Kurt G. Harris MD

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 an animal-based diet high in fat, low in cereal grains and relatively low in carbohydrate.

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The Paleolithic Principle - the PaNu Version

Reader Bend comments in response to a thread about whether we should emulate paleo man by letting our vitamin D levels drop "naturally" in the winter:

"Whilst of course there must have been many groups of hominids throughout history suffering deficiencies (or just not 'prospering'), I find it quite implausible that overall they were not in perfect health! Go into nature and you see so many examples of animals living in accordance with their evolutionary history in perfect health. A wild bear after salmon season, a lion who has notched up 100's of kills over his lifetime. A whale, a fish, and so on. Could we study these animals extremely closely and find they are a bit short on something here or there? They would do better if they had a little bit more of this or that? Its hard to imagine it. This is a question I have been giving a lot of though to recently. Are humans' ability to so easily find themselves out of optimum health a consequence of our discordance with our evolutionary past, our absolutely unique H&G style of food acquisition, or just simply an artefact of huge amounts of extensive scientific study (ie if you had performed the 10's or 100's of thousands of tests and studies on a whale or bear you would have similar conclusions)? Through evolution hominids have become adapted to an extremely wide variety of food sources both plant and animal. We didn't get to becoming the most successful and adaptable species on the planet for no reason! Or is it possible evolution traded optimum health for diversity? As we see from SAD, even with doing just about everything wrong we are flourishing in terms of reproduction..." 

My response:

1) My central thesis is that certain aspects of current ill health are due to behaviors that are substantially outside our evolutionary experience - these I tautologically define as the "diseases of civilization" and they include the effects of eating the neolithic agents (DM, Cancer etc.) and behaviors such as lack of adequate sun exposure.

2) The truth of #1 does not imply that any condition experienced during the evolution of an organism is by definition perfect health. After all, most species that ever lived were extinct long before being threatened by homo sapiens, and those that survive do so as vehicles of their selfish genes. A modern or postmodern idea of "health" need not speak to whether their health would have been optimal by our standards. Example: would you trade not eating wheat for suffering a homicide rate of 25% as was documented in some paleolithic peoples? Or shall we practice infanticide as a healthier alternative to synthetic hormonal birth control?

3) A corollary of #2 is that we can conceive of any number of health measures that not only could be, but probably would have to be worse by our own standards in the paleolithic period. My version of the paleolithic principle is limited to what I define as  correcting diseases of civilization being cause by evolutionary discordances in behavior, mostly diet. Not every current measure of ill health is caused by evolutionary discordance, and the condition of paleolithic man in toto should not be our current definition of health. That is a giant non-sequiter I try to avoid - a version of the naturalist fallacy.

This is why I spend so little time speculating about what "grok" did (at least on the blog) and how idyllic and lovely his existence was. It may be fun to speculate about, but the diseases of civilization need to be related to evolutionary history by first having a modern understanding of the diseases, and then filtered through a scientifically informed historical narrative.

From a pure evolutionary perspective we are actually doing everything right - evolution does not care if we get cancer or diabetes after we reproduce. From the perspective of the gene, trading the increased fecundity we got with first early neolithic and now petroleum-based agriculture for any ill health effects that resulted was a great idea.

I think looking at wild animals as "perfectly healthy" in their totality is neo-Rousseauism and I would caution those who romanticize the health of other organisms by human standards. Such an attitude may actually be a bit anthropocentric and condescending to the true suffering of all animals, both human and non-human.

Nature is beautiful, and it is trying to kill you.

Reader Comments (11)


Vieth had a paper published in the Sept 2009 issue of anticancer research that somewhat addresses this issue, he suggests that seasonal variations are probably a bad thing.


Can't grab the full text from my university portal (have to actually goto the library ugh), but found it on slideshare

November 26, 2009 | Unregistered CommenterChris

I think that one should always derive theories from evidence, not evidence from theories as they do in the Church of Evolution. What's the primal "soup" made out of this week, Mr Dawkins? The evolution of life cannot be reproduced in a lab so why not determine how the body is put together today? We can do that, partially- So I'll continue supplementing with D3.


I am quite firmly a member of Dr. Dawkin's "church" and in no way do I question the fact of biological evolution. Actually I am sure more mischief comes from theorizing based on observations than comes from observing with a theory in mind- witness current economic thinking.

My point is more along Harris' first axiom of science and design - it is best to proceed from the known to the unknown. In this case modern medical science should be the starting point, then we consider the evolutionary milieu.

November 26, 2009 | Unregistered Commenterzach

Hi Kurt,

and thank you so much for your blog! As a zone >> lactopaleo >> kwasniewski lowcarber (one gets to test a bit in a decade), I agree and follow your style in most aspects of diet. It is always fun to see folks turn into similar conclusions, in spite of different paths in thinking, experience and education. And it is even more fun to see ideas evolve, in blogosphere & internet (from RedFllagts and zoneHome community to peter, yourself, stephan and others) as well as in real life & science (from Darwin to the most fascinating Nick Lane).

So, just as an experimental report, on vitamin D:
- Prior to lowcarbing our family were imflammated several times a year (in seasonal flus and/or colds), every year. I, personally, was much more affected than the rest of the bunch, as my chronic allergies started at 11 months of age.
- As for D doses: We live up, up north in Scandinavia. We have not used any vitamin D supplements for the last 5-6 years (at least), and mega doses never. We live modern life in urban environment, meaning that exposure to sun or outdoor life is not that strong. We eat little or no fish, (as I'm allergic to fish but still do all the cooking), and unlike the dairy of old, our market-bought cream and high quality butter (I use lots of both) is supposed to be low in vitamin D.
- However: we have nearly zeroed all detectable imflammations, upon starting on lowcarb. Or rather, during the first years, colds arose when occasianally eating "more normal" (say under holiday seasons). And yes, the offspring got reallly sick when doing their compulsory military service under very grain and Pufa laden "official healthy diet". And yes, I had one last summer (right after the biggest annual exposure to vitamin D), but that was my first one in years. But that's about all.

So, as an experimentalist I am curious on the effects of supplementation (especially in megadoses) when living on reasonably real food. In the lowcarb community that I've been following for years, the vitamin D megadosers do not seem to report less imflammatory problems than those who do not. Food quality seems to matter much more, even there.

Thanks once again and with regards,


Thanks Leena

I don't think anyone claims D is generally "anti-inflammatory" as much as enhancing the innate response and attenuating some of the adaptive. My own allergies and IBS and many others reports with autoimmune diseases show response more to gluten grain and PUFA elimination - in fact I had improvements as well on VLC even before supplementing with D.

Part of what you are observing is that many illnesses labeled "infection" by medical doctors are in fact allergic rhinitis or non-infectious - so you are probabably conflating infections with vasomotor rhinitis. etc that are not infections.

It is plausible that higher D levels are required epidemiologically as an artifact of the SAD (as seems to be the case with C) but to live in Sweden without at least testing your levels seems to me a risking way to test the hypothesis. The anti-cancer effects have nothing to do with symptoms of inflammation or allergies and these effects (or their lack) will only be seen if they are not there - if you get cancer.

So I view D as anti- infectious and anti-cancer but not as generally anti-inflammatory as gluten grain and PUFA elimination.

November 27, 2009 | Unregistered CommenterLeenaS


I love your blog. And I love this post. Thinking rigorously is a great way to sort things out. So, please take what I have to say in the way it was intended, i.e., critical support.

By rewriting your two primary theses, I believe that I have come to improve my understanding of them. If you think that my reinterpretations change their meanings, please correct my misunderstanding(s).

First, I will use the term "paleo behavior" to refer to what you call "evolutionary experience," merely for the purpose of increasing clarity.

Thesis 1: Some nonpaleo behavior causes disease.
Thesis 2: Some paleo behavior causes disease.

Now, these two theses have some content, after all they are both falsifiable. For example, it might have been the case that all nonpaleo behavior causes disease and no paleo behavior causes disease. In that case, the Rousseauian naturalist would be standing on firm ground. But the content provided by those two theses is rather thin. It suggests that the category "paleo" is not particularly helpful for distinguishing disease-promoting from health-promoting behaviors.

You do explicitly state that we need to use science to tease apart the healthful from the nonhelpful behaviors. And, of course, I would concur. Then, we have to ask ourselves whether the "paleo" category serves us in any way. After all, just because something is paleo, does not mean it is good. So, regardless of its origin, we must examine each behavior (singly and in combination) to determine its health-affecting properties.

So, I take my analysis, above, to be a restatement of your larger point that evolution and nature have different criteria for health and disease than we do.

November 27, 2009 | Unregistered Commentermoises

So you don't think anyone claims D is generally "anti-inflammatory" as much as enhancing the innate response and attenuating some of the adaptive? Maybe so. Yet according to the school book from early 70's - or fresh vitamin info (internet, lieaflets, health books) meant for non-professionals, the lack of D is connected with weak bones, bad skin and imfllamation symptoms.

My skin, teeth, and allergic/imflammatory responses were affected by changing other things, not uptake of D. I even tan nowadays in sun, for what limited amouts I happen to catch during the summer. Furthermore, for what I know of the the people living here 100-150 years ago (not quite Sweden but close), D or even the sun itself did not seem to be a major health parameter, any more than excessive excercise or a very lean body. Good nutrition was, though.

Cancer is scary as it may evolve for decades. My mother got that youger than what I am now, and quite a few other wasting diseases are not uncommon in my kin, either. Yet a true causal relation is hard to catch even in the supposedly clear cut case of tobacco, due to confounding factors (how could 70% of japanese smoke and sitll have lower lung cancer statistics than westeners). Or what is the real effect of p pills and HRT on cancers - for those not eating like western ladies? I'm just trying to say that the dietary confounding factors are pretty huge nowadays. Ot that the optimal conditions (or leven ab readings) while living on SAD may be different from those living on more whole foods - even just for the 80/20 deal.

So I see your point. And agrteed, you may well be right, but don't see the evidence (in the case of vitamin D).

With regards,


Hi Leena

"Inflammation symptoms" is a pretty vague term. I am trying to point out that improvements in allergies when wheat is removed is no evidence at all that D has no effect on other aspects of immune function and restraint of abnormal cell growth.

What evidence about D is it that you are not seeing? Have you read any of the papers I referenced by Vieth, Cannel, et al. There is clear epidemiologic evidence of variance in D deficiency, cancer and MS with latitude

If you are only saying D deficiency may be more significant to health when on the SAD, then I would agree. In the same way, if you are a smoker and eat no sugar, you may well have less lung cancer than a north american, but that is not saying smoking is not a cause of lung cancer.

November 27, 2009 | Unregistered CommenterLeenas


You said:

"...But the content provided by those two theses is rather thin. It suggests that the category "paleo" is not particularly helpful for distinguishing disease-promoting from health-promoting behaviors."

That is why I don't agree that your condensation of my wordier hypotheses is the same.

Fo one thing, your two statements are theoretically falsifiable, but in practice the first one is pretty tough to test as you have written it.

See the next post later this evening.

November 27, 2009 | Registered CommenterKurt G. Harris MD

I would quibble that
"From a pure evolutionary perspective we are actually doing everything right - evolution does not care if we get cancer or diabetes after we reproduce. "

isn't set in stone because it seems longevity in humans was selected for because of the positive role in grandparents improving the odds of survival for their children's offspring.


Your objection would make sense to me if cancer and diabetes were the usual way we died in the paleolithic or if they struck at age 30 . It was not and they do not.

My point is there are 7 billion of us - the only definition of evolutionary success - and cancer and diabetes are not being selected against. That is what I mean by evolution not caring. I am talking about grandpa being sick more than dying early. Actuarial life span is greater now even with cancer and diabetes. Plenty of babysitting to do before grandpa gets the cancer at age 60 - grandkids are fighting in Iraq by that time.

November 27, 2009 | Unregistered CommenterMelissa

'From a pure evolutionary perspective we are actually doing everything right - evolution does not care if we get cancer or diabetes after we reproduce'

Yeah but Kurt, we have to raise our children, for ages. If you die of cancer prematurely, your kids are left without their caregivers. I would say the longer you can stay in good health the better chances your offspring will reproduce, giving an advantage to any organism over another that is neither here nor there in regards to its health after it has reproduced. Hence we are the descendants of people molded by the evolutionary pressures to keep our health even after we reproduced.

This is not the first time I have seen that written.



What you are missing is that most cancer deaths begin occurring at an age where children and even grandchildren are old enough to fend for themselves. There has to be selection pressure for cancer to be selected against. If you get breast cancer even at age 50 and die from it, your children are already born. There would have to be selection pressure at the group level for genes that resist cancer - that is not concievable with modern social arrangements, which if anything select for bad behaviors by subsidizing them.

I stand by my claim.

November 29, 2009 | Unregistered CommenterKennedy

I completely agree Dr Harris.
I respect most primal-paleo principles just to have a better health.
I cannot refer to Grok as an example or my Guru.
I just know that a sugar based occidental diet is scientifically inflamatory and that inflamation is tied to diabetes, cancer, parkinson etc...
Thanks for everything and mainly your "cool headed" approach that helps me explains my way of eating to friends without them thinking I'm insane...

November 30, 2009 | Unregistered CommenterG

I agree that wild animals aren't the all to end all perfect specimens of what health can be. Wild animals seem like they have their fair share of misery, too, even if a bear after a big meal of salmon looks pretty darn happy. Parasites, flies in the eyes, huddling together in large groups to stay warm in the winter despite having thick coats, scars/injuries from fighting amongst their own species or defending/hunting against/for other animals. All of these things can happen to humans and we generally do our best to avoid them. A human with any of those things and any number of things I didn't specifically mention is usually considered to be unhealthy from one perspective or another.

December 1, 2009 | Unregistered CommenterKD

Especially Vieth can be interpreted also differently, as Peter just pointed out in Hyperlipids (two blogs in Dec 2009 Hyperlipids). I tend to agree with him, as it seems to fit with pretty much all the evidence I've seen so far.

But then again, my paleo glasses are somewhat tinted to begin with, with Sir Hardy's aquatic ape theory (that pretty much kills the savannah theory), with Kwasniewski's style (which seems work very well for my family living up here) and with some written and some first hand descriptions of the former lifestyle up here during times before the WW-2.

Still, it is interesting to see data analyses and hypotheses on how latitude, vitaminD, cereal fibres, fructose, plant Pufas, animal fats and cholesterol/plant-sterols do affect each other, especially since there is not that much published long term data of people on LCHF in the Pubmed litterature.

With regards and thanks for your thoughts,


I read Vieths' paper before writing this. If the major variable is a steady level and not a high one, this also favors supplementation, unless you want to use a parasol and avoid the sun in the summer. Also, Vieth is explaining away the paradox related to two types of cancer. The other common cancers need less explaining, and the optimization of other Vit. D effects may also not.

Our evolutionary history with steady equatorial sun exposure is much longer than the more recent high latitude one post- migration to europe. It is possible that we remain more adapted to the former, if only because it would avoid D declines. Genetic disadvantages can persist unless selected against, and this mechanism hypothesized by Vieth may be one of them. Vieth's paper at the least debunks the idea that one should mimic paleo D levels by letting them fall "naturally" every winter. This may have happened and it may not have been fully adapted to.

This is the point of my essay. Avoid the naturalist fallacy and pay attention to current science first.

December 8, 2009 | Unregistered CommenterLeenaS
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