Kurt G. Harris MD

PāNu means paleonutrition. The "paleo" here signifies "old" and not necessarily paleolithic. The PāNu approach to nutrition is grounded on clinical medicine and basic sciences disciplined by knowledge of evolutionary biology and paleoanthropology. The best evidence from multiple disciplines supports eating a pastoral (animal-based) diet rather than a grain-based agricultural one, while avoiding what I call the neolithic agents of disease - wheat, excess fructose and excess linoleic acid.

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« Optimal Nutrition by Kwasniewski | Main | How to Lose Weight »

Can protein turn into fat?

I've had a lot of questions and comments about dietary protein and what happens to it, particularly when one is on "zero carbs". Here are some thoughts:

1) If your body is in glucose deficit and you are not getting enough dietary glucose, then gluconeogenesis will supply the glucose. Short term deficits, however, are met by making glucose from the glycogen in your liver, not by breaking down proteins. A simple fall in serum BG does not crank up the GNG machinery. GNG happens to replenish your glycogen, not after a single weight lifting session, just if there are no carbs by your next meal and your liver glycogen has been run down too far.

2) If glycogen stores are depleted and need to be rebuilt, they will be replenished from dietary glucose first. If there is not enough dietary glucose, dietary protein will be used (60% or 70% conversion ratio, pretty close) next. If there is not enough dietary protein (amino acids actually) then existing structural proteins in your body will be used to supply the amino acid feedstock for GNG to make the necessary glucose. Please remember that what is really happening is that proteins are constantly turning over into AAs in your body all the time. If you are deficient in dietary protein (no protein bolus at the next meal) , they are broken down and then are not being re-built. You are not directly scavenging your muscles, you are just failing to re-build them. Proteins and even fats are not static. Gaining or losing muscle or storage fat is a dynamic equilibrium process controlled by hormones, etc.

3) Protein eaten in excess of structural and enzymatic (our enzymes are proteins) needs, and in excess of GNG requirements if you eat no carbohydrates, can be burned as fuel for energy. This is why we say that protein has a caloric value of about 4 kcal/g, just like glucose. If it is burned as fuel, that is the energy density. There is no " every gram of protein turns into such and such" It depends on many variables.

4) Any macronutrient with caloric value (carb, protein or fat) can be burned for fuel. Any of these can also be stored as fat if they are in excess. Note I said, "can be" stored as fat. Insulin is the nexus of processes that end in fat storage. If insulin levels are lowered from your previous baseline, fat storage is inhibited (remember the equiibrium?) so you tend to lose fat down to a new equilibrium. You will tend to stay at that new equilibrium based on in my opinion, two things: spontaneously lower caloric intake and possible increased wastage or burning of any excess caloric value. (See your bible: GCBC by Gary Taubes)

The reason dietary proteins are less likely than carbs to end up as fat is the same reason dietary fat on VLC is less likely to end up as fat. It is not because they can't be converted to fat. Of course they can! It is because eating fat and protein and very little carbs keeps your insulin levels low, get it?

Once again, macronutrients influence hormones, and it's the hormones that direct fat storage.

Think how food affects hormones, not whether this or that food component "turns into fat".

Food only turns into fat at the direction of hormones.

Hormone levels (AUC or area under the curve) can be stable within a range of different macronutrient ratios. Your insulin levels in particular only drop so far. That is why I say repeatedly it is not biologically plausible that most people need to tightly define their macronutrient ratios, anymore than it is biologically plausible that you need to use a scale and a calculator to regulate your weight. 

Like natural gas, oil and coal in the industrial environment, carbs fats and proteins have specific structural uses in our bodily environment, but each has a potential value (not required, but potential) as fuel to keep the metabolic fires burning. Natural gas is both a feedstock to make plastics and a fuel that can be burned. Oil can be used to coat your driveway or turned into gasoline for your car.

There is not any "typical" thing that always happens to a molecule of glucose, fat or protein. It depends on what the body needs.

As far as raising your insulin levels, glucose has the biggest effect, and fructose is bad because it induces insulin resistance, which requires you to produce higher levels of insulin to handle the same amount of glucose. Protein requires insulin but less than glucose and there is some insulin response to dietary protein. There is no insulin response to dietary fat. All three require some basal insulin for normal metabolism.


Reader Comments (35)

Hey Kurt

Awesome blog, loving it. It's a great one to forward on to folk who are new to all this. Glad to have been here when it started!

I'm glad you posted on this topic because lately I've been thinking: why do I seem to have gained belly fat after going VLC - LC? (Started in earnest at least 3 months ago.) I'm about 190cm but have always weighed between 65 - 70kg. Just one of those skinny dudes. Haven't worked out much since going LC either (I know, I know, you don't have to tell me... ) BUT started a course of SSRIs when I began LC - I'm now coming off them, slowly. Could this perhaps be a side effect of the Citalopram? Or, given my slight mass despite my height, could I just be eating way too much protein, considering I don't work out right now? Could 1g of protein per kg of bodyweight actually be too much for a tall but (currently) lazy, skinny guy like myself? It's been very easy for me to 'accidentally' go over 70g as I LOVE eggs, meat and raw cheeses... you know how that goes I'm sure. I know that if I start running and KBing again perhaps things will look a little different...



August 27, 2009 | Unregistered CommenterTaliesin

Further to Taliesin's post above; what if he wanted to increase lean body mass (muscles)?

Someone asked in a prior post of yours how to add weight and you countered "why would you want to add weight?".

However, if someone (for cosmetic or other reasons) wanted to increase their lean muscle mass how would they focus on this in the realms of PaNu? Mark Sissons has suggested the Vince Gironda staple of adding a dozen eggs a day, so is it just a case of more protein if you're an actively weight training / bodybuilding?

Love you site and keep up the good work!


August 27, 2009 | Unregistered Commenterwinalot

I'd also like to ask you about SSRI's, such as Citalopram, and their effect on insulin secretion / sensitivity?

Perhaps a post dedicated to PaNu, depression, eating disorders and anti-depressants sometime? :-)

August 27, 2009 | Unregistered Commenterwinalot

One question regarding point number 4: "If insulin levels are lowered from your previous baseline, fat storage is inhibited". Well what happens with all the fat in the diet? Let's say a person caloric need is 2500 calories/day and he eats as you recommend (i.e. No carbs, Enough protein, lots of fat), but the daily caloric intake is 3000 calories. Since no insulin is secreted, you argue that this person won't get fat. I argue that the intestine is "greedy" and will absorb all macronutrients it can, and my question is, where all the excess energy goes? I think that NEAT (Non-Exercise Activity Thermogenesis), higher thermoregulation set point and more unconscious activity can not explain this (Since I can argue the same about 4000 calories). I would like to hear your thoughts.

Keep on with the blog, I really enjoy reading it.

August 27, 2009 | Unregistered CommenterOsher

@Osher- while I can't give you the nuts and bolts, I can tell you (for me at least) there's more to it than number crunching.

After tracking every morsel for awhile- a calorie is not a calorie. Almonds and Pistachios- somehow don't seem to pack the same punch as fruit. I can eat 2-3 times the calories in nuts as fruit, all else more or less equal.

And zero cal diet soda- somehow tends to make the other calories count twice. I know, an observational study of one, hardly scientific, but try it for yourself.

I can regularly eat more than my "prescribed" calories, sans weight gain, when the excess intake is primarily fat. (Note this only works for ~50g or less carbs/day - any more and the excess water weight skews the data).

August 27, 2009 | Unregistered CommenterGreg

winalot - Check this out


Anyone know how accurate these statements are?

Sorry to veer off post Kurt - I second winalot's suggestion for a future post some time on this subject though, if it's something you have ideas about yourself of course. While a lot of people will have arrived at places like WAPF and the various Paleo approaches from a deep concern for their physical health (obesity, diabetes et al) I for one have had a lifelong interest in finding the 'truth' about diet out of a desire to simply feel better psychologically. Surely the abandonment of EM2 has contributed to the prevalence and increase of depression / anxiety / eating disorders in our world as much as it has to the more overtly visible physiological manifestations of the 'diseases of civilisation'?

Sorry again for hijacking the thread!!!

August 27, 2009 | Unregistered CommenterTaliesin

Thank you for your reply and while I appreciate your experience, this logical hole the low carb theory really bothers me. Where are all the calories from fat are going to? I can eat 5000 calories of fat daily with no carb (and enough protein) what will happen with them? Interesting question.

Thanks again, I will continue to follow your highly informative blog.

August 27, 2009 | Unregistered CommenterOsher


As i understand it all fat consumed is entering adipocytes. The difference being how easy the fat can enter and exit the fat cells. Calories ultimately still count.

August 27, 2009 | Unregistered CommenterDanny Roddy


I don't see a logical hole. Are you saying you are at the same weight eating 5000 calories a day for 6 months, then dropping to 2000 you will stay the same weight? I seriously doubt that. Perhaps I misunderstood your post.

The increase in fat percentage works primarily by increasing satiety and you are spontaneously eating less. Secondarily, there is probably a "metabolic advantage".

I have never claimed you can go from 2000 to 5000 kcal /day and not gain weight. I have never claimed you will not gain weight if you purposefully overeat. I do claim most people can lose weight without measuring. That is quite obviously not the same as saying it does not matter what you eat.

It is reasonable, though, to think that if your insulin levels are stable your weight could be the same eating 1800 kcal/ day as 2100, though. That in fact is my exact experience. I suspect the extra fatty acids, AAs or even carbs are burned off in a purposefully inefficient fashion or otherwise wasted if they are not needed.

In fact, that must necessarily be the case, or else how could anyone's weight be stable over time without measuring?

Calories count outside certain ranges the same way macronutrient ratios count outside defined ranges.

If to prove a point you force yourself to eat extra fat despite not being hungry, or if you have a hypothalamic tumor that makes you insatiable, though, calories will probably start to count.


Sorry, I am not a cosmetic bodybuilding expert. Genetics, diet and training determine body composition. The idea of making muscles look a particular way (vs perform) has no appeal to me so I don't really know much about it. In the same way, I have no idea how to achieve some arbitrary scale weight that is not what your genes and diet determine and I can't understand what the utility of doing so would be (unless you are jockey or competitive wrestler). Maybe I am biased by my rock climbing history years ago. There the whole point is strength to weight ratio, and climbers are indifferent to looking like bodybuilders.

Re: SSRIs and weight, diet and mental health

Perhaps a future post. Many drugs can throw a spanner in the works.

I know there is good epidemiologic evidence linking bipolar disorder and major depression to 6:3 ratio.

I believe it is quite likely schizophrenia is caused by eating gluten grains.

I've heard anecdotal reports of improvement in anxiety symptoms with many LC or VLC regimes, probably due to more stable BG and hence less epinephrine related to hypoglycemic overshoot. If you ever find a food that prevents your heart racing when opening a letter from the IRS, let me know!

Eating disorders is a good point. Some folks can never give up sugar or wheat because it is their drug. That is, they are not just physically addicted. The usually unwanted side effects are part of what they subconsciously seek, in the same self-destructive way people do a variety of really stupid behaviors they consciously know might kill them. Psychologist Robert Firestone (a big influence on me, btw) calls this "microsuicidal behavior" - the damage is precisely the point for some people.


Perhaps more accurate to say that there are always patrons entering and leaving the bar and that determines how many are in there drinking at one time. However, not all potential patrons who walk past go in, even if there is net inflow and the bar is filling up.

August 27, 2009 | Unregistered CommenterKurt G. Harris MD

just some scattered thoughts...

i think they body is going to choose persay its own ideal weight, like Kurt said based on diet, genetics and body muscle. i dont think that people can MAKE themselves a certain way unless they are consciously doing so. you shouldnt have to much to "think" about eatign this way. the choices are simple, theres no head game or real portions/percentages involved. eat high fat, moderate you protein and throw in a couple carbs from eggs and such. you can step on the scale every morning to see what you weigh making sure you dont "go outside" you comfort territory. but thats so not necessary. if you eat when your hungry, and eat according to PaNU, your body will do what it's going to do regardless of what you think the scale "should say"

as a recovering anorexic- i can vouch, although my situation is probably different, that when you eat this way, regardless almost of how much or little you eat, your body will keep what it wants. you will gain if you need to(like me) and lose what your body does not need(as in most people reading the blog). overthinking and stressing the whole diet mantra will really keep you from losing the weight you want to, and keep you from experiencing life itself. maybe thats why kurt isnt to gung-ho on posting meal plans, daily food and the such. you know what real food is....eat up

if you exercise 24/7 like a fanatic, your most likely going to hold onto a lot more weight b/c you body is preparing itself for the needed exertion you perform obsessively.

re- the diet soda... that was the hardest thing for me to give up ever... i was addicted to the need for "sweet" which obviously couldnt be a good thing. but i have been diet soda/artifical free, only drinking water since march i think. if your so into the optimal health produced by PaNu, why are you consuming artifical sweetners to begin with? just a thought...

August 27, 2009 | Unregistered Commentermallory

Well, I got my answer. I thought that you and other advocates of the LC diet claimed that calories don't count as long as one keeps the insulin levels low. but:
"Calories count outside certain ranges" is the asnwer I was looking for. So one must keep his insulin levels low and eat reasonable amount of calories.
This statement arises another two questions:
- How much is reasonable?
- Is your claim of "spontaneously eating less" on PaNu diet is scientifically proved.

I learn much from this discussion. Thanks.

August 28, 2009 | Unregistered CommenterOsher


If you have a "broken metabolism" you may have to get into ketosis before your appetite can be relied on to regulate your caloric intake.

Your body will be able to tell what it needs just like it can tell how much to breathe.

I would estimate 90% spontaneously reduce their intake with no discomfort or counting at around 15-10% carbs.

If you have a spare million dollars, I'll apply for a grant and then we can "prove it".

Or you can just try it and see how it goes.

August 28, 2009 | Registered CommenterKurt G. Harris MD

Well, I don't have any spare million dollar but I don't like the quotation marks around "prove it". Guesstimations and "Just see how it goes" rank well bellow expert opinion in the evidence level scale. I was under the impression that evidence based medicine and scientific methods are the driving force of this and other nutritional sites. A simple answer like I don't know how many calories are reasonable and no, not all my claims are scientifically proved is good enough answer. Nutrition is understudied field and good research is hard to find.

August 28, 2009 | Unregistered CommenterOsher

I think we're looking at the subject from two different points of view. You say "Your body will be able to tell what it needs just like it can tell how much to breathe". I say, of course the body knows how much to breathe, but doctors can measure FEV1, TV, PEF and many other parameters related to pulmonary function and use this knowledge in scientific and medical applications. So I wondered if similar measurements exists for the nutrition field, which was my question - How much is reasonable amount of calories and is it scientifically proved.

August 28, 2009 | Unregistered CommenterOsher

Thanks for your reply Kurt. I understand reaching your natural "meant-to-be" weight as this has never been a problem for me. I suffered from anorexia in my teens (I'm a male) even though I was (naturally) very underweight to begin with. I have been diagnosed with clinical depression which I believe was the root cause of my eating disorder and now that I'm 40+ take SSRI's to stop myself commiting suicide (I've been hospitalised before). I actually feel good now but the thing is my natural bodyweight is low, slim etc. I can generally eat any type of food, high carb, low carb, high fat etc., without putting on weight and even pushed calories up to 5000+ when weight training (mostly with carbs and protein in the days before PaNu) but feel much better mood-wise and energy-level-wise on a PaNu diet. It's just I'm still thin and lean, which I know shouldn't be a problem as long as I'm healthy, so I weight train to build lean mass. I also like being strong for my weight which helps in practical terms and emergencies etc. Should I resolve myself to being the way I'm just meant to be? Guess I'm the guy who'd walk all day across the plains looking for animals to kill and then call up the big guys! :-)

August 28, 2009 | Unregistered Commenterwinalot

Also, whilst I've got you in a Q&A mood :-);

Lately (last 6 months) I've switched to a PaNu approach whereas before I was more Primal. So I've ditched fruits and nuts, hard cheese, replaced olive oil with lard (soon to be cream or tallow), increased fatty meat consumption and only vegetables/salad I eat is lettuce and broccoli etc.

I'm loving the PaNu/Paleo approach and have to admit I feel great!

But (there's always a but right!), I've noticed some gynecomastia building up under my left nipple (lumpy behind when squeezed, sore to touch etc.) with none in my right.

Is this a case of my hormone levels reacting to the greater saturated fat intake (increased testosterone aromatising to estrogen?) or is something else at work, such as too much O6, PUFA's etc.?

The only other time I suffered from gyno. is some years ago when I drank a lot of half-fat milk (litres of the stuff - what was I thinking!) to "bulk-up" but this went when I stopped (probably due to the hormones in store bought milk I thought).

I'm hoping it will level out but any thoughts greatly received.

August 28, 2009 | Unregistered Commenterwinalot

Osher, I agree the field is under-researched. There is a theory pushed by the government and industry that dominates "expert opinion" yet clearly does not measure up to the basic standards of scientific inquiry. Research that questions the dominant view does not get funded much.

As a scientist, I think about what is plausible, and look for evidence for or against a theory. Is it plausible that we are the only animals in the world who get sick on our natural wild diet? Is it a miracle or luck that we survived unhealthy all those millions of years hunting, to reach a modern era of great health with grains and lowfat processed food? Is there evidence that recent changes in the standard diet are the reason we are getting sicker?

I have not seen a large scale trial of people eating natural meat, plenty of fats and no grains or processed oils (I believe no such study exists). I have seen enough anthropology, both paleo and modern, to know that people who eat this way are healthier than most of us. So, besides reading existing research to glean some ideas, and hoping for a million-dollar paleo diet study to get funded, the only other way to learn more is to give it a try yourself.

For me there was enough doubt to justify an experiment on myself. Since increasing fat to 60-70% of my diet and eliminating grains and vegetable oil, I have got lighter (incidentally stronger and faster, with less exercise), raised HDL, lowered triglycerides. My average calorie intake has dropped spontaneously from about 3000 to 2500, although I enjoy eating very much and except for a fasting day a couple times a month, I never leave the table hungry.

August 28, 2009 | Unregistered Commenterjon w

@jon w
I agree with everything you say except the last paragraph. The moment you say "the only other way to learn more is to give it a try yourself", you drop the whole scientific base of your opinion. Since I started paleo diet my hair turned blond, my eyes blue, my triglyceride count is -20 and I pee HDL. What does it prove? Nothing. One person with great (Amazing!) results prove only the wishful thinking of that person, nothing more. Please, let's keep this discussion on a sound scientific ground (Which there is not enough of, but that's what we have to do with).

August 28, 2009 | Unregistered CommenterOsher


I agree. Let's all just go and live in a lab for a year.

On another note, I keep hearing that sex is enjoyable, even healthy. I, however, refuse to try this 'theory' out myself - thousands of years of anecdotal evidence means nothing to me. Until there is a sound body of peer-reviewed clinical studies to back it up, I'll remain a virgin. A happy, scientific virgin.


August 28, 2009 | Unregistered CommenterTaliesin


there is scientific evidence from dietary intervention studies showing spontaneous caloric intake reduction with low-carb diets. Almost all such studies let the low-carb group eat as much as they want while other groups are forced to limit their caloric intake. People in the low-carb group frequently reduce their average intake by up to 30% even when their access to food is unrestricted. This effect is much less pronouned in lean individuals. This discrepancy is probably mainly due to insulin resistance (nobody bothered to study). Studies measuring satiety (only a few of this type exist) consistently show higher subjective satiety rating with low-carb diets. Just turn to medline for references.

Also I disagree that nutrition is understudied. It is studied inefficiently (a lot of poorly conducted studies) and popularity plays too big a role in determining what to study.

August 28, 2009 | Unregistered CommenterAdrian

Kurt- how do you decipher the Randle cycle and the Krebs cycle in good calories, bad caloes?
if i undertsand correctly, low insulin keeps muscles from burning glucose and the liver does not give up the glucose. and isnt excess protein usually peed out?

" The Krebs cycle (triglyceride/fatty acid cycle) governs what occurs after a meal containing carbohydrates and the Randle cycle provides clues as to what is happening when we eat a high fat meal void of carbohydrates."

can you expand on these two a bit for understanding?

August 28, 2009 | Unregistered Commentermallory

@Adrian, Thank you for your answer, I will look for those research papers in pubmed, and see what I can find. I wonder how they measure satiety.

@Tal, Kid, get a life. The grown ups are talking about serious things here. Take Citalopram, have sex, whatever.

August 28, 2009 | Unregistered CommenterOsher


I know you asked Dr. Harris, but a few of things jumped out at me from your post:

1 - the Krebs cycle is NOT the same as the triglyceride/fatty acid cycle. Two completely different processes.

2 - I wouldn't say that the Kreb's cycle "governs what occurs after a meal"; IMO, it's more accurate to say that what you eat governs the Krebs cycle.

3- Low insulin prompts the liver to release its stored glucose. High insulin is a signal for the liver to store glucose.

4- The ammonia component of amino acids (protein) is pee'd out, but not the carbon skeleton. The carbon skeleton is retained and can be used as an energy source. But it is never "wasted" per se. Unless, of course, you have failing kidneys or some other pathology.

August 28, 2009 | Unregistered CommenterJoselyn


nothing fancy, they ask the participants. :)

August 28, 2009 | Unregistered CommenterAdrian


I see Joselyn has already responded. Here is a more detailed response.


August 28, 2009 | Registered CommenterKurt G. Harris MD


"How many calories is reasonable" is definitely a non-scientific, if not outright meaningless, question. For whom under what circumstances?

What does "reasonable" mean?

Maybe if you define your terms better and more scientifically, I'll go to the effort of providing you a link or two.

Or, you could expend some effort searching this site or even pubmed yourself.

The mechanisms of spontaneous caloric reduction are biologically plausible and there is plenty of supportive evidence that it happens, not least of which is that no one ever posts saying "I am following your recommendations and I've gained 20 pounds".

If you think my blog is not scientifcally grounded because I don't instantly provide all my references to you, you are free to find another more scientific blog to ask questions for free.

Also, be polite to the other posters.

August 28, 2009 | Registered CommenterKurt G. Harris MD

Testing out a diet (not in a weight-loss sense) is not only scientific, but the results of those tests are all that matters! Kurt could throw out this or that "theory" (which thankfully he does not), but what would it matter if the results were not there? Even if you follow the principles espoused by PaNu or Paleo eating more generally, you will likely have to tweak them slightly to fit your lifestyle, goals, and overall genetic make-up.

The standard "nutritionists" and "doctors" are the ones that have brainwashed us into thinking that a standard food pyramid works for everyone (it does not--in fact, it probably works for no one) and if you follow X and Y rules and eat Z calories you will be healthy. To the detriment of several billion people, this has turned out to be a disaster. What Kurt and others are doing is conducting real science, i.e. going from experiment and empirical evidence to principles, not the other way round. Eating the PaNu (or its cousin Paleo) way not only results in a healthy and desirable body weight / composition, it results in great OVERALL health. The SAD results in neither, and sham weight-loss diets, at the most, can only result in desirable body weight. The proof is in the pudding--and the pudding is you. So experiment on yourself and see if it works.

September 1, 2009 | Unregistered CommenterChad

Well scientific research is nice, but not everybody is willing to sit like a rock waiting for the powers that be, who have a definite conflict of interest that tends to inhibit if not outright prevent funding, to get around to making it official. Anybody can try it, and anybody can even armchair-logic out some of the basics given existing experience. Protein is filling. Fat is satiating. When I shifted my diet to <10% carbs, my calories dropped radically even though I was eating as much as I wanted, simply because eating mostly eggs and meat and some nuts and cheese had a completely different effect on my hunger, satiety, and insulin and other hormones, than living on mostly grain-based foods my life up till then had had. (Of course it took getting fully OFF grains to discover I'm gluten intolerant, so all the 'severe asthma', 'severe allergies', 'acid reflux', complexion issues and more vanished not long into that new eating plan. It's magic!) Oh yea, and a LOT of fat fell off.

I think there's still a lot more learning to be had especially with the very-morbidly obese, as there seem to be some specific metabolic differences (ref Jeff Friedman, geneticist @ Rockefeller U) going on there. Eating that way dropped a lot of weight off me and then stopped. Then I had reactive hypoglycemia effects -- but only for awhile; I upped my carb intake a bit and started going on and off lowcarb (not a good plan, just the way it happened) which oddly enough seemed to resolve that RH problem. I think it's possible that after losing ~150# my body just decided it had to put the brakes on for survival reasons for awhile regardless of all the other details; so that might resolve and continue with time, who knows.

Anyway, to a previous comment about whether there is science to show that reduction of carbs/grains in a diet will 'spontaneously reduce caloric intake', this is an easy no-brainer... just do it for a few months. I actually try to keep my calories UP, as I've proved to myself by careful tracking I don't lose an ounce if they are too low. Unless you live on bacon, butter and mayonnaise, it is damn difficult to eat <10% carbs and sufficient protein for a good sized body and still get >2500 calories.


September 11, 2009 | Unregistered CommenterPJ

Yep. PJ is right, except that is it exceedingly difficult to do on zero carb as well. After a big fatty meal (meat and fat only) I feel like I hate meat and all I want to do is nap. This is actually normal and a signal to you that you've hit a kind of saturation point. Time to rest and digest! I still never eat much more than 2500 Cals a day and the amount I eat seems to coincide with my activity level. I lost 25lbs eating this way. (Female, 5'6" 125lbs)

It should be noted that intermittent hyperphagia is probably quite natural on an extremely low carb diet (zero carb especially). You could look at it as a kind of survival mechanism to ward off starvation. Only in modern times has food been readily available and abundant. In paleo times your next big kill might come a week later, who knows. So pack on the fat while you can. It's still pretty hard to do and I suspect one can and will eat more the longer he goes without food (lower fat stores means more hunger signal). Most zero carbers tend towards 1 big meal a day. In the end, extremely low carb is the only way to maintain homeostasis.

September 14, 2009 | Unregistered CommenterMarnee

Hi Kurt, I've got a funny little question for you. While my scale weight hasn't changed much my body composition has changed with more lean muscle and less fat. However I am having trouble shifting the last bit which is in a strip across my belly button. The thing I have noticed is that the amount of fat seems to fluctuate throughout the day and night as estimated by pinching it. Is it possible that this fat is being used when needed and redeposited again via GNG. I can imagine fat being converted into glucose, insulin responding and the surplus being turned back into fat or could excess protein be doing it, I'm VLC/ZC. Possible or not? I want to lose this fat and am wondering if I should reduce protein and increase fat consumption.

October 13, 2009 | Unregistered CommenterAlan


Fat (other than the glycerol backbone of the TG) can't turn into glucose.

Diurnal variation in perceived body composition is much more likely to be due to hydration status than rapid cycling of fat stores.

More muscle and less fat is an expected salutary effect of VLC eating (lower insulin levels,etc.)that I have experienced and seen many times before. Other than that, I have no special insights into body sculpting.

October 13, 2009 | Unregistered CommenterKurt G. Harris MD

Dr. Harris,
Is there any difference between receiving your body's required daily glucose through dietary protein vs. dietary carbohydrate? What is the approximate glucose need for your your body when ketosis is providing most of the requirements for your brain, liver glycogen replacement, etc.?
In other words, is there any benefit or negatives of consuming 100g of protein and having the excess (let's say you need 60g/day so the excess is 40) convert to glucose (60 percent conversion rate= 24g of carbohydrate) when you are eating no carbohydrate vs. consuming the 24g of carbohydrate directly? If the latter, what are the best foods to obtain the carbohydrate through? Vegetables?

Also, (one could say consequently depending on the answer to the first question) are you familiar with the mTOR pathway and dietary protein's supposed effect on the pathway/aging?

Thank you,


November 12, 2009 | Unregistered Commenterklcarbaugh

I have 2 questions.

1) It's generally believed that dietary fat has virtually zero thermogenic effect. I wonder whether the thermogenic effect varies with a) chain length & degree of saturation of the FAs in the fat (e.g. the SCFAs in butter & coconut oil being thermogenic & LCFAs not) and b) the subjects' insulin sensitivity. This would explain why some people lose loads of weight on HFLC diets and others gain.

2) It's generally believed that serum insulin has to increase for cells to up-take glucose for the production of glycerol-3-phosphate. I have a theory that this isn't necessary.


Regarding #1, could be - seem like angels on the head of a pin - I don't look at fatty acids as pharmacologic agents other than in the case of MCTs and neurologic disease so can't see why it's that important - eat quality animal fats and the ratios of different fatty acids are what they are. Varying insulin sensitivity at equicaloric intakes should have an effect on weight loss of course.


email me off blog (through about me) and tell me what you are getting at - I've seen you mention Taubes is "wrong" about G6P elsewhere, but I'm not clear what your argument is so I can't respond to it. What do you mean by increase -relative to what? transiently? permanently? AUC or spot measurement? Of course lipolysis and lipogenesis are always occurring at the same time at varying rates so it is net fat loss or gain we should be concerned about.

January 6, 2010 | Unregistered CommenterNige

Emailed. Hope you got it. Did you click the link in 2) ?


Yes I am guessing you want me to read the comments

January 6, 2010 | Unregistered CommenterNige

You guess right. However, I've now "gone public" with my theory. It's at:-
I have a theory.

January 7, 2010 | Unregistered CommenterNige
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