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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Raw Paleo and Zero Carb - right for the wrong reasons

Since the site seems to be attracting some interest from the raw crowd, I'm going to tell you what I think of the raw idea.

Much of the raw paleo discussion emphasizes the raw over the paleo. Raw modern fruit loaded with fructose is more paleo than lightly cooked meat? Not a chance.

Whether a food has been subjected to heat is more important than the macronutrients, micronutrients and antinutrients in the food? That seems absurd as an organizing principle.

We have not had time to metabolically adapt to cooking? Whether we have been eating cooked food for merely 250,000 years or millions as Richard Wrangham claims, there has been plenty of time for us to adapt to cooking. I don't find any of the arguments against cooked food convincing.

Where does the raw is better idea even come from? It seems based on analogical or simple syllogistic reasoning rather than science. It takes technology to cook, so we must be better off without cooking because other animals can't cook? There is very good evidence humans evolved in a divergent fashion from other primates. As gorillas went in the direction of vegetarianism, hominids since H. Habilis over 2 M years ago evolved to eating other animals. I believe the caloric density and efficiency of becoming predators and exploiting the fat stores of other animals allowed developmental energy to be devoted to brain growth, which in a virtuous cycle, allowed development of social organization and technology including organized hunting coordinated with gathering and cooking technology. This social and technological evolution combined with carnivory fed back into further brain growth in a positive feedback loop over (at least) hundreds of thousands of years culminating in H Sapiens.

But let's say I am wrong and cooking is only 50,000 years old. Even if that were so, where is the evidence in the present that we are not adapted to it? Unlike the case with wheat, linoleic acid and fructose, I've seen no medical evidence cooking is bad. The PaNu method is informed by science. To posit evolutionary discordance requires harm in the present, not just lack of evidence we did it back in the day.

How about refrigeration? That is less than 100 years old. I wonder how many raw paleo folks refrigerate their meat? Shall we shun refrigerators because only fresh or rotten meat is truly "paleolithic"? I say only if there is some biologically plausible medical reason to suspect refrigeration (or central heat, or laptop computers, etc..) is bad for us.

PaNu is about metabolism, not food re-enactment. Simple analogical reasoning without attempts at falsification can easily lead to the same silly emotional reasoning used by vegans like Ingrid Newkirk (a rat is a pig is a dog is a boy...)

Raw paleo is based on a completely unsupported dogma against cooking that has zero basis in biochemistry, medical science or paleoanthropology. It is based on weak analogical argument only. Positing that the core dogma is that everything should be raw and then arguing over a spectrum from raw veganism to 100% meat ignores the most fundamental elements of metabolism. Saying that butter or cream are not "paleo" because they were not consumed way back when, when these animal based sources are nearly pure animal fat is just nonsensical.

The good news is raw paleo seems to exclude wheat, non-fruit sugar and excess plant oils. I like where most of raw paleo ends up, I just don't like how they get there.

As far as the "zero carb" thing, I have the same concerns. Saying all carbs are bad, and we cannot tolerate them at all is just another unsupported dogma. Saying we don't need carbs vs making a fetish of totally avoiding them can lead you to very different places, one of which is the reasonable accusation of being cultish and unscientific - this impedes spreading the message and hence makes it harder to help non-fanatics with their health. My own diet is nearly zero carb some days but I have never claimed that that is is better than 10 or even 20% carbs. I am not saying it is not, I just don't have evidence that it is.

I eat my meat so rare it is almost raw and I eat sashimi and tuna completely raw. But not because of raw dogma, I just like it that way. I eat no potatoes or white rice or yams because I am sensitive to starch, not because I have unequivocal evidence they are bad in small quantities. I eat a VLC nearly carnivorous diet. The most important elements of this are no wheat or other grains, zero plant oils and very low fructose. Whether the carb level is 2% or 10% or even 20% with preservation of these more important parameters, I have not seen evidence there is a difference.

PaNu is often conjectural, but will always be based on science and I am constantly looking for evidence I might be wrong.

PaNu is proscriptive (don't eat that food!) because the way to the EM2 is to avoid the neolithic agents of wheat, linoleic acid and fructose, not through duplicating a particular dietary composition from the paleolithic period - there was too much variety to even do that, and much of what I read about what paleo man ate is pure conjecture if not paleofantasy.

I am fairly confident about what paleo man did not eat, however, and that makes our task much easier.

I welcome zero carbers and raw meat carnivores - you are way healthier than those on the SAD, but your will is more durable if backed by a resilient science instead of a rigid and brittle faith.

Reader Comments (52)

Well said Kurt!

August 16, 2009 | Unregistered CommenterGrok

I like this approach. "I am fairly confident about what paleo man did not eat..."

Good way to think about it.


August 16, 2009 | Unregistered CommenterTony K

Reasonably well put. Raw paleo (for the sake of raw) is ludicrous and paleo man likely ate some carbs on occasion (though probably not every day).

However you can't just dump the line:
"Saying that butter or cream are not "paleo" because they were not consumed way back when, when these animal based sources are nearly pure animal fat is just nonsensical."
... into the middle of this argument and treat it the same way.

Dairy is not paleo, as paleo man did not consume it. All dairy products still contain the milk proteins and they have been linked to autoimmune diseases. MS is likely a direct result of dairy consumption. Many asthmatics have direct diary caused asthma.

You can't just ignore the basis of the paleo diet for butter or cream just because you can't see anything wrong with them or want to eat them.

August 16, 2009 | Unregistered CommenterTarlach


"Dairy is not paleo as paleo man did not consume it."

I think you are not hearing what I am saying. Once again, it does not matter that they did not consume it.

If you have an allergy to something, don't eat it. Some people are allergic to seafood. Seafood is historically paleo. Shall we eat based on health effects or based on historical precedent?

How about fructose? Plenty of historical precedence for eating fructose, but do you disagree that the less of it you eat the better? If so, you have not read much about fructose. Fructose is historically paleo and is metabolic poison. Do you think it causes more or less trouble than butter or cream? If less, where is your evidence?

As far as millk, are you saying the Masai are not really healthy on cow's milk? How about traditional swiss as described by Weston Price?

Where casein in milk is a concern, as it may be theoretically, is in the context of wheat consumption or some other cause of leaky gut. In such cases, any protein, including those from otherwise harmless commensal organisms in the gut, can be the trigger for an autoimmune reaction. What is the cause, then, the 100 varieties of protein that may leak through, or whatever caused the leaky gut?

Milk and bacteria may associate with immune diseases the way that ragweed pollen is associate with allergic rhinitis. Are the hundreds of potential foreign proteins that trigger sneezing in atopic individuals then each "causes" of allergic rhinitis? Of course not.

How about some evidence that those without an allergy to milk are damaged by it when on a wheat free diet?

I don't care if they ate it or not. I care if there is convincing scientific evidence that the average person on a wheat free diet has to avoid it. I have not seen that evidence yet.

Those lactose intolerant (sometimes also due to wheat or silent celiac disease) should avoid milk the way those with shellfish allergy should avoid prawns.

If you fear butter and cream don't eat them. Butter and cream are fine for most people. If you have good evidence (not just speculation) they are not, let me know what it is.

Your statement that "MS is likely a direct result of dairy consumption" is frankly speculation and in my opinion there are several other factors more important than milk consumption - the evidence indicting milk is observational, like the evidence indicting saturated fat that we all agree is confounded by other factors.

I have read plenty of literature about both wheat and casein and I find vastly more evidence indicting the former.

If you have something other than anecdotal or observational evidence, let me know. If the evidence rises to the level of that indicting wheat, I will recommend against all dairy the way I do gluten grains.

August 16, 2009 | Unregistered CommenterKGH


August 17, 2009 | Unregistered CommenterTarlach

Why do you have the tag line "paleolithic nutrition - duplicating the evolutionary metabolic milieu" if you do not care what paleo man ate?

You say that health problems are caused by changes "in the way we eat and live that have only occurred over the past 10,000 years".

This is how long we have consumed dairy for...

August 17, 2009 | Unregistered CommenterTarlach


I interpret diseases in the present in the light of what we know about metabolism and in light of what we know about evolution. It is simplistic to stamp foods "paleo" or "non-paleo" and assume that equates to health.

I state explicitly that it is the paleolithic internal hormonal and metabolic milieu I believe is healthy, not a checklist of particular foods eaten. Why is that hard to understand? It is the paleolithic metabolism, not the particular foods.

Do you eat Mammoth and grubs? Do you fast for several days at a time to mimic the experience of paleo man? Do you practice infanticide because paleo man did this? Do you shun central heating so that you burn more calories at night to keep your insulin levels low? Do you think we should elevate our homicide rate to 25% so that we can have a social environment similar to paleo man?

What people ate way back can be a a clue to what is wrong now, never an endorsement . It is a non sequiter that anything not eaten is bad and anything eaten is OK.

If you want to practice a cult of food re-enactment and fool yourself that fructose is good because paleo man ate honey when he could, and clarified butter which is nothing but animal fat is bad because paleo man did not eat it, go ahead.

How can you possibly eat beef? Paleo man ate Aurochs, not the modern beef cattle which have been artificially selected over thousands of years and which has proteins and fatty acid ratios that are almost certainly different from what was present in the paleolithic period.

Should we avoid Vitamin D and cod liver oil even though their benefits are well established? Those were not available to paleo man, were they?

Start with medical science and then look at paleoanthropology. Then you can have a science instead of a fetishistic cult that is accidently healthy.

August 17, 2009 | Registered CommenterKurt G. Harris MD

Kurt, I like your comments here. Lately I end up describing what I do as 'paleo informed'. Food re-enactment is another helpful term. Not saying I won't eat bugs or old roadkill, but that I'll have to be pretty hungry to do it, and I won't do it out of any sense of moral superiority. Maybe I need to become more OCD.



August 17, 2009 | Unregistered CommenterCraig

Well timed posted! Your blog is quickly becoming a must read for me which also includes Stephan's and Art's.

I'm tired of people using dogma to make their nutritional choices for them. I'm confident you'd be willing to change your views if the science demanded it.

I'm pretty much with you 100% in your recommendation against too much fructose, wheat, and vegetable oils.

Where I'm not so convinced however is carbohydrates vs fats. When I've looked at literature, I've seen many studies that show avg insulin levels are low even when consuming carbohydrates if weight is kept low. People also seem to forget that protein can also stimulate insulin independently of carbohydrate.

I feel the recommendation to switch carbohydrates with saturated fats is not clear cut yet. Without a doubt, you don't want to eat a heavy grain diet loaded with phytic acid and other anti-nutritional factors. But when you consider foods such as sweet potatoes, potatoes, or non-gluten grains that have been soaked and fermented, you have a pretty clean food source.

I'm worried that a very high fat diet is going to increase the number of mitochondria (which normally is considered a good thing)- and therefore, increase the byproducts of fatty acid oxidation. I've also seen studies on rats where when a higher percentage of fuel is burned through uncoupling proteins-- lifespan is increased (probably through the fact that there was less beta oxidation going on, and therefore, less byproducts).

Polyunsaturated fats also increased uncoupling proteins at the expense of beta oxidation-- is it possible that a diet higher than you are recommending in polyunsaturates (albeit balanced 3/6s) might allow for more glycation in the body, but lead to a greater longevity via a slowdown of beta oxidation?

I for one believe there is a difference between a type of diet that produces the most robust possible health for the moment vs the best type of diet for longevity. Higher protein, high fat, lower carb diets without a double produce the most robust human possible. I just have this feeling though that if you want to get a squeeze a couple more years out-- with a little less robust health, you'll need to go lower protein, moderate fat, moderate carb. But that is my viewpoint.

As a side note-- antioxidants and plant-like compounds as we know them-- are actually a negative to the most robust health possible if you think of them as slowing down processes that make us stronger. (This is assuming you are in a perfect environment) But i'm willing to eat foods that have them because they slow reactions and help me to life just a little bit longer-- and to deal with toxins in the environment that man has never had to deal with before

August 17, 2009 | Unregistered CommenterAaron



Your speculations are interesting -I have read your comments on other blogs.

I can only say that it may be that higher levels of carbs than what I eat may be tolerable, but I have yet to have anyone show me any evidence that they it would in any way be beneficial.

As far as Linoleic acid, whatever comes along for the ride with my animals fats is fine. I've seen no evidence that going above that is of any benefit and plenty of evidence that more LA is worse than what I get get now.

Indeed, I can't think of a biologically plausible reason why more LA would be healthier.

I think processing fatty acids for energy is healthier (cleaner) than glycogenolysis and burning glucose.

But then, you would have to think that to eat 70% of calories from animal fats, I guess.

August 17, 2009 | Unregistered CommenterKurt G. Harris MD

Want to know who puzzles me? Udo Erasmus-- by all accounts, this man should show all the signs of accelerated aging. He consumes a decent amount of polyunsaturates-- albeit, it a 2:1 omega 3 to 6 ratio-- but he's been doing this for years! Not to mention the fact that he says he was poisoned-- shouldn't the polyunsaturates be causing havoc on his liver-- or aging his skin? I know this is only one man -- and he does have financial interests in his oil-- but most of his other logic seem spot on in terms of reducing fructose, eating whole foods, etc. I wouldn't just like to dismiss the studies he's done with athletes showing improved endurance and recovery.

In fact, I'm not sure if your familiar with Seth Roberts (shangri la diet fame) -- but even he on his blog has had many testimonials in terms of faster wound healing (and gum healing) with adding flax seed oil-- now, by no means am I saying flaxseed oil is healthy-- but it's our job to determine why the wound healing is faster-- or the fact that bruising is less. The reason why I'm even mentioning this is because I've seen testimonials on others sites that talk of slower wound healing and and greater bruising on an anti-inflammatory diets, and diets low in polyunsaturates (even ray peat, who is against polyunsaturates of any kind talks of slower wound healing on a low polyunsaturated diet). Art from cooling inflammation even had a similar conversation on the comments section of his blog. Talking about how it's possible that tissue healing is slower if there is not excessive inflammation (like on the standard american diet).

We need to figure out the benefits and negatives of certain eating patterns-- Even Art, like yourself, dismisses plant-like compounds as having too much effect because he expounds that the main effect they have is to raise uric acid -- and therefore, indirectly raise the bodies anti-oxidant capacity (so no need to eat too many veggies or fruit there). And even you have dismissed any major danger from the consumption of glycated proteins that would be the result of cooking meat. Maybe we don' t have much to fear in terms of polyunsaturates as long as we keep omega 3/6 in balance- and don't overeat-- in fact, maybe we should eat a little more if they are shown to increase uncoupling proteins and slow down beta oxidation? The question is: at what level is optimal-- maybe to the point of where any excess of polyunsaturates would increase inflammation even when balance-- where this lies, I'm not sure. 2% 3% 4%?

So the question is: how much do studies like this matter for humans?


Is it the case that even if you have balance omega 3/6 fats-- that after a certain percentage of polyunsaturates -- that you will have increased inflammation? Does the increase in inflammation matter if you increase uncoupling proteins at the expense of beta oxidation?

Is curbing inflammation the #1 thing we should be worrying about?

I even worry about messing up my HPA axis on a high fat diet without carbs because I feel that my dopamine and norepinephrine almost certainly rise on the diet. 6 weeks on a low carb diet did nothing to calm me down (in terms of adjusting). I'm sure others have felt like this before. My adrenals were always stressed out.

As long as your are getting most of your vitamins from real foods-- and your minimal mineral requirements-- you can get your calories from carbs as long as they don't tag they aren't rich in phytic acid or tons of antinutrients (maybe this is where soaking or fermented them comes in.)

I guess I have more to fear from large increases in beta oxidation by the adoption of a high fat low carb diet-- then I do of increasing insulin a couple of times a day for the carbs i consume-- If I maintain a low weight-- the insulin response is just not that large (especially if i don't consume the carbs with fat). And once again, protein foods do cause increases in insulin!!

August 17, 2009 | Unregistered CommenterAaron


You say, "I guess I have more to fear from large increases in beta oxidation by the adoption of a high fat low carb diet-- then I do of increasing insulin a couple of times a day for the carbs i consume"

I would say my reading of the clinical literature is that you do indeed have much more to fear from raising your insulin levels than from the entirely theoretical concern you seem to have about "beta oxidation"

I think if you focus on theoretical biochemistry without the vast clinical knowledge we have of metabolism you run the risk of convincing yourself of something that might turn out to be a dangerous fantasy.

I'm not convinced more carbs or more linoleic acid might be healthier. In fact, I strongly disagree.

As far as saturated fats being generally healthier than carbs, to me it is indeed clear-cut that sat fats are healthier.

Also, I am not sure what you mean by my dismissing "plant compounds" - I don't' remember saying anything about it as I am not sure what "plant compounds" you are talking about. Lack of comment indicates neither approval or dismissal.

August 17, 2009 | Unregistered CommenterKurt G. Harris MD

I'm sorry I did not exactly clarify what i was trying to say about "plant compounds"

First off, I assume that you wouldn't be eating veggies for the fiber-- secondly, if you ate veggies at all, you would be eating them for the vitamins and minerals contained in them-- i also would figure you are minimally interested in the plant like compounds-- such as isocyanates that come with a food like broccoli-- and that you are wary of anti-nutrients that are present in many veggies-- so overall, I'd figure that you wouldn't really care to eat veggies if you could get similar nutrition from foods that don't have anti-nutrients-- such as animal products- and I correct in this deduction?

Am i correct in saying that you really wouldn't care for the anti-inflammatory of certain foods-- like turmeric, tea, or ginger, if you could set the body on the right path in the first place by eating the diet plan you lay out-- basically making the consumption of veggies optional? I'm open to the idea that you don't need these plant compounds if you give the body everything it needs-- without causing excess inflammation in the process- which by your words would be to consume small amounts of polys, have no sugar, no wheat, and mostly fats-- to create the optimal milieu. Is this also correct?

I think we are in alignment on most issues. I think the only possible senario that scares me the most is the super low carb one. I just don't know how consuming 30 or less carbs a day really adds to the health equation- vs someone who consumes 50-100 carbs a day and stays out of ketosis. Honestly, I'm starting to feel that whatever keeps the body minimally out of ketosis is going to be optimal because it will minimize insulin-- and keep protein from turning over too much-- which can happen on a 0 carb diet-- a little bit of carbs will also aid in the production of serotonin and other stress relieving hormones which can clam the stress axis down-- which i feel is a good thing.

I understand your concern for theoretical biochemistry. It is important to go on what we know now-- rather than just assume things that could later be proved false-- However, I do believe that there is way more than insulin to blame in the aging process-- I also believe growth hormone and IGF-1 to be implicated in the process of aging(also keeping and eye on the byproducts of fat oxidation). It's possible that having too many growth factors accelerates aging by some unknown factor we do not know. We need to keep our eyes open to these things. Things that turn on the repair genes do seem to do the opposite of those that turn on growth-- these are things we know.

August 18, 2009 | Unregistered CommenterAaron


what are these "byproducts of beta-oxidation" you keep talking about? Names of these compounds would be nice. I've already answered your concerns if you mean ROS or other radicals - see WholeHealthSource blog, The Diet-Heart Hypothesis: Subdividing Lipoproteins, last comment. Still even given the differences in NADH/FADH2 ratio I don't think there is a tangible difference between aerobic glucose oxidation and beta-oxidation in terms of ROS/radical generation save for PUFAs.

In ketosis protein turnover is not high as far as I know. What people seem to forget is that the minimum 30-50g of glucose per day doesn't have to come from protein. RBCs which metabolize most of this glucose do not do so aerobically and the resulting lactate is recycled in the liver back to glucose without the need of additional gluconeogenic precursors. This means the amount of glucose produced from protein per day during ketosis is likely below 10g.

Why should staying out of ketosis minimize insulin? Have you seen some studies showing ketosis increases total insulin output (amount of insulin secreted per day) compared to a non-ketogenic diet? Ketone bodies do not stimulate insulin secretion alone although they do potentiate it in response to some other weak insulin secretagogues.

The carbs = serotonin production theory is probably not entirely true. I cannot locate the paper now but I've read a study a few months ago which used radiolabeled tryptophan and showed there were no differences between a high-carb and a low-carb meal in stimulating serotonin production and not only that - the difference was statistically nonsignificant compared to the baseline aka feeding did not change the serotonin level at all. The feelings typically associated with a high-carb meal are probably due to insulin's effects on the brain which may or may not involve the 5-HT receptor.

August 18, 2009 | Unregistered CommenterAdrian

Thanks Adrian

Aaron - let's try to stay closer to the blog post topic

August 18, 2009 | Unregistered CommenterKurt G. Harris MD

Hey Kurt,

You're blog is great and I'm really enjoying your posts.

While I've learned a lot in my zero carb journey, I wouldn't go as far to say that controlling hunger through carbohydrate elimination is a dogma. If the body produces too much insulin at a 10% carbohydrate intake (induces cravings), the next logical step should be to restrict that amount even more.

Keep up the great work.


August 18, 2009 | Unregistered CommenterDanny Roddy

Hey Danny

Thank You

I've enjoyed your blog, too. As I've said repeatedly, my own diet is a bit like Stefansson with butter, cream and eggs.

For the record, I doubt if there are insulin benefits of going below 10% carbs and definitely not if you are eating more than 15% or so protein. An optimal diet like ratio of 80 fat 10 pro and 10 carbs will optimize insulin better than 60 fat and 40 protein.

I don't want to be seen as criticizing ZC, I do not think it is unhealthy even if its not "optimal". I love how anti-mainstream the all meat approach is. I am just wary of invented dogmas. One of my goals is to gain ground for paleonutrion among academics and MDs - how we make our arguments can thus be as important as what we are arguing for.

We share our disdain for fruit and vegetable worship, and that is quite scientifically sound.

Semper Fi

PS I have been trying to learn guitar over the past 6 months at age 48!

August 18, 2009 | Registered CommenterKurt G. Harris MD

I reviewed Stefansson's accounts on satiety with varying ratios of pemmican (70/30, 80/20, and 60/40), since then I've switched back to an 80/20 ratio with a decrease in hunger and what seems to be an increase in mood and energy. My "reasoning" (self diagnosis) for switching to a 60/40 diet was dubious at best...

You have a wonderful way of putting things Kurt, you're very well spoken. I'm sure that will translate into some face melting guitar riffs.

August 18, 2009 | Unregistered CommenterDanny Roddy

What about tryptophan, taurine and other heat labile stuff? Isn't steak tartare a better source of these than cooked beef?

August 18, 2009 | Unregistered CommenterMike Aliyah


Cooking denatures proteins in advance of their arrival to your stomach, and by breaking down the collagen generally increases bioavailability of the amino acids hydrolysed and liberated from the meat.

I suppose one could reduce all the amino acids to elemental C N etc. by reducing the meat to ash, but that is not how I cook. Do you think light cooking destroys amino acids? I don't.

Do you have a reference describing clinical amino acid deficiency due to cooking meat?

Why are you concerned about Taurine? Are you a cat?

August 18, 2009 | Unregistered CommenterKurt G. Harris MD

Kurt Harris is reading our forum http://www.rawpaleoforum.com
Maybe he's a member.
Keep reading Kurt.
I personally am on raw paleo diet because it works for me, it gave me a 2nd life, a better life than the previous one.
I just stumbled onto this diet and did not know it was named this way.
Self experimentation rules!

August 18, 2009 | Unregistered CommenterEdwin Casimero


I've seen the forum but not read any but a handful of posts.

August 18, 2009 | Registered CommenterKurt G. Harris MD

so carcinogens, AGEs, nutrients and enzymes being heat sensitive are all myths according to you?

August 18, 2009 | Unregistered CommenterPete


There are a number of nutrients that humans supposedly can synthesize such as DHA from ALA precursor, Vitamin A from beta carotene precursor etc. If this capability is limited, it would be preferable to skip the synthesis step by getting these things preformed from animate sources. I just recall reading that the human ability to synthesize taurine is limited. Perhaps it isn't, but I like steak tartare well enough to give myself some insurance.

August 18, 2009 | Unregistered CommenterMike Aliyah


I presume you are asking if I believe it to be true that cooking results in compounds that actually cause cancer in humans? (not just theoretically, but actually)

No, I do not. Do you have actual clinical evidence for this?

Do I believe that cooking lipids and sugars can create ALEs and AGEs? Yes.

Do I believe that consuming ALEs and AGEs is an important cause of cancer or oxidative stress inside our bodies, more important than the hormonal milieu and metabolic processes inside our bodies?


Do I believe nutrients can be destroyed by enough heat (overcooking). Of course they can. Do I believe that light cooking substantially degrades the nutritive value of food? No. It actually improves the bioavailability and digestive efficiency on a net basis.

Do I believe enzymes can be denatured by heat? Well, any protein can. What do you think happens to every protein (including enzymes, which are proteins) when you eat them? The stomach uses an acid environment (pH 2.0) and Pepsin to first denature and then hydrolyze proteins into their constituent amino acids in the stomach. What possible difference would it make if you denatured them with heat first?

Are you saying there are essential enzymes in meat we cannot live without - some kind of enzymatic vitamins?

I was under the impression that some raw foodists think cooking is bad but eating rotten meat is good. What do you think is happening to the proteins and enzymes as the meat gets stinky? How about denatured proteins and degredation of the meat by bacteria?

The whole raw food thing strikes me as just ignoring what goes on during digestion.

One last try. You are aware that that cosmic rays bombard the earth constantly. You are aware that ionizing radiation can initiate cancer in large enough doses, right? You are aware that a normal healthy human has evolved cellular mechanisms that constantly repair the occasional bits of damaged DNA that result when a cosmic ray strikes a strand of your DNA. You know that most cancer is caused by failure of the body to keep up with the damage or failure of the NK cells to stop the abnormal cells from proliferating. You are aware that Insulin and IGF and the 6:3 ratio and vitamin D are all likely much more important to whether you get cancer than if you take a high altitude airplane flight or live in Denver.

So do you advise we all walk around with lead suits to avoid cosmic rays?

That is what you are doing when you worry about eating Maillard compounds or minute quantities of artificial pesticides instead of focusing on the internal hormonal and metabolic milieu of our bodies.

I find it ironic that raw foodists who eat meat use the same kind of specious reasoning that the anti-meat vegans use to indict meat in general - cooked meat causes cancer, etc.

Mike - humans can synthesize taurine and use it to make bile salts - I have every confidence that you will not become taurine deficient on a high meat diet, cooked or not. As I said, I eat my meat closer to raw than well done and partly because I recognize that overcooking is not good. It just seems crazy to be fearful of cooked meat as a dogma. There is no clinical evidence of harm from cooking any food - I've never seen it and I do not think it is biologically plausible.

August 18, 2009 | Unregistered CommenterKurt G. Harris MD


Just now happened across this paragraph in a book review at this site:


"Schmid notes that in every culture studied by Price, certain foods were eaten raw--whether milk, cheese, organ meats, muscle meats or fish. He describes Pottenger's experiments with cats, in which cats given cooked foods developed the same diseases as humans eating processed foods. Schmid's points regarding raw animal foods, especially raw milk, are well taken, but it should be noted that all of the cultures Price studied built fires and cooked some of their food--even in cultures where fires were not needed for warmth. Grains, tubers and plant foods were usually fermented and/or cooked. In fact, in a letter written to his nieces and nephews, Price recommended that most vegetables be cooked, because for humans, cooking made it easier to absorb minerals from these categories of food."

August 18, 2009 | Unregistered CommenterMike Aliyah

I agree that going raw just because cooking requires technology is ridiculous. I also don't think eating everything raw is necessarily the healthiest thing. We are probably quite well adapted to cooking.

I'd like to know your opinion on glycation, though -- I take it you're not afraid of Advanced Glycation End-Products (AGEs) from cooking? I know endogenous AGEs are probably the bigger concern, but I wouldn't rule out exogenous AGEs either.

I think a medium rare steak is probably a smaller risk than consuming raw meat, even though it has AGEs, but I still take benfothiamine and drink yerba mate to reduce glycation.

Nice blog!


August 19, 2009 | Unregistered CommenterJLL


You just made my point for me perfectly. WAP found no cultures that make a taboo of cooking in general.

Can you point me to any evidence that there are or were HGs that religiously avoided all cooking?

I am not arguing against raw, I am arguing against the dogma that cooking per se is unheatlhy.

I don't cook my cheese before I eat it. I eat raw tomatoes and onions and sometimes mushrooms. My meat is so rare it is allmost raw.

The idea that I am damaging my health by making chili in a pot is ridiculous, but that is what the raw dogma would say.

August 19, 2009 | Unregistered CommenterKurt G. Harris MD


I am well aware of the theory on ingested AGEs and have read several papers about AGEs and ALEs created by cooking.

I never say never, but so far I am not convinced that eating AGEs is a major source of disease. I am not saying you could not make it significant, by say glazing hamburgers with sugar and then burning them beyond recognition on the grill, then eating nothing but that. But who does that? Not even grill fanatics.

In a previous post on this thread, I used the analogy of wearing a lead suit to ward off cosmic rays. It is conceivable that we could take vitamin D and wear lead suits, but it is not conceivable that such an awkward maneuver would prevent more disease than the much more practical and very important dietary maneuvers I usually discuss on this blog.

The idea that there is a hormetic benefit to natural radiation is a fairly mainstream idea. Eating AGEs or even minimal internal oxidative stress may turn out to be hormetic as well. I don't know.

August 19, 2009 | Unregistered CommenterKurt G. Harris MD

I am "afraid" of the following:

gluten grains, excess linoleic acid and fructose

I could become afraid of other agents if I saw evidence that they were harmful.

I try not to fear things based on just armchair hypothesizing as that wastes valuable energy I could spend fearing the stuff that is more likely to kill me.

August 19, 2009 | Registered CommenterKurt G. Harris MD


All I said was these cultures (per Weston Price) all eat *part* of their animal source food raw. Per Sally Fallon, and I have checked this wtih google, B12 is heat sensitive and damaged by pasteurization.

Which is what I do - part of the animal source food I eat raw, some of the cheeses I eat, not all, are from raw milk.

August 19, 2009 | Unregistered CommenterMike Aliyah


No disagreement.

Please understand I am not claiming all food should be cooked, I am merely disagreeing with those who I understand to be saying that you will come to harm if any of your food is cooked.

Nobody cooks everything. If raw foodism is saying that "some of your food should not be cooked so much', then no problem.

I am not telling anyone else to cook. I am simply taking issue with any who claim it is unhealthy to cook at all.

August 19, 2009 | Registered CommenterKurt G. Harris MD


You seem to be arguing that *any* raw meat is unhealthy. The USDA says sticking meat in the freezer for 14 days will kill any parasites. As far as the bacteria go, I figure my immune system is strong enough to take my chances.

I seldom eat pork or poultry, but when I do I cook them. Its just fish (sometimes) and beef (usually) I eat raw.

August 19, 2009 | Unregistered CommenterMike Aliyah


If you misquote me again, I reserve the right to delete your post.

I have said it repeatedly on this blog and will say it only one more time. If you are confident of the source, that it was not processed with e coli contaminated equipment, etc., I see no problem with eating meat raw. I have done so myself.

Same goes for raw dairy if you are tolerant of it and confident of the source.

For the last time, I am not saying anything has to be cooked.

I have not once, ever, anywhere said raw foodists should start cooking everything they eat

I am only objecting to the argument that it is unhealthy or dangerous to cook any of your food.

Is that finally clear enough, or have I failed once again?

August 19, 2009 | Registered CommenterKurt G. Harris MD

Kurt, would we have to fear acrylamides from fried tubers? Or, would we have more to fear from the sugar itself contained in the tuber than what happens to the heated cooking oil (which would be olive oil, coconut oil, butter) or the acrylamides?

August 19, 2009 | Unregistered CommenterAaron


Let's say you have a french fry from McDonalds

In order of danger it contains:

1) some industrial oil high in O-6s

2) starches which there is no real need for but in small amounts are fine


42) acrilamides

I am of course being flippant.

But seriously, my path is to identify dangerous stuff and tell you why you should not eat it.

As soon as I become convinced there is a new neolithic agent, in addition to wheat, linoleic acid and fructose, I guarantee I will post a well referenced article describing the dangers.

There are obviously thousands of theoretical candidates for harmful substances. I want my site to be an oasis of reasoned opinion backed by hard science. It takes more than mere suspicion, or even an in vitro or rat experiment to indict a food or recommend a supplement. If you want to get confused and frightened regularly, you always have MSN and the new york times.

My not agreeing that something is dangerous does not guarantee something is safe. In my further research, I might decide to start worrying about something I am not concerned about now. The instant I am concerned by a new threat, it will be posted on this blog.

I promise.

August 19, 2009 | Unregistered CommenterKurt G. Harris MD

Thanks for your reply-- I can easily get off course on your site because your insight leads to many questions.

You answered how I thought you would

I love you fry up a little bit of sweet potatoes now and then in oil-- just wanted to make sure I was probably right in not worrying too much about the heated olive oil/butter/acrilamides and focusing more on making sure overall carbs/fructose/polyunsaturates are kept low.

August 19, 2009 | Unregistered CommenterAaron


You are welcome.

I am not one of those who thinks olive oil is magic. It is probably healthier (definitely cheaper) to cook with butter or beef fat.

August 19, 2009 | Unregistered CommenterKurt G. Harris MD

Hi Kurt,

I became the family healer after I cured myself and learned healing principles. It just so happens that when the chips are down, when people are truly sick, many times 100% raw paleo food is the most powerful answer.

August 20, 2009 | Unregistered CommenterEdwin Casimero

I have no doubt that the diet you recommend would be adequate for life and lead to good health - if I had started eating that way earlier in life. In fact, in my early 20's, I got worried about a slight weight gain and started reading about nutrition. After reading some stuff like Adele Davis and the book Sugar Blues, I decided to drop white flour and sugar from my diet.

I didn't have the first clue about carbs, gluten or PUFA's. Every meal was pretty much a piece of meat, brown rice or potato and some kind of vegetables. I ate very little bread because I couldn't find any whole wheat bread without sugar. I trimmed up and felt fantastic.

Unfortunately, the diet fell apart when I discovered Fritos and potato chips had no sugar (like I said - I was clueless). A few years later, I gained a bunch of weight and spent the next almost twenty years fat and miserable.

When I was about 40, I discovered low carb and I I then went completely gluten free the day I turned 42. I was doing low carb, I was gluten free and I avoided PUFA's because I didn't think they were healthy. Despite all of that, I couldn't budge the weight.

I turned 45 this year and was still holding at about 200 pounds (30 pounds overweight - I'm a 5'11" male). Last April, I was researching elimination diets while trying to trace down something that was still bothering me and I stumbled on to the Zeroing In On Health zero carb forum. After reading the reference materials and looking through the posts, I decided I would give it three months and see what happened.

The first two months went great. I dropped from 200 lbs to about 184. I was eating pretty much zero carb but was occasionally adding a few mushrooms to my steaks or having a few bites of broccoli when the family had some. I would also occasionally have 6 or 7 macadamia nuts after dinner. I figured that even with these things, I was still under 10 grams of carbs a day. It didn't seem to affect my weight loss at first.

After a couple of months of this, I stalled out around 184 lbs and started really fighting the cravings. I finally gave in to the cravings and wasted a month eating carbs one day and then trying to lose the weight by going ZC over the next week. I ballooned back up to 190.

Five weeks ago, I decided enough was enough and went strict zero carb, nothing but meat and a little hard cheese. The cravings disappeared and I dropped down to 182 over the five weeks. It has been much easier to stick with this time around and I could see eating this way for the rest of my life.

Sorry this is so long winded, but I wanted to explain why some us zero carbers are zero carb because we have to be and not because we are deluded or following a diet religion. If 10 grams of carbs a day cause bad cravings, I don't see what eating at 10% carbs would do for me. If I had been able to start eating your way back in my no sugar days, I think I would be still be slim and trim. Unfortunately, I think 40+ years of gluten and carbs broke something.

August 20, 2009 | Unregistered CommenterRyan


Thanks for the post. That is very interesting. I will post sometime soon about why some need to go lower in carbs than others. I have been very careful to say I do not have evidence that eating ZC is unhealthy. No doubt some with a broken metabolism (damaged insulin sensitivity? pancreatic beta cell insufficiency?) after many years on the SAD will tolerate fewer carbs than those who never got that far. Perusing ZIOH, I get the impression there are quite few folks who had significant weight problems that led them to reduce carbs to the point of ZC.

It is only the idea that "man was not designed to eat carbs ever" and the idea that perhaps, those of us that still eat a few are deluded or addicted to them that I object to. That is why I said "right for the wrong reasons". The right reason is being and feeling healthier. The wrong ones are believing that "muscle cells do not use glucose", "paleo man never ate carbs", and other such nonsense.

Welcome and please be assured I consider 0% carbs as fully compatible with the PaNu approach as I agree there is no "requirement" for dietary carbohydrate.

August 20, 2009 | Registered CommenterKurt G. Harris MD

Thanks Kurt.

I am just trying to find out what works for me. I try not to get caught up in the minutiae.

I wish your way worked for me because I really miss the gluten free Thai and Vietnamese food that we used to cook. There is only so much you can do with just meat.

August 20, 2009 | Unregistered CommenterRyan

"No carb" is probably the easiest way to describe the idea of removing carbs from my diet since there's more reason NOT to include them than bother to include them. It's just the most convenient phrase to attach this to.
Discovering your blog has made it only more difficult to decide how to cook food. It seems like I can only speculate given the "Catching Fire" argument vs the possibility of AGEs having some significant effect.

More on UCP2:
"the level of UCP2 positively correlates with the postnatal survival of superoxide dismutase-2 mutant animals. Thus UCP2 has a beneficial influence on cell and tissue function leading to increased lifespan."

"Here, we report that high-fat feeding at 23 degrees C increased UCP1 and UCP2 levels in BAT four- and threefold, respectively, and increased UCP2 levels fourfold in WAT. However, at 29 degrees C, UCP1 decreased, whereas UCP2 remained unchanged in BAT and increased twofold in WAT."

"CONCLUSION: UCP2 and UCP3 mRNAs are upregulated by a high-fat diet."

Can read abstracts here, from a site that considers yours one of the more credible places on the web (along with PubMed).

August 20, 2009 | Unregistered Commenterwebster

Hi Kurt,

You wrote:

"For the record, I doubt if there are insulin benefits of going below 10% carbs and definitely not if you are eating more than 15% or so protein. An optimal diet like ratio of 80 fat 10 pro and 10 carbs will optimize insulin better than 60 fat and 40 protein."

Could you do a post on this? To me, this is one of the most contentious (spelling?) subjects in LC/ZC right now. Barry Groves says excess protein raises insulin, Mike Eades seems to say it doesn't. Ugh!

Secondly, and this may sound dumb, but how does one determine those ratios for themselves?

August 23, 2009 | Unregistered CommenterDaryl


Planning a post on carb ratios soon. In the meantime, excess protein is indeed converted to carbs then eventually to fat if not used as fuel. It takes insulin to handle the glucose and there is also some insulin response to dietary proteins, not as much as carbs but more than fats.

August 23, 2009 | Unregistered CommenterKurt G. Harris MD

Thank you for your prompt response!

As a Type 2 diabetic, I've seen wonderful results from restricting carbs; weight went from 260 to 150, fasting BG from 338 to the mid-80s, nearly a tripling of HDL, normal liver enzyme readings for the first time in over a decade. I just want to do what's best for my health, and this issue (the protein/glucose/insulin one) is the only thing still giving me pause.

On VLC (30 grams or less daily), I got the above-mentioned results, but didn't feel too hot. On ZC, I felt much better, had a steadier energy level, but am wary of "too much" protein. One theory that crossed my mind was, that on a high protein diet, one could see normal BG readings, but have higher insulin, until, a few years down the road, the high insulin would take its toll, perhaps wearing down the pancreas, then one would see a rise in the BG, despite restricting carbs.

Then, on the other hand, why didn't carnivorous peoples have weight issues? High insulin/BG should have induced that in them...

Again, UGH lol. Too much to think about sometimes. Anyway, I genuinely appreciate your time and efforts. I'll keep my eyes peeled for the ratios post.

August 23, 2009 | Unregistered CommenterDaryl

I think probably both the poster and commenters here are right- for a healthy person, there is little inherent danger in cooking; however, some people's digestive systems are so screwed up by a SAD their whole lives that they do best eating all raw (meats, that is).

We discussed denaturing proteins and AGEs; however, I didn't see anyone mention enzymes, which is supposedly the key difference between cooked and raw- even considering when meat is fermented or hydrolyzed by stomach acid instead of cooked. The heat is what destroys the enzymes (to varying degrees, which is why cooked rare is still better than well done). Although, perhaps you can correct me if it turns out stomach acids destroy enzymes as well. (They are proteins, aren't they...?)

Someone also brought up the compelling evidence of Pottenger's Cats. Now, I've heard it argued that cats are different than humans; but perhaps enzymes are still the key issue. I'm speculating that maybe cats can't produce their own enzymes as well as the more adaptable humans usually can. But perhaps some people today have lost their ability to produce enzymes, by way of their intestinal lining being too damaged by fiber or bacterial infection. I think of the drawing in Natasha Campbell-McBride's "Gut and Psychology Syndrome" with the sickened entrocyte, and it's "hair" being almost devoid of enzymes. Also perhaps weak stomach acid production will fail to trigger the pancreas to release its enzymes. Perhaps this is why some people must eat raw in order for their health to improve.

I believe Hugh is right when he says there is not much danger in dairy (pref. raw and grassfed), especially cream and butter... but once again, I believe this is only true for a healthy person. He pointed out that leaky gut is to blame in dairy cases, and I have a hunch that more people have leaky guts than are aware of it. Dairy might be causing all sorts of auto-immune or inflammitory damage to common people, not to mention becoming addictive, if the opioid-like casomorphins are in fact getting through. We must remember that it's entirely possible to live without dairy. Only 2 of the 12 peoples Weston A. Price studied were noted to have used dairy- the Swiss and the Masai. He noted that a Gaelic woman had never seen milk in the quantity of more than a few drops. It's hard for us to imagine, isn't it? Natasha Campbell-McBride says dairy may be resumed, but only after the leaky gut has been healed, which may take a few years. I noticed that you cautiously resorted to use the example of clarified butter, and I think any anti-dairy person would agree that that is okay- but that's not what most people use. (Although, again, what doesn't make sense to me is: how does the protein casein survive stomach acid? Or other "hard to digest" proteins like lectins and gluten in grains for that matter?)

My point is, raw meat and no dairy may not be necessary, but for people desparately searching for the optimal diet to cure their health, it makes sense. I just recently saw a show on PBS where Ethiopians, who looked to have pretty good bone structure, only ate meat about once a month. But when they did eat meat, they ate it raw, with spices, because they instictively knew that this would be the best way to extract all possible nutrients from what little meat they had. And I'm not sure about this, but I think they've found archeological sites where camp fires were regularly made, but the piles of animal bones were un-charred, suggesting that even though they had fire, they ate the meat raw. They must have done this for a reason.

Another issue that was brought up was whether or not excess protein converts to carbs and/or provokes insulin. While it's been documented that too much protein, in ratio to fat, will make you sick in a few days (for some reason), Michael Eades says that it does not convert to more glucose than we need, and therefore does not raise insulin levels. (However, in his book he does indicate that protein raises insulin levels slightly.) Barry Groves may have spoke out against high-protein diets, but he reminds us that most meat, even relatively lean meat, contains the majority of its calories as fat.

This is from Dr. Mike's blog, (http://www.proteinpower.com/drmike/ketones-and-ketosis/metabolism-and-ketosis/#more-719), so see if this is correct:

"Dr. Mike,

A lot of low carbers on various forums seem to be almost deathly afraid of protein. They seem to think that any protein not used for bodily functions is instantly converted to glucose, causing an insulin reaction and fat storage. I see comments all the time like “I am not losing anymore. I must be eating too much protein.”

Is there ever a scenario that excess protein is converted to glucose, except for the times mentioned in your blog entry?

Hi Ryan–

This seems to be a common misconception. The only time protein is converted to glucose is when glucose levels in the blood are low. When dietary sources of carbohydrate are minimal, the body converts protein to glucose, but converts enough only to keep the blood sugar normal. Any ‘excess’ protein can be converted to fat and metabolized as fat. But, for the most part, this doesn’t really happen because the cost of protein metabolism is high, therefore a lot of it gets consumed in its own metabolism. It takes about a gram of protein to make 0.7 gm of glucose, so if one is on a low-carb diet requiring an extra 70 grams of glucose production daily, it takes about 100 gms of dietary protein just to keep glucose levels where they need to be. And that’s before the protein is even used for all the structural needs of the body i.e., hair, skin, nails, bone, enzymes, muscle, etc.

Hope this answers the question."

August 27, 2009 | Unregistered CommenterJared Bond


enzymes? The enzymes you need to digest meat are created by your stomach and pancreas. This idea that the enzymes needed to digest food come pre-packaged with it (like the cow is thinking of our well-being?) makes no biological sense. I am not saying there are no enzymes in raw animal products, just that you don't need them to digest your food.

As far as plants are concerned, some have enzyme inhibitors that interfere with digestion unless you break them down by cooking.

Pottenger's cats were most likely taurine deficient. The experiment has never been replicated to my knowledge. Humans can synthesize taurine, unlike cats who are obligate carnivores.

I have no idea who "Hugh" is.

Dairy is tolerable for probably 95+% of those not eating wheat. Most will know who they are- they get a rash on their skin. Wheat is safe for 0%, IMO. If you are afraid of dairy don't eat it, it is not required, and neither is raw meat. I've never guaranteed dairy is as safe as eggs, but I refuse to tell people not to eat it based on the science I've seen to date.

Can you imagine the chorus of "monotonous" and "boring" if PaNu allowed zero dairy? Justifiably so. How can we convert people from the SAD by telling them to eat nothing but raw meat? I appreciate the transgressive aspect of an all raw meat diet, but I am interested in promoting health, not in social radicalism. (I have no tattoos or body piercings).

Did you know that 30% of people with B lactoglobulin allergy (from milk) are also allergic to bovine serum albumin from beef?

I'll bet they don't discuss beef allergies too much on the all raw meat forum.

Did you know that some people are allergic to other "certified paleo" foods we've been eating for millions of years - fish and eggs?

I think the bulk of our problems with milk are immune in origin, which is in turn influenced by the neolithic agents of wheat and excess linoleic acid.

Once again, my objection is not to eating raw or even the speculation that it may be healthier to eat some of your food raw. I know of no one who eats everthing cooked, even on the SAD.

My objection is to those who make a dogma of saying that it is unhealthy to have any food you eat cooked.

I eat my meat rare and I love sashimi
I eat my meat rare and I love sashimi
I eat my meat rare and I love sashimi

Or: Some of my best friends eat only raw meat! Peace!

As far as Dr. Mike's response, I'll just summarize my understanding thus:


Thanks for your comments

August 27, 2009 | Registered CommenterKurt G. Harris MD

Raw, zero carb, vegan and other extreme diets tend to be idealistic plans that focus on achieving a certain level of purity in the diet for a specific goal (be it weight loss, animal rights or superior health). Veganism and zero carb actually have something in common in this regard, imo. The vegan can brag that his diet contains no evil cholesterol (even though it is a necessary constituent for human health that the body will produce if not eaten, and usually in addition to what is eaten iirc). The zero carb diet contains no evil carbohydrate (even though it is a necessary constituent for human health that the body will produce if not eaten). Well, meat probably does contain a certain level of carb from the glycogen. In any case, they both tend to villify a vital component of the human body and often become ever more restrictive in an attempt to be pure followers of their regime.

Orthorexia nervosa: Is it a real disorder? Either way, dysfunctional attitudes to downright eating disorders can develop in some people who follow such puristic diets. First, they may develop a mainly dietary-related self-identity. Then their view of others becomes involved. In the raw vegan community I have seen the idea of toxic cooked foods progress to toxic cooked people! I think this can be a sad state of affairs and not health-promoting for anyone in the least.

This post has reminded me about making sound choices for my health, without getting too caught up in any unnecessary hype.

August 29, 2009 | Unregistered CommenterSatya

Great post!
I prefer my meat very lightly cooked or raw, mostly because I enjoy it more this way.
I used to sometimes visit the rawpaleoforum but I disliked the attitude there, people treat it as an 'all or nothing' thing, where you either eat all raw which is good, or you eat less than all raw which is bad...plus some downright questionable statements were made, kind of like the ones made by raw vegans (eg cooked food is toxic, all disease is caused by cooked food and that alone, cooked food makes you fat because your body must make fat to store the excess toxins , yadda yadda). The main scientific articles that were brought up were those on AGES, ALES and other heat created toxins...but I don't know too much about that stuff, do you think you could do a post on all these, and their effect on the body?

August 31, 2009 | Unregistered Commenterreamz
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