April 4, 2012

Nutritional biochemistry

What do anabolic steroids, EPO, and carbohydrates have in common?

Read Time 8 minutes

Before getting to this week’s post, if anyone didn’t see the 60 Minutes segment on Sunday about the toxicity of sugar, here is a link to it.  I was pleasantly surprised by what they were able to convey with such time constraints.  In addition to the great work by Dr. Lustig, the very short segment showing Dr. Cantley, highlighting the role of insulin, insulin-like growth factor, and glucose in cancer, is a preview of what I’ll be writing about in the near future.

Back to the topic of the week: What do anabolic steroids, EPO, and carbohydrates have in common?  I know what you’re thinking…what is he talking about?  I’m going to attempt to make the following case today: carbohydrates do, in fact, enhance some aspects of human athletic performance.  So do anabolic steroids, human growth hormone (HGH), synthetic erythropoietin (EPO), and countless other drugs classified loosely and broadly as “performance enhancing drugs.”  The question is, or at least should be, Is it worth using these substances to enhance your athletic performance?

Before we go any further, though, I want to ask you to suspend one thought – ignore the “legality” of these substances.  For example, if we were going to have a discussion about cigarettes and marijuana, I would ask that we have the discussion based solely on their pharmacologic, physiologic, and pathologic features.  The legal issue is actually arbitrary and, frankly, highly illogical at times.  So, let’s take legality off the table.  Carbohydrates are legal and anabolic steroids are not.  Cigarettes and alcohol are legal and marijuana is not.  Understood, but irrelevant for this discussion.

Many people question the logic of reducing or outright eliminating carbohydrates, given the possible reduction in athletic and physical performance.  I’ve written about the impact nutritional ketosis has had on my physical performance, including here, and here.

For those of you not familiar with “standard” performance enhancing drugs, let me digress momentarily to explain what they are, how they enhance performance, and their associated risks (besides being stripped of medals or going to jail).


Anabolic steroids

This class of drugs, broadly speaking, includes a group of molecules that mimic the male sex hormones testosterone and dihydrotestosterone (DHT).  There is a reason, on average, that men have more strength and muscle mass than women, and these hormones play the predominant role in causing this difference.   Exogenous (i.e., supplementing whatever amounts the body naturally produces) use of these synthesized molecules leads to an increase in muscular strength and size when an individual – male or female – combines their use with suitable training.  In other words, taking anabolic steroids and playing video games does not increase your ability to run faster or lift more weight.  You still have to train hard.  However, anabolic steroids provide at least three significant advantages over doing it the “old fashioned way.”

  1. Using anabolic steroids allows you to recover much quicker, and therefore facilitates your ability to train harder than someone not using them.  The mechanism of this action is probably related to their ability to block inflammatory processes in your body.  Ever wonder why you hurt so much after a tough workout (or a long flight)?  Part of it is muscle tearing, which I’ll address in the next point.  Part of it, though, is your own immune system kicking up a fuss via an inflammatory cascade in an attempt to i) prevent you from causing more harm, and ii) repair the damage.  Blocking this process lets you feel better and workout longer and harder.
  2. Through their ability to directly signal at the level of the cell nucleus (steroid hormones go right into the cell nucleus and interact directly with DNA), anabolic steroids also directly increase protein assimilation into muscle tissue.  In other words, they increase anabolism – muscle building.
  3. Finally, anabolic steroids have been shown to decrease lipoprotein lipase (LPL) expression on adipose cells [Translation: anabolic steroids reduce the expression of an enzyme that sits on fat cells and “tells” them to store more fat].  Less LPL on fat cells = less body fat.

Taken together, these physiologic changes make you a leaner, more muscular, stronger person.

So what’s the catch? There is an enormous, and very contentious, body of work around the question of chronic toxicity associated with use of anabolic steroids.  I am not an expert in this, and I won’t pretend to be one.  I have read about it quite a bit and my take is that this field of study is shockingly parallel to that of nutrition, except with smaller sample sizes, worse science (if that’s possible), and even more involvement from Congress (it’s almost embarrassing how much Congress obsesses over this topic with public hearings relative to other problems in our society…but I digress).  If you want to see a fantastic (and highly factual) documentary on this topic, I’d recommend Bigger, Stronger, Faster*.

Chronic use of anabolic steroids is certainly associated with some undesirable consequences, such as increased blood pressure, dyslipidemia (especially reduced HDL-C concentration), acne, premature balding, erectile dysfunction, infertility, clitoral enlargement in women, and gynecomastia in men.

There is a lot of controversy around the psychiatric side-effects of anabolic steroids, especially with respect to depression leading to suicide and a condition commonly referred to as “roid rage.” Most data I have seen suggest anabolic steroids may amplify an already-existing condition but are unlikely to cause these symptoms.  Nevertheless, the side effects of using anabolic steroids are not negligible.

Anabolic steroids unquestionably enhance an athlete’s ability to do virtually anything that requires strength.  I can’t think of a sport where the use of anabolic steroids is not associated with a significant improvement in performance.  But this improvement comes at a cost.  The cost is, for most, dose-dependent (i.e., more use = more chance of side-effects), and certainly not always predictable.



Erythropoietin (EPO) is a hormone produced by the kidney which regulates the body’s production of red blood cells – the cells in our bloodstream that transport oxygen to all tissues and carbon dioxide back to the lungs.  Under normal circumstances the body highly regulates the concentration of red blood cells and hemoglobin. Hemoglobin is the protein carried by the red blood cells that actually binds oxygen and carbon dioxide and allows red blood cells to transport these gases in our bloodstream.  If you donate blood, for example, you are “giving away” red blood cells and hemoglobin.  Your kidneys, sensing this, make more EPO, which signals to your bone marrow to make more red blood cells and hemoglobin.

Blood doping, a practice carried out by athletes at a higher frequency until the development of synthetic (i.e., artificially produced) EPO, is the “messy” way of doing this.  An athlete would have about 10% of their blood drawn and stored a few months before competition.  In the ensuing period of time, their body would naturally produce EPO and return the hemoglobin level to normal.  Just prior to competition the athlete would re-inject their own previously removed red blood cells, giving them supra-normal levels of hemoglobin.  Today, synthetic administration of EPO gives the same result with less hassle.  There are subtle differences between these techniques, including how they are each detected in screening for the drug.

What are the benefits of using EPO?

If the average person walks around with a hemoglobin concentration of 13 to 15 g/dL, boosting that to, say, 17 or 18 g/dL provides a significant advantage in delivering oxygen to muscle cells and clearing carbon dioxide back to the lungs.  Any athlete whose performance is limited by oxygen carrying capacity (e.g., running, cycling, swimming, tennis, triathlon) will experience a great performance advantage using EPO.

The catch? There’s probably a teleological reason our bodies have evolved to regulate hemoglobin levels between about 13 and 15 g/dL.  Anything lower than that and we have less energy and deliver less oxygen to our muscles (though many people do live below this concentration).  But in a very non-linear way, as the concentration of hemoglobin rises above about 15 g/dL (which can occur naturally in a few disease states), the viscosity of blood increases, which directly increases the likelihood of blood clot formation.  In particular, increased blood viscosity is associated with an increased risk of myocardial infarction (heart attack), cerebrovascular thrombosis (stroke), and pulmonary embolism (blood clots in the lungs).  All of these conditions, obviously, can be fatal. While it’s unclear what percent of athletes who use EPO or blood dope suffer these adverse effects, it’s not zero.



Carbohydrates are one of the three macronutrients we consume (the others being protein and fat).  What makes carbohydrates unique is that our bodies can use them under anaerobic conditions.  This means that at levels of exertion so great that your body cannot get oxygen to cells quickly enough for oxidation (use of oxygen to fully harness the energy of fat or carbohydrate), you can still use a less efficient method to extract some energy.

It’s a bit more complicated, though.  You’ll recall from this post and this post, one can still carry out anaerobic activity without actually eating carbohydrates.  How? The quick answer is that consuming protein and fat, even without carbohydrates, generates sufficient substrate to produce glycogen, which is actually what our muscles use during these periods of cellular oxygen deprivation.  Do our muscles and liver contain as much glycogen without consuming carbohydrates?   Almost certainly not.  Are our muscles as efficient at utilizing glycogen in the absence of regular carbohydrate consumption?  Not in my experience.  In other words, eliminating carbohydrates from your diet can be detrimental to some aspects of your performance.  Stated yet another way, carbohydrates are a performance enhancing substance. 

I’m not going to spend any time discussing the “catch” (i.e., the drawback) with respect to carbohydrate consumption (e.g., insulin resistance, metabolic syndrome, obesity, diabetes, cancer, Alzheimer’s disease) since I devote this entire blog to that topic, so let’s revisit the original question.


What do anabolic steroids, EPO, and carbohydrates have in common?

For starters, they all enhance some aspect of your athletic and physical performance, depending on the activity you’re participating in.  Secondly, they all have variable efficacy depending on dosage and genetic/individual factors.  Finally, they all have side-effects, also dependent on dosage and genetic/individual factors.


Is it worth using performance enhancers?

Keeping legality out the discussion, (after all most of us are not Olympians subject to constant drug testing and regulations), should we use anabolic steroids, EPO, or carbohydrates to enhance our physical performance?

It depends.  Again, let’s keep legality out of it to normalize the discussion.  If your goal is to win the Tour de France, should you use EPO and some form of anabolic steroids?  It’s very hard to imagine how anyone, regardless of natural ability and training, could do what is expected of these athletes without some supplemental chemistry.

What if you want to be a starter in the NFL? Hit more home runs than anyone else? Set the world record in the 100-meter dash? I’m not saying you must use performance enhancing drugs to do these things, but it sure helps.  Furthermore, if anabolic steroids, EPO, and other performance enhancing drugs weren’t actually illegal, I’d be willing to bet their use would increase dramatically among both professionals and non-professionals.  [Non-professionals – i.e., “normal” folks like you and me – far outnumber professionals in the use of performance enhancing drugs, probably by over 10 to 1.]

I will pass no judgment on anyone who chooses to use anabolic steroids or EPO or carbohydrates to enhance their performance.  I will also pass no judgment on folks who use marijuana to ease their pain or to relax.   As I said earlier, I think the legality of these substances is arbitrary.  Cigarettes and alcohol are ok, but marijuana and anabolic steroids are not?

Everything has a tradeoff, which is exactly why I don’t like being asked, “Hey Doc, what should I be eating?”  How should I know?  It’s as illogical a question as, “Hey Doc, should I be using anabolic steroids?” If you are aspiring to win an Olympic medal (again, assuming all performance enhancers were legal), the answer is probably, “Of course you should…and while you’re at it, add some human growth hormone!

You want to win the NCAA championship in the 200 yard freestyle?  Ketosis is probably not for you.  Sure you can (and should!) restrict sugar, but I think you’d be better off consuming, say, 40% of your calories from rice and non-wheat, non-sugar starches.

So why am I in ketosis, even though I might “perform” better at some things if I ate carbohydrates?  Because I’m a 39-year-old wannabe athlete whose athletic performance is irrelevant.  Not a single person cares how fast I swim or ride my bike beyond myself.  I have no sponsors. I will never earn a paycheck for how fast I can flip tires or climb Mount Palomar.  I am more than willing to give up some athletic performance (e.g., sprint speed, peak power) in exchange for other athletic benefits (e.g., greater aerobic capacity and metabolic flexibility), especially when the real gain is greater health and a reduction in my risk for all diseases associated with metabolic syndrome (heart disease, diabetes, cancer, Alzheimer’s disease, and others).

Can I tell you what to eat, what to drink, what to smoke, or what to inject?  Perhaps, though I’m not sure how relevant it would be (or why you’d want to listen to me).  What I really want to do is at least give you a sense of how to think about the tradeoffs involved in each of these decisions so you are better able to make the right decision for yourself about what to inject or what to eat to enhance your performance.

By melvil (Own work) [CC BY-SA 4.0], via Wikimedia Commons

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  1. Dr. Attia,

    I disagree about treating carbs the same as PEDs, for two reasons:

    1) “what this blog is about” is the damage of consistently high carb intake, all day every day; timing your carbs to sync up with exercise may be completely different. (there may also be damage specific to insufficient fat intake.. but I digress.)

    2) Our ancestors ate fruit in the tropical zone for millions of years, didn’t spread to the temperate zone til 40kya, and started eating carbs on a regular basis again 5-10kya.

    I took 4 inches off my waist after reading GCBC, and I’m grateful to GT for his work. However, although most people do best on a diet with less than half of total cals from carbs, I think ketogenic is inappropriate for the vast majority.

    If people are going to get more than 50 g carb most days, it becomes even more important to sync that carb timing with exercise.

    • Jeffrey, I think you missed the point of this post, which reflects much more poorly on me than you, since I wrote it. I apologize. At no point in this post or others do I suggest everyone should be on a ketotic diet. Yes, I am ketotic, and after a 2 year self-experiment of gradual carb reduction I’ve found the benefits (e.g., mental acuity, sustained energy levels, reduction in disease risk) outweigh the costs (e.g., loss of some physical performance, “difficulty” of getting 80-90% of my calories from fat). If you’ve been following my blog, and you’ve read the work on Volek, Phinney, Steffanson, Schwatka, Eades, Sisson, and others, you’ll note that at least some individuals CAN in fact do the most strenuous exercise without any carbohydrate ingestion (i.e., <30-50 gm/day). In particular, the work of Steffanson and Frederick Schwatka is particularly remarkable for the study of the Inuit population -- a population that ate zero carbohydrate and carried out a life far more physically demanding than anything we do. However, this issue was not the point of my post.

      Here is my point: Carbohydrates improve physical performance. So do anabolic steroids and EPO. Carbohydrates have side effects. So do anabolic steroids and EPO. Does it mean we shouldn't use EPO or anabolic steroids or carbohydrates (ignoring the highly arbitrary and illogical legality of anabolic steroids and EPO)? No it does not. It means we need to balance the costs and the benefits of what we do. If being a little faster on the weekend ride or the pick-up game matters -- and if it does, that's fine -- they maybe one should be ingesting more carbs. It's just completely illogical to think that doing so is completely benign or that doing so is somehow "smarter" than using anabolic steroids.

      I'm not talking about "abuse" of anabolic steroids or EPO. No doubt you can more quickly and profoundly demonstrate the toxicity of these agents than that of carbohydrates, but most people who use anabolic steroids and EPO do just fine.

      I completely understand your point about timing and ways to mitigate the deleterious effects of carbs. But that is no different than what an athlete does when they cycle on and off different anabolic agents -- they are optimizing performance while trying to minimize risk.

  2. Hey Peter,

    Seriously impressed with this site and your work.

    I’ve my own ideas on diet as it relates to health and performance, but we’d share many common themes.

    My concern isn’t really longevity but performance at soccer. So I need bursts of speed and endurance.

    I also like having a relatively normal diet so I don’t feel like I have to be obsessing over food and too picky. Some people don’t have this issue, but I do.

    Also, a lot of the positive results you’ve experienced are also gained by people that simply lose weight, by any method.

    I’ve used intermittent fasting myself (24 hrs once or twice per week) and the health markers are proven to drastically improve with a big reduction in body fat. So that has big longevity benefits in itself.

    However, I’ve no doubt that a high fat, balanced protein and lower carb intake is better for health and performance.

    Are you aware that fats drastically improve the endocrine system? Male testosterone is hugely improved by high fats by SHBG (Sex Hormone Binding Globulin). Your results could be as much to do with these factors as removing carbs.

    I try to start the day with two tablespoons of coconut milk, fruit and a protein. That way when I control calories with intermittent fasting I’ve cut carbs and not fat and protein, thus changing my diet to maybe 40% carbs and low calorie.

    Fasting also greatly improves the process you talk about, hormone balancing, insulin reduction, insulin sensitivity etc.

    All improved by losing body fat but fasting amplifies the effects as well.

    So I’ve a different take, but many similar themes. I find it easier to live my way and I like that I have a base of carbs for anaerobic bursts of power.

    However, an awesome site, continue your great info and studies. The exact figures and studies you’ve done are especially informative and impressive. Well done.

    • I just want to edit the above post a bit. I was a little off hand in describing how I eat at breakfast.

      My first eating of the day has more fat than just two tablespoons of coconut milk.

      I also have a tablespoon of cod liver oil, two tablespoons of chia seeds, a superfood supplement of fruit and veg called ‘source of life gold’ which is low calorie and unbelievably comprehensive and nutrient rich.

      I often eat eggs as well.

      And then I have about 50 grams of protein in a shake called nitrofusion (plant based)or some type of chicken because I like to have an intake of 70-140g of protein per day due to my training regime.

      For the rest of the day I eat low calorie and medium level of carbs with one or two 24hr fasts per week.

      I’m convinced high fat, calorie control and calorie cycling (fasting and ‘big’ feeds) has major positive effects due to our genetic profile/evolution.

  3. I know you say people can have a different genetic response to diet but if you were to become a sprinter, what diet would you have?

    Would it be 40% carbohydrate all the time or would you only use generation ucan prior to an event and after?

    Or carb load on generation ucan generally on and reduct fat intake accordingly?

    After reading your posts I am interested to hear your thoughts on this.

    • Thanks man.

      And sorry if you felt I was launching on you a bit.

      I couldn’t edit the thing to sound a bit better as it didn’t give me enough time.

      I’m really impressed with this site.

  4. Peter, this isn’t exactly on-topic. It’s about optimizing your sprinting capacity. In your last comment, you said you’d go with 40% carbs. If you’ll indulge me, I’ll show you why that’s the wrong way of looking at the problem.

    Sprinting is not about fuel efficiency, but about power output. Take a car for example. Everybody knows a small engine is more fuel efficient than a large engine. It makes sense. A small engine is lighter, therefore it needs less fuel to get the car moving. But the assumption is that a small engine will go in a small car. If we put a large engine in the same car, but keep the total weight the same, both the large and small engines will be just as efficient. That’s because fuel efficiency is not determined by the size of the engine, but by the ratio of total resistance and power. For equal resistance, we need the same power, therefore the same amount of fuel. Granted, a large engine has bigger moving parts therefore more internal resistance but the difference is marginal compared to the differences between a small car and a large car.

    Sprinting is about acceleration. So while a smaller engine might be more efficient for steady-state, it just doesn’t cut it for finish-line acceleration. Yet a bigger engine isn’t that much less efficient for steady-state. In fact, it could be more efficient by virtue of having more power, therefore needing less effort for the same steady speed.

    Talking about carbs for sprinting is like talking about nitro for car engines. It works but it comes with its own set of problems.

    The real problem? Muscle size. Solution? Bigger muscles. Since we’re talking about only a small portion of total body weight – the legs – the potential increase in power output probably more than makes up for the potential increase in weight. It’s like putting in a V6 that puts out 300hp, but weighs only 100 lbs more than the inline 4 that puts out 200hp, in a car that weighs 2,000 lbs. For a human male, that would be like adding 5 lbs of leg muscle, in a body that weighs 180 lbs. And then consider the fact that dietary fat weighs half and doesn’t detrimentally affect hormones as carbs do, running out of fuel mid-race is not a problem even though bigger muscles need more fuel.

    My own experience seems to confirm the idea of bigger muscles to improve endurance. I play golf. It takes endurance to walk the course. But it also takes strength for every stroke. Halfway in the round, I’d get tired and didn’t have enough strength to perform the motions with as much precision so my score suffered. I decided I’d get stronger first. It gave me more endurance for some reason. Since I was stronger, I didn’t need to exert myself as much. I’d stay fresh the whole round, and I had enough strength to the end, my score improved. I also ate a quarter pound of butter for lunch.

    Basically, endurance capacity as a function of strength/effort. And sprinting capacity as a function of pure strength.

    • Addendum. About 5 minutes ago, I read a post on lowcarb.ca forum from PJ. She said something about exercise-induced asthma. It got me thinking. First, check this out:


      The idea with this drug is to reduce the number of fat cells to grow leaner. Fat cells, like any other cell, need oxygen. More fat cells, more oxygen. But fat cells don’t give us strength, endurance, and basically don’t do much besides supplying us with a steady stream of fuel. If we have more fat cells, they consume more oxygen for no good reason. This oxygen could be used instead by all other cells to give us strength and endurance. More fat cells also means more fuel supply to all other cells but also more oxygen needed for oxidation by all those other cells. Basically, being fatter means oxygen deprivation for all other cells.

      Oxygen isn’t only needed for strength and endurance, but also for health. Everything that keeps us alive needs oxygen to work. If we’re fatter, there’s less oxygen for that. In the monkey study, they showed health improvement when their fat cell count was brought down. It makes perfect sense.

      Anyway, for sprinting optimization, reduce your fat cell count. Less oxygen to fat cells, more oxygen to muscle cells, more strength, more endurance. Brilliant.

    • Good points, but I guess it depends on how we define “sprinting.” Because I’m kind of an ultra-distance wonk, “sprinting” for me is probably middle-distance for most. In swimming, a sprint would technically be the 50, though I’m really talking about optimizing around the 100-200, which is far less CP and almost pure anaerobic.

  5. Hi Peter,

    Loved the post. Learning about this stuff from your blog and references is like drinking from a fire hose. Had a question regarding your on bike nutrition during a long bike ride. My first long, hard group ride after my high fat, moderate protein, low carb breakfast didn’t go too well. The next time I ate a big bowl of sugar cereal and drank sugar-water the whole ride … much better. But I don’t want to derail my keto-adaptation from the week and keep yo-yo’ing. What do you eat (if anything) on your long, hard bike rides?


    PS. I’ve had some random thoughts on your blog which I’d like to share. It’s kind of a grab-bag.

    1. Please monetize your efforts to at least cover your costs. There are a number of people making a living doing what you’re doing. Would hate to lose you due to the financial burden it places on you and your family.
    2. Is there any data out there that shows increasing blood sugar or insulin for a large number of people over the decades? The United States Military has tremendous data from all recruits which spans decades. Their data shows alaming trends in size and physical fitness of recruits. I assume they have no blood data but I’m curious.
    3. My niece just graduated from med school. We talk nutrition at Starbucks while she drinks a carmel-machhiato and I have full cream latte and we both look at each other like we’re crazy. You mentioned somewhere that if 20% of physicians would buy into low-carb as an effective and safe modality to try with their patients that that may be a tipping point. Why not get to the source and try to get med-schools to teach low-carb instead? I’m sure you’ve thought of that but wanted to throw it out there.

    • Eric, Ketoadaptaion takes months, if not weeks. Certainly not days. Once you’re “there” you don’t need much on a long ride. I eat some salted nuts for sodium and fat and individual packs of cream cheese.
      I appreciate your thoughts on monetizing the blog, but for now I’d like to keep this as free and clutter free as possible. I will ask something in return, but that’s for another time. Not much observational data on insulin levels, since they are not routinely measured. As for #3, this is a small part of a much larger goal of NuSI. Many steps needed, first.

  6. With regard to performance enhancement in general, do you have any opinions on creatine supplementation while on a ketotic or general carbohydrate-restricted diet? It seems to be a generally-accepted notion that you need an insulin spike accompanying the creatine load for maximum benefit, but I am skeptical.

  7. Peter, I am new to you and your blog, but not to Taubes, Lustig, et al and their great work regarding sugars, carbs, etc. This post seems the best place to ask my question. I’m a personal trainer, group fitness leader, and (recovering) public health professional. I’ve been taking people outdoors for their exercise since 2003 and am curious to know what you think of a performance enhancer about which I haven’t found any discussion on your site: nature and sunlight. Are you familiar with the research on the added effects on our mental and physical performance and health when athletes and nonathletes are active outdoors? Do you lend much credence to it? I’m not aware of any research related to weight/fat loss, but it seems here too there might be an additional effect, via the stress/cortisol/insulin connection. The thinking is that we evolved to be outdoors in sunlight, much more than we currently are, and this is having health consequences (see especially the books by Richard Louv on nature deficit disorder and by Eva Selub on nature and the brain). Deserves its own post, I think.

    • Nancy, I’m especially knowledgeable in this subject, but it’s hard to make an evolutionary case that such factors don’t matter. Check what Mark Sisson or Robb Wolf have to say.

  8. Ketone Help. I started LCHF 7 weeks ago. Immediately dropped 10 pounds and need to plateau as it continues to decrease, now a t 161 from 175.. I’m super active cycling and working out 5 to 6 days a week.I got the meter and tested Glucose (out of curiosity) 20 min after a meal sugars at 70, the next day (yesterday) tested Ketones mid day 0.3. Today I blood tested first thing in a.m. and Ketones are 0.6, which sounds very low. I appear to exhibit all the signs of being in Ketogenic state, no food cravings, frequent urination (which is decreasing, thankfully) was keeping carbs less that 50 per day, now somewhere between 50 and 100. Extra are pre, post and during more intense cardio. work (2 to 4 hours). I’ve definitely lost strength in regard to cycling, hoping it will return??
    What does low Ketone blood measure mean in regard to Ketogenic state?
    What other fats can I eat to avoid continued weight loss (I may be eating too much protein now?)
    And the big question, how does the body utilize fuels in an Anaerobic state if there aren’t adequate sugars availabe for fuel???

    Thanks for any input…

  9. I’ve just discovered your blog and I find it amazing! I’d say that I’m more or less like you, with the difference that I do not have any medical background, just the data I read everywhere, but we seem share the very same concerns about finding the perfect way to eat healthy. I’m a 29 year-old software engineer. Until my first 20ies I’ve never done any sport and were eating only crap, of course full of sweet and carbs. Then I started bodybuidling and that alone made me improve a lot and become stronger and leaner. Then I started to care about nutrition and also began eating “well” and I put it this way because I’ve been following the common practises of “low-saturated-fat/high carb/high protein” typical in body-builder diets. 3 years ago I started to enjoy participating endurance races and now I can say I’m a lot more into endurance running than weight training but I maintain the two. I’m 172cm tall and 62 kg with 11% bodyfat or so I think.

    It has been several years now that sometimes (pretty randomly indeed) I felt very tired, bad mood, irritable, and very spaced out, light-headed. I went to the doctor but the blood tests showed pretty normal. Also recently starting last year I started to feel like numbness in both hands and feet. I did my research and being worried by a possible kind of neuropathology due to excess carbs I started trying to reduce them and even if I find hard to get under 100gr a day of carbs (I’m a vegetarian for personal believes so no meat/fish/whatsoever is alive, dairy, eggs and derivates are ok) I can tell I’m feeling better recently.

    The only problem now I see is that my athletic performance has been decreasing a lot this year. Last December I ran a PB on the 10K with 35:25 and managed in some other races to get 36 or low 37. But recently I’ve felt a very hard impact on performance, now I struggle a lot just to run in 38′ and I have the feeling that the carb reduction (even if not near the 50gr day to enter full ketosis) may be the cause. I’ve also been diagnosed with a little bit of aenemia so difficult to say if one, both or any may be a cause.

    Well, that’s my story. I’ll keep an eye on your blog and maybe keep you informed about my observations on the subject over time if you may care.
    PD: Sorry for my poor english.

  10. Peter,
    Thank you for your invaluable commentary, and open minded approach to the topics you discuss.
    I have a couple of questions:

    1) You mentioned in a response to one post that ketogenic adaptation can take months. After starting a ketogenic diet in May 2012, I noticed that when doing my 4 mile run that I would have much greater energy after a “cheat” day in which I consumed large amounts of carbs. Now, after being on ketogenic diet for 7 months, I don’t get that same performance enhancement effect after a “cheat” day. Would this be explained by having more fully completed ketogenic adaptation? As a follow-up, I also notice that I feel sort of depressed after a “cheat” day. Do you think this is somehow related to serotonin levels/regulation?
    2) I have noticed that I can remain in ketosis (tested using ketostix) and eat a relatively large amount of natural peanut butter, and raw nuts such as cashews, pecans, and almonds – sufficient quantities for total carb intake to approach 100g/day. Is there something in peanut butter/nuts that effects carbohydrate metabolism, or is it more likely that my body chemistry simply allows me to eat these quantities of carbs and remain in ketosis?
    3) You discuss B-OHB levels in some of your posts. Is there a simple testing method for B-OHB? Ketostix measure acetoacetate, correct? Is B-OHB level a more reliable measure to determine one is in ketosis? Why?

    • 1. I don’t know. Would need to know a lot more to even hazard a good guess.
      2. Not sure, but timing of consumption and activity level may have something to do with it. Nuts don’t stimulate much insulin in most people, so that may play some role.
      3. Blood B-OHB is the gold standard for measuring ketosis.

  11. Peter- is there a “best” alcohol in your opinion for keto? I’ve had this argument (over drinks) with many friends and so many opinions– beer vs. red+white wine vs. hard alcohol incl. whiskey vs. vodka vs. tequila etc. Any advice for social drinkers?

  12. Hi Peter,
    I’ve been on a keto diet for 6 months now and it’s the best decision I made in my life. I recently started weight training and I want to take the max out of both worlds. Can I add for example around 100g of carbs before my workout to be used as energy for the workout and keep my carbs as minimum as possible in my non-training days ? Do you think this way I can have maximum performance and still keep the healthy benefits of staying low-carb ? And will this ruin my keto-adaptation ?
    I wouldn’t think about carbs to enhance my performance but I’m very skinny and I have to gain weight. Body fat is not an issue even with my prevoius high carb diet my body fat was veery low.

    • It’s possible, though I don’t consider myself an expert in this particular issue of maximizing hypertrophy in ketosis. Give it a shot and track all the data you can. You will need to closely monitor B-OHB levels to know if you’re “in” or “out.” See the posts (2) on the interplay of exercise and ketosis.

  13. I miss your posts……..anyway .I was wondering what your thoughts as are on if excluding carbs from your diet has any negative effects on Testosterone. LH, FSH etc and other hormones compared to including them? Being Ultra low carb vs including some. Usually the anti-lowcarbers harp on ketogenic diets causing adrenal fatigue and extreme cortisol levels and all types of things.. what are your thoughts or guess for someone trying to optimize their hormones and build their physique?

    • Many people actually experience the opposite, especially if transitioning from a “standard crappy American diet.” LH and FSH in a snapshot don’t tell us much, free certainly free testosterone does.

  14. Not meaning to revive an older blog posting, but Dr Attia, do you know of any synergistic role of testosterone and hgh on activating abdominal HSL in humans (in order to decrease visceral adiposity)? I think this was true in mouse studies, not sure if was validated in humans. Of course, I get the science of firstly reducing circulating insulin to keep LPL levels low and thereby hopefully increasing HSL and in turn mobilize abdominal fat… just wanted to know if the actual physiology of hgh in this capacity was known in humans ….

  15. Hello petter, I am charmed with reading his blog .. I want to know that he thinks of the civilization kitava.? They feed in 70 % of carbohydrates

  16. Instead of taking EPO, why don’t athletes do a combination of
    (1) training for 2 months before competition at very high altitude,
    (2) drain 1 to 2 units of their blood 2 months before the competition and re-transfuse it back a few days before the competition, [The blood volume can be halved and re-infuse the packed cells minus all the plasma].
    (3) Breath supplemental OXYGEN shortly before the competition,
    (4) Have a good carbohydrate last meal before the competition.

    (1) & (2) will increase the number and oxygen carrying capacity of the athlete’s blood WITHOUT and evidence of EPO.
    (3) & (4) top off the performance ability and make best use o f (1) & (2).

    I don’t know if any athletes take advantage of these methods of enhancing performance but if my livelihood depended upon my athletic performance, I’d look into these activities which cannot be detected by any blood or urine test. Using detectable EPO is plain STUPID when the same results can be obtained naturally. Training at high altitude simulates one’s body to produce more red blood cells and re-injecting one’s own packed blood cells cells from one;s own transfused blood does the same. Breathing pure oxygen just before competition ensures the maximum oxygen in the blood at the time of competition. Carb loading is popular among athletes. It’s the least effective of the above three.but it’s as normal as having breakfast.so why not?

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