I have ever experienced and i’m moths ahead of my usual weight loss. The ability to cycle for hours without breakfast and not cramp; the ability to go most of the day without being ravenously hungry, is a dream come true. This works for me and my cholestrol panels are better than ever. I plan to do IM New Orleans next spring on this NK plan.

    I do have a question about proein intake and gluconeogenisis: I understand that my protein intake needs to be less than 140 grams daily or I risk producing glucose through the process of gluconeogenesis. I also have read many times that the body can only process approximately 30 grams of protein at a time. If this is the case and I eat two meals a day, each containing 70 grams of protein, am I then converting the extra 40 protein grams each meal back to glucose. If so, shouldn’t it make more sense to stretch out my protein allowance into additional meals throughout the day to ensure it gets uploaded for it’s beneficial use as protein and not an undesireable conversion.?

    I keep reading from most of the NK authorities, that you guys are only eating twice a day on average. Hoping you can clarify this for me Thanks again.

    • I’m not sure about the 30 g “rule.” Seems such a think is highly context and individual specific.

  • newbie

    Re – “B-OHB enters the mitochondria, converts into acetoacetate, and enters the Krebs Cycle directly (between succinyl CoA and succinate, for any biochem wonks out there). I keep alluding to this distinction for a reason that will become clear shortly.”

    It doesn’t appear to me that B-OHB “enters” Krebs between succCoA and succ – it just accepts the CoA (and SuccCoA moves along the TCA cycle to become succinate) so that B-OHB can eventually become acetylCoA and enter through the same door as the as all FFAs which have undergone beta-oxidaton to acetylCoA . I am clarifying this in order to ask a question – what is the point of ketones (besides the brain), since the peripheral tissues have plenty of access to NEFAs, and both FFAs and ketones enter Krebs as acetylCoA? In other words, how to ketones enhance cellular metabolism if they are just increasing the “traffic congestion” at acetylCoA? Ketones don’t have a separate metabolic pathway.
    I know this is years after you posted this, but maybe you’ll see this biochem question and decide to answer it?

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  • George

    I didn’t know where to post my question. I guess this is as good as anywhere. I was just watching Dr. Dominic D’Agostino on a TED presentation. He repeated a statement I believe you have made and I keep hearing repeated over and over. Basically it goes something like, “When drugs fail, it has been shown that a ketogenic diet can help control seizures in children with epilepsy”, and sometimes there are other types of seizures mentioned. My question is why wait until after drugs fail? Wouldn’t it make more sense to use the ketogenic diet first and then use drugs as a last resort instead of the other way around?

    • It’s actually a good question, you ask, George. The answer is multi-faceted, but it probably stems from 2 things: 1) the culture of medicine (drugs first), and 2) the fear of KD (e.g., heart disease)

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  • newbie

    Hi again Peter,

    My question was put forth with complete sincerity and with due respect. I acquired an excellent knowledge base about cholesterol from reading your original series of articles, and I’m hoping you can clarify something else for me.
    I am having difficulty reconciling your explanation of ketones’ unique pathway with Chris Masterjohn’s piece on ketosis (http://blog.cholesterol-and-health.com/2012/01/we-really-can-make-glucose-from-fatty.html), specifically the section…
    “When large quantities of fatty acids flood the liver during fasting, caloric restriction, diabetes, or the consumption of a low-carbohydrate, high-fat, ketogenic diet, our livers produce so much acetate that the TCA cycle suffers heavy traffic. Any acetyl CoA with the foresight to listen to the evening traffic report would quickly decide to head straight for the Land of Ketogenesis, where the railways are open and the paths are free. This is where our livers turn acetate into ketones, sending the ketones out into the bloodstream so our other tissues can use them for energy.”

    If ketone bodies (made in the liver and sent out into the periphery) need to be converted back to acetylCoA to enter the Krebs cycle, how would that be of any help to the peripheral cells that are already overflowing with acetylCoA (from FFA beta oxidation)? I really would appreciate if you help me to understand where my thought process is incorrect. I do know you’re busy, I am hoping that the answer is short and simple. Thanks for your time.

    • BHB converts to AcAc and generates succinate via Succinyl-CoA Tranferase (SCOT). The liver (where ketones are made) lacks SCOT, and thus spares ketones for other tissues.
      Most cancer cells lack SCOT, also.
      Remember, ketone oxidation is an another pathway (regulated tightly by insulin) that parallels beta oxidation of fatty acids.
      The main purpose, however, is to ensure high energy flow to the CNS when glucose is limited. Bigger brained animals have higher capacity to use ketones it seems.

  • newbie

    Thanks for a clear and concise answer – so the utility of the ketones is the brain, not the peripheral tissues, and hence your excellent talk on ketosis and the prevention of “bonking” vis-a-vis athletic performance.

    • No, peripheral tissue can use ketones (and seems to prefer it) also, as does the heart. The point is why we do it. That’s where the brain come ins, from an evolutionary perspective.

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  • Inflammable

    With the availability of breath ketone meters I’m wondering how many kcals a keto adapted person loses through respiration. The vapor pressure of acetone is quite high, ~400mmHg at body temperature. The loss of ketones could explain the slightly lower RQ of keto adapted athletes than predicted by a simple minimization of the Gibbs Free Energy calculation.

    • It’s been measured and it turns out to be quite low in energy, given that acetone is not the dominant energy currency ketone body (AcAc and BHB are).

  • Gale Hawkins

    Thank you Peter for all of your work and making it public. I have read Part I and II of Ketosis-Advantaged or misunderstood posts. As a WM63 who has lived with AS (Ankylosing Spondylitis) most of my life I was asked to read up on Embrel and consider doing the weekly injections. I was very interested in Embrel until the repeated word cancer kept popping up but on the bright side I learned about coconut oil for the first time and have a light bulb go off.

    I have been on organic virgin coconut oil for two months and use the $15 breath analyser of of eBay that uses three AAA batteries. Even after I got up to taking 8-12 table spoons 3-4 times a day nothing much happened. Readings like .005 to .02 %BAC was the best I could do for the first month. After two months I did hit .086 this morning.

    Now I am wondering if my liver was at first not doing a good job at burning fat or does it just take time to adapt? When I came in this evening I blew .008 and now four hours after taking 2 table spoons of VCO the meter just read .021 %BAC. I gather this cheap meter is actually measuring breath acetone level. By the way I have been doing a better job of staying away from carbs and food with added sugar. The pain level has decreased some too. For the past 10 years I have only been taking fish oil because the NSAIDS had did a number on my stomach, balance and mental clarity.

    Thanks again. Gale Hawkins

    • Gale Hawkins

      I should have said a TOTAL of 8-12 table spoons a day in 3-4 dosages. 🙂

  • Mike

    I have recently been diagnosed with type 2 diabetes. I made the choice to cut out sugar and carbs from my diet independantly from any advice. After being told by many people that it was a dangerous thing to do and I could go into seizure and die, i searched around the internet and found this site. In the one month that I have stopped taking on board carbs I have lost nearly a stone. I dont seem to be having any ill affects and have been kind of waiting for them to kick in. I am overweight so figure that my body is now using my fat reserves to live. My question is as follows. I was prescribed Metaformin 500, should I still take this if my carb intake is just about zero? I have started being able to fast for up to 24 hours without any intake of food except for tea and coffee with milk and perhaps a couple of apples during the day. Is this causing me any harm? Any guidance would be appreciated

    • Mike, you’ll need to get that advice from your doctor, but I am a big fan of metformin use in my patients.

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  • Idan

    Hi Peter,

    I will spare my story of T1D diagnosis 3 months ago, and having to confront the ‘system’ while putting myself on KD before even knowing what it is.

    I would like to thank you for providing all this invaluable crunched information that is nowhere else to be easily found. The time and effort you put into this blog is having a huge impact on my personal dietary choices.

    I have one question that I hope you will be willing to answer –
    I have been (and still am) repeatedly told by most ‘professionals’ (MDs, dietitians, trainers etc) how KD is dangerous for me, yet not one of them can offer me a convincing evidence (or even a theory for that account) as to why so.
    What are your biggest concerns about your dietary journey in the long run? And by concerns I mean hypotheses that have yet to be proven right or wrong by appropriate studies.

    Thanks again

    • Idan, T1D, as you know, is a pretty unique state and I share the concern of your doctors. While I probably have a different view from them on the ideal diet for T1D, I would agree that a diet producing ketones could be tricky to manage given the lack of endogenous insulin to feedback on the system.

    • Idan

      Thanks for the reply,

      I assume (and please correct me if the assumption is wrong) that you’re referring to the danger of not being able to monitor for dka based on ketones (which is still manageable with constant BG monitoring). I was curious to know though if you had any concerns at all for long term effects regardless of T1D

      • The danger in T1D is that the feedback loop–high ketones stimulating insulin to in turn reduce ketones–doesn’t work, which is how someone with T1D can have BHB levels over 15 mM and resulting DKA.

  • Teresa

    I’ve been vegan since March 2014, it’s December 2014. Previously, I was a half-assed, wanna be, lacto-ovo-vegetarian most of my life. I’ve very intentionally dropped 35+ pounds and am just 5 pounds away from my “ideal” weight for my height and age: 57, 5’8″ female. I currently weigh 144. God it feels so good to FINALLY be here!!

    I was wondering about my very definite state of euphoria and significantly increased energy. A girlfriend suggested ketosis. Naturally, my reaction was “YUK, NO WAY! Can’t be!” Last time I was in Ketosis was in my late teen years trying to lose weight on the horrible (IMHO) Atkin’s diet.

    I try to go raw as much as possible, but occasionally have some processed foods, like Tofurkey Pot Pies, for example. The more I stick to raw, no question, the better I feel. I KNOW when I feel this way (great euphoria and tons of energy) that the scale will be kind to me in the morning (stays even or tenths of a pound drop). The less I eat, the better I feel. I now LIKE that kind of empty feeling in my gut area. Having a full belly is no longer a good feeling. Usually means I just ate too much food. I pay a lot of attention to what I’m eating and drinking. But, for sure I get PLENTY of carbohydrates. I have to get the test strips again, but from reading above, I’m not sure they’ll be an accurate indicator of actually being in Ketosis. I swim every day and will be starting a weight work out very soon.

    I wondering if I’m in Ketosis and I was thinking from my past 40-year-old or so information if it’s a bad thing. Still hard for me to tell from the article. I guess I also wanted to weigh in with my experience of it (if that’s what it is) as a vegan and feeling great. Super great. Thank you!

    • Congrats, Teresa. No, I think it would be hard to imagine a scenario where you are in nutritional ketosis.

  • Jason

    Hi Peter,
    I stumbled on one of your You Tube presentation a few months back and became an instant fan, what you said resonated with me. i don’t have any medical issues, but at sixty I figured that I better start paying more attention to my health. Anyway, long story short, I started my low carb high fat diet on Oct 27th of this year. i wish I can call it a Ketogenic diet, but it’s not been easy getting below 80g of net carbs with about 80 in protein and about 170 in fat… I won’t bore you with all the details, since my questions isn’t really about me but i figured a bit of background wouldn’t hurt. I also feel great, even though the rest of my family think i lost it and sure to explode any day now.
    In my wanderings on the internet, I kept seeing references the the Gerson Therapy. Seeing that it was more for cancer and degenerative disease therapy, I didn’t pay much attention until recently. Can you shed some light on their logic? While they do agree that sugar (white processed that is) and grains are bad, it seems like they are all for vegan, juicing, nearly raw foodist and against dairy, fat (animal or plant), salt, etc…
    I appreciate your comments. please keep up the good work.

    • Jason, no need to “wish” for ketosis…it’s not necessary for health/performance. It’s simply another manifestation of using diet to reduce insulin and trigger a different metabolic pathway. That said, the bigger point/question is complex one. I can’t speak for their logic, though it should be noted that if the dietary triggers of metabolic disease are sugars and highly refined grains (i.e., the foods we did not consume at all or in excess during our evolution)–and I do subscribe to this hypothesis–then two vastly different dietary strategies that remove the same triggers can both produce similar results in terms of disease prevention. That’s the short answer. The long answer I don’t have time for, but it gets into the nuance of individual variation and susceptibility. Maybe something for a podcast one day. I think Tim Ferriss is collecting comments/questions for our Part II podcast in January.

  • Kevin

    Peter, are you still practicing medicine as a surgeon? I saw your TED MED presentation but then saw reference to your patients above. Just curious; I apologize if this is too personal.

    Thanks for time and passion with this blog,

    • Not too personal. I left surgery in 2006. I do practice (non-surgical) medicine now, but only ~10 to 20% of my time. Most of my time is spent on NuSI.

  • Jason


    I’ve tried to read through most of your information, but I apologize if I missed the answer to my question. I started a low carb diet seven days ago — eating somewhere between 10 and 20 net carbs per day — and so far it’s been fairly easy. However, last night I could not fall asleep and had what seemed like heart palpitations or at least an irregularly strong heartbeat. I’ve read several other websites that claim low carb diets can cause insomnia and hypoglycemia, yet I get the sense from reading your material that you disagree. Do you believe my difficulty sleeping / strong heartbeat will pass if I continue with 10 – 20 net carbs per day, or should I increase my carb intake to manage my heart irregularities? My heart has been beating harder today as well. Normally, my resting heart rate is around 45, but today it is at 70. I am a very active 33 year old guy in the Army who works out regularly. Thanks in advance for your help!


    • Maarten vT

      Hi Jason,
      How did it develop for you? I have more or less same situation: started low/no-carb ~7 days ago. Felt great, but also felt resting heart rate increasing (in my case 60 -> 70-75), very noticable at night but also during the day. Also found my blood pressure was lower… Basic stats: male, 43y, 6ft2, 82 kgs, body fat ~10%.
      Any thoughts?
      Kind regards,

  • Shelli Johnson

    Hi there. Thank you for all of your sharing and informative and inspiring content.
    I’m writing because I’ve been following a Ketogenic diet for 134 days (trace ketones for 134 days in a row, per my Ketonix Sport) – and I have GAINED 13 pounds in the last 6 months.
    Excuse my language, but WTF??!!!
    I have never felt more energetic, alert or mentally better. However, I don’t wish to be packing on more weight and fat… Feeling great is not enough for me. I’m an adventure guide and I’m hired by corporations as a motivational speaker. How I look matters in how I show up and how effectively I can do my work and be myself. The inexplicable weight gain, especially when I’m doing lots of fasting and following a ketogenic diet makes no sense to me…
    A little backstory… I’m a leadership and wellness coach, and very much a self experimenter. I am 46, a mother, wife and entrepreneur. I am an Epic Adventurer and a very fit athlete. (I hike 1,000 miles a year)
    I don’t eat any grains… In May 2009, I gave up all grains. The results were staggering: I lost 30 pounds and 15% body fat in a single year after those changes. I burned the boats on the grains back then and have never looked back.
    Today, almost 6 years later, I’m 46. Until the last 6 months or so things were still going great and I had kept all the weight off. However, today, I am up 10-14 pounds (in the last 6 months.)
    This is crazy! How can this even be possible? Is there something wrong internally? I had some labs done via WellnessFx last May, and thyroid and other markers were normal… Nothing stood out…

    I would GREATLY APPRECIATE a response and a direction for where to turn for a consult. I am so excited about how the Ketogenic diet makes me feel, but I am not happy to be gaining so much weight and it doesn’t compute. I am at wit’s end and really needing some help here?
    Shelli Johnson

  • Michelle

    What fantastic information you have here. I have stumbled on the site as I look for information on my teenage son’s acetone breath. He is a wrestler, at a weight I feel is too low and have been wondering if he is going into a state of Ketosis days before weigh-ins. If I smell strong odors of acetone on his breath (along with him barely eating or drinking) – is this alone enough to indicate the ketosis? He is very thin; it is hard for me to imagine where his stores of fat are hiding. I have been reading along looking for the clues about how dangerous this can be; the only danger I seem to be digging up here is the danger from ketosis related to diabetes. This is unrelated to diabetes. Is there danger from being in a state of ketosis when you do not appear to have any fat stores in reserve? What are the ramifications of him doing this? Thanks for any info

  • marcus jones

    Thank you Dr. Atia. I just wanted to share something and see if what’s happening to me might be happening to others. I pretty much started keto (Atkins) without doing any research. It wasn’t long before I did as I began to feel a tad “strange”. I noticed one day, as I was sitting in my truck, that I felt CALM. As if I had no more fear. It almost seems as if my body is not fighting with itself anymore. Has anyone else ever experienced this?

    • Maarten vT

      Only started one week ago… So very early, but experience some kind of ‘basic calm-ness as well. I’d say it’s a good thing.

  • Ernst

    I read Gary Taubes “Good Calories, Bad Calories”. It was a brilliant read.
    I wasn’t even trying to lose weight. But out of curiosity I started eating a high fat / low carb diet.
    In a short while, my weight dropped from an already meager 68kg to 64.5kg.
    (I don’t know if I was ever in Ketosis, I don’t think so.)

    So, I’m personally convinced beyond a doubt that low carb makes you lose weight.
    I was just wondering. I’ve not found a single study , proving beyond a doubt that on the long run
    eating a high fat diet does not cause Liver-problems(like gall stones) or Atherosclerosis.

    Should I worry about the long term effects of eating a high fat diet? And, since you’re basically
    a living experiment of one, do you worry about the long term (say 20 years) effect of living in Ketosis?

    • Ernest, I don’t know what 20 years of consistently being in ketosis does and I’m not sure anyone does. I was in ketosis for a little over 2.5 years and couldn’t measure any downsides, though there may have been some. The question should be, however, a relative one. So it’s not is Dietary Pattern X “good” or “bad,” but is better than A or B for a given individual? In that context, 20 years of ketosis would have been better than 20 years of what I did before.

    • Maarten vT

      Question: effect of low-carb (or NK) on resting heart rate & blood pressure
      Hi – I also came across the work of Mr. Taubes and started, more or less cold turkey, to cut out carbs to see what happens.
      Base: male, 43y, 6ft2, 82kgs, body fat (estimate) around 10%.
      Previously I had already cut out ‘sugar’ (added glucose) from my diet, but I did still eat a lot of carbs (bread, muesli, potatoes).
      I’m now in for a week, still early stages. I feel great! No more the ‘hunger attacks’ that I used to have (and the ‘deal with’ eating carbs). I’m sligthly concerned about my resting HR – used to be around 60 and now seams to have climbed to 70-75. Also, my blood pressure has dropped (as I found out after donating blood). Was wondering if changes in resting heart rate & blood pressure could be attributed to eating a low/no-carb diet?

  • Aladin

    Ernst — the two prime factors in gall stone formation is genetics and diet. The former being hard wired as it were.. the latter a complex combination of overall diet choices and exercise level/sedentary lifestyle. HIGH insulin levels program the body into fat storage mode and start this cascade of stone formation which is genetically based. I’ve never read anything per diabetics staying on a low carb & higher fat content diet as being predisposed to stones per those diet choices. IMO.. gall stone formation is likely an epigenetic trait.. IE: sedentary lifestyle with long term high insulin levels trigger a genetic expression to form stones.

    Your weight loss on the high fat diet could mean your body is loosing muscle mass… using them as a source of protein… likely to a minor extent. Your system has adapted to your current ‘fueling’ level and adjusted the total weight downward… being now a little leaner. WISH.. I had your genes… !!

    Observe the people exiting any large grocery store.. I say large because one then gets the message quickly. So many of them actually WADDLE carrying those excess pounds. Go into the store then and observe their food choices.. carts loaded with processed foods loaded with wheat and various forms of sugar. This is the face of the looming health crisis coming in the country.. as this population ages the cost to our society will be enormous.

    Genetics.. a complex code with everyone’s being different. Your weight will vary as mine does per diet choices. Finding the balance that works best for your system isn’t dependent on what the scale reads.. rather how you feel per energy levels & mental functioning. Your body adjusts to your current feeding level… with no history of family gallstones there’s IMO no reason to be concerned with stone formation on a reduced carb diet.


    • Aladin

      NOTE: addition to this post.. last burb per my opinion and NOT med pro.

      Aladin February 21, 2015
      Your comment is awaiting moderation.
      Ernst — the two prime factors in gall stone formation is genetics and diet. The former being hard wired as it were.. the latter a complex combination of overall diet choices and exercise level/sedentary lifestyle. HIGH insulin levels program the body into fat storage mode and start this cascade of stone formation which is genetically based. I’ve never read anything per diabetics staying on a low carb & higher fat content diet as being predisposed to stones per those diet choices. IMO.. gall stone formation is likely an epigenetic trait.. IE: sedentary lifestyle with long term high insulin levels trigger a genetic expression to form stones.

      Your weight loss on the high fat diet could mean your body is loosing muscle mass… using them as a source of protein… likely to a minor extent. Your system has adapted to your current ‘fueling’ level and adjusted the total weight downward… being now a little leaner. WISH.. I had your genes… !!

      Observe the people exiting any large grocery store.. I say large because one then gets the message quickly. So many of them actually WADDLE carrying those excess pounds. Go into the store then and observe their food choices.. carts loaded with processed foods loaded with wheat and various forms of sugar. This is the face of the looming health crisis coming in the country.. as this population ages the cost to our society will be enormous.

      Genetics.. a complex code with everyone’s being different. Your weight will vary as mine does per diet choices. Finding the balance that works best for your system isn’t dependent on what the scale reads.. rather how you feel per energy levels & mental functioning. Your body adjusts to your current feeding level… with no history of family gallstones there’s IMO no reason to be concerned with stone formation on a reduced carb diet.

      Understand I am NOT a medical professional and am expressing my opinion per my experiences over time. I come from a family with many very obese individuals.. none of which formed gallstones. Apparently our genetics aren’t predisposed to gall stone formation.


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  • Rogelio


    Thank you for this information. It must of taken you a very long and dedicated period to collect the panoply of research here. I am greatful for USEFUL information like this especially in the light of all the anactodtal responses to this question. I am relativley new to this topic and as a young medical student am only interested the more. What advice can you give for someone like me ( a novice) who has the relative scientific background to persue this question more in depth ( by that I mean with the science to back up the claims) what literature, if any can I read? Also 2) how does one get started in NK? are there useful dietery cookbooks– perferably general guidlines– that one can use?

    Thank you very much for this information again!

  • Andre

    **************(skip if in a hurry)**************
    I have already watched all your videos I could find and am currently working on reading through your whole blog. I could write pages about how great ketosis, your blog, your talks (and butter) are and how helpful they were for a wide array of questions I had so far, but I’ll have to skip that for brevity. I am currently experiencing a multitude of benefits from a very low carb diet and have successfully introduced several family members to this lifestyle. I would describe the feeling of having ketones for energy instead of glucose as “honey-peanut-butter flowing through the brain” and am sure many can relate.

    I would like to allow myself to ask for your opinion and maybe challenge you a bit (as you requested on your startpage) on two things, for which I could not find good answers yet:

    1. While looking for some Magnesium in a drugstore, I saw a supplement that is supposed to block the absorbtion of carbohydrates in the gut. Now, for people like you, who got their ketogenic diet figured out, this probably would not make a huge difference and of course I am not proposing that people use such a supplement to eat huge amounts of carbs and then artificially block them to be in ketosis (that would just be stupid) but this be of help for some people? Are they reasonable for people really struggling hard with their insulin resistance?
    Could they enable a wider range of people, especially morbidly obese people, who do not have necessary resources, to benefit from a ketogenic diet by increasing the carb threshold for ketosis?
    I would be interested to get your opinion on the idea of blocking excess carbs from affecting insulin.

    2. As I am most interested in the effects ketosis has on the brain, I read about some people experiencing a decreased need for sleep on a ketogenic diet. Assuming these experiences are related to ketosis, could you think of an explanation for this phenomenon?
    Could it be because of the decreased production of reactive oxygen species?
    Could it be because of the more efficient brain activity caused by ketosis which needs less rest at night?

    I would like to thank you in advance for answering comments in such an engaging way (which is astonishing considering the number of comments here) and wish low insulin levels to all!!

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  • Bruce Reid

    Seeking recommendations for the best diet software.

    I have only recently begun to explore and experience a ketogenic nutritional approach. While seeking to learn more about the subject, I discovered the wonderful EatingAcademy website. I enjoy preparing my own food, and have adequate time to devote to it. So far, I have relied mostly on intuition to design meals that are healthy, and place me in a state of ketosis. I have been fairly successful to that extent.

    The thing I’m having a more difficult time with, because it requires a bit more than intuition, is how to monitor my caloric intake so that I can safely and reliably lose some of my excess fat, but make sure I’m not losing lean mass. I feel like my motivation to eat has definitely diminished, which would lead me to think I’m consuming enough calories, but I’m not sure.

    I have briefly searched for diet software to help me monitor my nutritional intake, and have found a few choices. But I’m not yet sure which of them might be best. I would like an application that meets the following needs:

    Multi-platform (Windows, Mac OS X, primarily)
    Easily input of complicated recipe ingredients, with ingredients / serving sizes in metric or English units
    Access to large and reliable food database
    Not too expensive

    Thanks in advance for any recommendations!

  • Bruce Reid

    Methods to test for presence of ketones.

    I embarked on the low-carb lifestyle very recently, and using KetoStix, have found that on each test, I seem to be in a state of ketosis to some degree. I’m wondering if someone might suggest a device/method to more precisely detect ketone levels, and where such a device can best be obtained.


  • Bradley


    As you outlined in your IHMC talk there are multiple pathways the body can mobilize glycogen for ATP in muscle tissue dependent on the time/power dependent demand. Are there also multiple pathways for metabolizing adipose tissue for ATP other than by the lipolysis you outlined for ketosis. Also what is the pathway/cycle in which fat is mobilized for fuel when someone is not in a ketogenic state?

    Hoping this finds you,


  • Luba

    I’ve been on fruit only protocol for seven days now, been checking urine daily with a test strips.High ketones level every day, lost 8 lb in one week. I eat apples, pears, grapes, berries, melons,no citrus or bananas. Plenty glucose and ketosis without additional protein.


  • uraz oflaz

    “BHB converts to AcAc and generates succinate via Succinyl-CoA Tranferase (SCOT). The liver (where ketones are made) lacks SCOT, and thus spares ketones for other tissues.
    Most cancer cells lack SCOT, also.”
    I dont fully understand what you mean by this, doesnt AcAc generate succinate as it converts to AcAc-coa, which gets further metabolized into 2 molecules of Acetyl-coa by the addition of another coa ? Since succinate eventually gets metabolized into coa as well wouldnt BHB yield more acetyl-coa than glucose through its own metabolization. So why was the increase in acetyl-coa necessarily attributed to increase PDH activity? It simply could have been the result of direct BHB utilization. Wouldnt measuring the rate of glucose depletion in the medium be a better way of seeing if BHB activates PDH ?

  • Catherine

    Hello there! I am a post menopausal women and have fought my menopausal weight gain for years–trying every diet/lifestyle change out there BUT nutritional ketosis/ketogenic diet–this is actually my last hope. Is this lifestyle change effective for a woman in my phase of the meno life? Also what is a good starting point for a book/website information on a step by step guide to get started. Thank you!!!

  • pascal

    Hi Peter. I saw someone else has already asked but couldn’t see a reply. What are your thoughts on a cyclical ketogenic diet? Going by what I’ve read, I can’t see the need for a 36 hour carb load over the weekend. Would the carb loading only be benificial for muscle hypertrophy as opposed to reducing body fat and getting lean? Great article BTW

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  • Dougie

    I’m struggling a lot with this article.

    why is it important to recall the acute effects of insulin? None of them seem to lead to the “complex cascade of events”, they all seem like benefits to me.

    GIK (glucose + insulin + ketones) resulted in the greatest increase of cardiac efficiency, so why is this not seen as the preferred state (for performance, at least)?

    in the table showing the delta G values, GIK (glucose + insulin+ ketones) and GI (glucose + insulin) had the lowest values (or highest negative values, if you will) – doesn’t that mean there was greater energy released, in comparison to GK (glucose + ketones)?

    why is more insulin forcing more pyruvate towards PDH into acetyl coA a bad thing? Isn’t good to have more acetyl coA??

    how does the anaerobic system not leverage the delta G improvement? Thus, why would nutritional ketosis not be advantageous for anaerobic power and/or muscular strength?

    I don’t understand the hall paradox – if ketones (B-OHB) can produce more energy for less oxygen, are they still a more efficient way of producing energy for athletes if there’s a large energetic cost involved in making ketones from fat? why/why not?

    I feel the finding from Henry Lardy on the efficiency of B-OHB contradicts the finding from the table 1 of that study shows a lower delta g value for GI (not ketones!).

    why do you talk about B-OHB in moles when the study you showed talked about them in millimoles? I found this made it difficult to compare the enthalpy of B-OHB and stearic acid to the delta G values of the study (I know enthalpy and delta G are different things, but I don’t see how else I can appreciate energy cost of converting fat to ketones).
    Also, how do you conclude that there is thus about 20% energy lost in that process?

    Thankyou so much for this post, it was pretty freaking awesome, even if it confused me. I am extremely grateful for the time and effort you put into your posts and this one has done wonders for how much I idolise you.

  • John Redmon

    Dr. Attia – I was wondering if you could help me with a keto biochem question? I’ve always loved your blog and I’m in NK (1.2 mmol/L this morning). I will add that I had four science majors in college (but that was a long time ago) and I used to be a professional triathlete (that was a long time ago, too).

    Some have touted MCTs as being converted to ketones. In fact, Dr. Mercola wrote an article along these lines this week (3/6/2016), saying:

    “MCTs are fats that are not processed by your body in the same manner as long-chain triglycerides. Normally, a fat taken into your body must be mixed with bile released from your gallbladder before it can be broken down in your digestive system. But, medium-chain triglycerides go directly to your liver, which naturally converts the oil into ketones (unless you are on a statin drug, which blocks the liver from converting them to ketones), bypassing the bile entirely.

    “Your liver then immediately releases the ketones, which are water soluble, into your bloodstream where they are transported to your brain to be readily used as fuel. Additionally they do not require L-carnitine to shuttle them into the mitochondria for fuel.”

    That doesn’t make sense with my science understanding. My understanding is that such a system DEPENDS upon whether one is, or is not, in a ketogenic (or starvation) state. The idea that if one eats MCTs, converting them to ketones depends upon the ketogenic (or starvation) state.

    My understanding is that triglycerides are broken down to FFAs and taken into mitochondria and turned into Acetyl-CoA and subsequently put through the Krebs Cycle and ETC to make NADH, FADH2, ATP, etc.

    In non-ketogenic people (glucose burners), the Krebs Cycle continues its steps to make ATP, etc. But, ONLY in ketosis (or starvation) will oxaloacetate be depleted in the Krebs Cycle, and, then, the metabolism switches to GNG AND the production of ketones. Thus, my understanding is that ONLY when you’re in ketosis will liver mitochondria produce ketones; not by simply ingesting MCTs in a non-ketogenic state.

    I also understood that ketone production doesn’t depend upon FFAs ability to enter mitochondria (i.e., whether they need the carnitine shuttle or not, or whether they need albumen as a carrier molecule to be water soluble in the blood). It’s whether oxaloacetate senses the depletion of pyruvate (from glycolysis) that initiates GNG and ketone production (again, not simply drinking MCTs).

    Am I missing something? Or can a non-ketogenic person simply consume some MCTs and they’ll be converted to ketones?!


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  • Ivan N.

    Peter, you know your shit man! Thanks a bunch for explaining all this.

  • Catherine

    Broken links above – please provide the accurate links. I would like to read this information in looking for clinical basis for Keto. thanks

    “A broader question, which overlays this one, is whether any change in macronutrients impacts TEE. If you’re interested in the entire review of the literature on this topic, refer to this appendix (LINK BROKEN) from the exhaustive review we did at NuSI, along with this summary(LINK BROKEN) and narrative(LINK BROKEN). This review spans over 80 years of research and 1.2 million subject-days. ”

    GREAT WORK – thank you!

  • John Anderson

    Seven weeks into ketosis, no problems at all during adaption through a variety of sports/fitness activities. Any evidence out there to support the armchair theory that this might be due to the fact that I started (& never went excessively long periods without intense) weight training at 14 yrs of age (some 31 yrs ago), and perhaps developed “improved” insulin sensitivity?

  • Andy

    Great post. Is it possible to specify exactly where the lesser requirement for oxygen is? If fatty acid oxidation, the link reaction and the Kreb’s cycle are all anaerobic then does that indicate the oxygen savings are at the electron transport chain? Or am I completely off track?

  • Jeannette Tetz

    I have been *flirting* with NK for some months now. I like the science and I find the eating style fairly simple to follow. I am a RNY Gastric Bypass patient from 2000, when I had surgery I was around 550 lbs, now I am in the 250 range. I am working on this next 50 or so pounds and try to stick to a strict <30 carbs per day budget. I have not found any discussion around RNY patients and NK here and am wondering if you have any ideas around this population. NK has the potential for much greater calorie intake at much smaller volume. Since my volume is quite restricted, and absorption is kind of an unknown at this point… Do I modify anything? I find I cannot turn a pee stick much past "trace" for love or money, but I need to avoid going full eating disorder and getting my calories so low I just fall over dead – or kill someone … I am going to get a blood test kit, but what if I discover I just cannot get in to NK! I just wonder if there are details around my altered anatomy which I should pay attention to? My husband and son lost all their chub in under 6 moths on Keto (both with a fairly "normal" metabolic reality). I loose the initial water weight, but from there NOTHING. Even when I add exercise.

    There is only so far calorie restriction goes – what might I be missing?

  • Htaylorrd

    I am also interested in women’s hormone influence of low insulin. I also noticed a concern with some people who see elevated liver enzymes. I would believe this would only happen when you are NOT keto adapted. This was observed in the mouse studies where exogenous ketones were given to mice with a mixed diet….which would be similar to the average population. I’d love more studies on the use of exogenous ketones with zero diet changes and not being keto adapted on liver metabolism. Any studies on exogenous ketones in the sedentary SAD diet population?

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  • Jason Rochon

    So my question is… if a population of people born with congenital heart defects need to focus on longevity, would diet (in this case ketosis) be the direct answer to the end game surgery or catastrophic event. Also I think you have shown in several of your posts that overall obesity trumps anything else, so would (or would not) the goal be to eliminate the obesity and worry about stressors on the heart after you have attained a better ground to stand on. I have heard two opinions from doctors or friends that go as such.

    Doctor # 1: Light cardio, standard american diet, high in fibre and low in cholesterol, the more you relax the less stress is placed on the cardiovascular system.

    Doctor #2: Interval cardio, LCHF diet, heightened cholesterol markers, focus hard on burning the adipose fat off to attain a better fitness level.

    Side note: Is there any data that you have seen for success rate of cardiac surgery for obese patients vs. normal or lean patients.

    This of course is anecdotal or hypothetical question, seems to be little shown for how best someone to manage a congenital disease vs. one of getting older. My question also doesn’t take into full effect the benefits of Ketosis and nearly asks from a predisposed cardiac example.

    And I love your blog its great reading for someone who never had the chance to go to medical school, etc. Please keep doing what your doing!


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  • Roger Oesterling

    Do you have any evidence that suggests that cycling in and out of ketosis is beneficial? What are the number of days in ketosis and number of days out of ketosis for the conditions (high athletic, moderate exercise, etc…). What were the carbohydrate and protein grams required to go out of ketosis?

    Thank you for your time and effort to help us understand ketosis.
    Roger Oesterling

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  • Raina

    I am a Type 1 Diabetic, have been for 32 years. I recently (about 2 months now) have been following a Keto Diet. At 1st my numbers and the amount of insulin i was taking dropped by more that 50%. During that time I lost about 6 lbs and was extremely happy with everything other than the “keto flu” I was going through. I read more and then started correcting the “keto flu” with electrolights in the form of carb / sugar free power-aid & similar sports tabs. Shortly after however the “keto flu” stopped, my weight stabilized, and my insulin requirements began to climb.

    I don’t understand what has changed other than I’m not constantly dehydrated. I eat mostly dairy fats (heavy cream, cheese, butter), some protein (chicken, lean steak). I started with avocado, heavy cream, cheeses, and lean meats. So minus the avocado, basically the same. My worry is that the ketones are acting as my “sugar” now and thus requiring more insulin to control. Which causes a static state of not losing weight, even though my numbers are beautifully much more level. (Which i won’t trade despite not losing weight, I would just really like weight loss along with beautiful numbers. Unicorn’s right?)

    I haven’t been able to find any real information on type 1 diabetics that have had to increase insulin after going keto. Either I’m 1) not doing something right, 2) not reacting typically, or 3) both? I realize more specific information is necessary to actually find out what’s going wrong, but I don’t know exactly what’s needed. I’m sure you’re busy so my personal situation isn’t/shouldn’t be at the top of your list, but any help/ advice is more than appreciated.

    Thank You,

  • Crystal

    Hello! I have been devouring your posts about the science behind ketosis and diabetes! I have a degree in Nutrition, Dietetics, and Food Science, though I admit, it’s been 10 years since I graduated and I’ve been a homemaker since, so I’m a bit out of practice!

    I must say that most of what I learned about what is “good” and “bad” for you I’m having to throw out the window. When I was in school, the food pyramid was “the Bible” and the USDA was “god”. I have been re-educating myself these past few years as my husband has IBS and I’ve recently been diagnosed with gestational diabetes.

    I have been enjoying your posts VERY much because you actually discuss the biochemistry of nutrition! Finally! Someone who speaks my language (though I’m sorelyout of practice, as I mentioned!) I’m so tired of hearing what’s “good” and “bad” for me because of what the USDA and the American Diabetes Assoc. say, yet no one gives the actual science behind their claims!!!

    Which brings me to my question. I’m trying desperately to treat my GD w/ diet alone. I can’t find anywhere online that discusses exactly why ketosis is “bad” for you during pregnancy. Is it? I mean, I’m learning SO much from your blog about the several BENEFITS of ketosis for the individual. But what about for the unborn baby? Can the baby become ketoacidic from the influx of mother’s ketones? And what if my ketones are “large” (80-160mg/dL +)? Am I ketoacidic based on the standared given numbers for differentiating NK and DKA? I’m struggling to keep my fasting #s in check, but I’ve been seeing improvements since severely restricting my carbs and upping the fat, but it’s still inconsisent. Is there a better way to get that fasting # down? Am I missing something? And is there a way to flush ketones faster so they don’t build up in the blood stream/urine? Is that even necessary? And where does exercise play a role? I read your posts about exercise, but I’m confused. It seems I find everywhere else online that exercising while in ketosis produces more ketones and is not good, yet I’m supposed to exercise to increase my insulin effectiveness and use up extra sugars!

    So much bad info out there and not enough science! That’s why I am SO thankful for your blog! I love that you have a background in medicine, but also have gone above and beyond the standard to actually learn about nutrition-based-medicine and truly HELP people, which is what doctors are supposed to do, right??? 🙂 And I love that you show all the science! So much is coming back to me from my bio-chem days and advanced nutrition classes!! And now thinking of it, we took a pathophysiology class, and it mostly covered nutrition-based diseases and what drugs are often given to “help”! Yikes!

    Anyway, I know this is long, but I have been searching and searching, and the Drs are going to want to put me on meds for my GD if I don’t get it figured out STAT! 😉 Thank you for any help/info you can offer!!!

  • Yossef Gofer

    Dear Peter,
    Thanks for the interesting in inspiring posts. All of them.
    I want to raise a question stemming directly from my personal experience, though i believe that many people may benefit from your answer.
    As much as I’ve searched, I did not find an answer to my question. If it did appear already, please accept my apologies.
    I do not include numbers in order to make things simpler. Just high, low, normal.
    I am diagnosed for hypothyroidism (Hashimoto’s) and treated with eltroxin for more than 20 years. Far from being perfect, but, say, OK. Recently, an endocrinologist suggested to, very slowly, lower the eltroxin dose. The idea is to get close to be hypo, but still within “normal” range. The goal was to improve my well being, which actually degraded. About 1-2 months ago I reached the “desired” levels. Not unexpectedly I gained lots of mass and grew nice round belly. This is one symptom only, but I do entertain others “by the book”.
    I am also diagnosed for hyperinsulinemia with unrecognized reason.
    I am on either LCHF or nutritional ketogenic diet (depends on whose definition one uses). I am on keto NOT for weight reduction. It’s for life, keeping my (previous) OK weight stable. Ketons levels anywhere between close to ketosis, to low end inside ketosis range. Glucose always OK. No hypoglycemia episodes since started keto.
    The questions are:
    1. I have the feeling that being undertreated hypo renders a keto dieter vulnerable to very rapid weight gain.
    2. As much as I tried to read papers on possible correlation between insulin levels and hypothyroidism, all I found was either unintelligible or focused on extreme cases. My focus is on individuals with slight hypo, like undiagnosed and undertreated ones.
    3. Is there any organic connection between hyperinsulinemia and failing with keto diet? (not sure, but I think not associated with insulin resistance). Is it possible that increased insulin levels wrecks the diet and encourage fat storage?
    4. How one with slight hypo condition and/or hyperinsulinemia fits an appropriate LCHF or keto diet?
    Thank you in advance,
    Y. Goffer


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