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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6s and 3s and the logic of grain avoidance


Although cows are herbivores, eating predominantly seeds is not really healthy for them either. Beef cows and steers are fed grains (grass seeds like corn) for the financial benefit of humans who raise them, not for the health of the animal. The animal naturally eats grasses. When you feed it just grass seeds, you are giving it something it previously ate in small quantities in huge amounts - a quantitative difference becomes qualitative. The animal will put on more weight faster, will mature quicker and will have muscle that is excessively laden with fat. This fat it adds will go from an n-6:n-3 fatty acid ratio of 1.5 -2 to more like 10, due to the outsize preponderance of n-6s in grass seeds. The chemical composition of the animal is now changed for the worse and it is worse for you if you eat it. You can imagine how many fish oil capsules it takes to re-balance the unbalanced ratio of grain fed beef. I believe its much more effective to just avoid the extra n-6s in the first place in the ways I have suggested. When you eat too many O-6s, whatever the source, your immune system is weakened against infection and there is evidence that cancer cell growth is promoted. 

The upside of grain for the farmer is higher profits because the animal can reach market weight and be sold a whole year earlier. This is why grass fed beef is more expensive, even it is not certified organic. (As a side note, beware of grass fed beef that is finished with grains to make it "tastier". The grass-fed animal can have its healthy 6:3 ratio ruined with as little as six weeks of grain feeding)

Now here is more evidence for avoiding grains in the optimal human diet. Can you see how the recommendation against grains is not predicated at all on carnivory? A cow is an herbivore eating no animals at all, is well adapted to eating only plants, can synthesize all its necessary amino acids from relatively monotonous plant sources, and is basically a plant-eating machine. Yet, we have just seen that feeding this herbivore corn makes it mature faster, gain weight abnormally, literally alters the chemical composition of its cell membranes, and as is evident to anyone who eats beef, the animal's immune function is seriously disturbed by the excess n-6 fatty acids. How so? Bovines fattened on corn must be given antibiotics to gain weight. This is because the grain-fed animal is more susceptible to infection. Now part of this is feedlot epidemiology, but I believe much of it is because the excess n-6s interfere with n-3 metabolism necessary for proper immune function. As a result of this antibiotic feeding, and perhaps also due to the immune disturbance itself, the cows gut is susceptible to e. coli overgrowth, and you have to worry about ending up with a colostomy every time you eat a hamburger.

Now if the case is compelling that an herbivore is healthier without grains and our health can be affected by eating the flesh of an herbivore that is fed too many grains, why isn't it reasonable to ask if an omnivore like us might not be better off without them? Before agriculture, seeds were a trivial to nonexistent, and certainly not necessary, part of our diet. The weight of the evidence here is pretty convincing. I have seen no evidence that any common grain (wheat, wheat flour, barley, oats, rice) was necessary for life before agriculture, and no evidence that they offer anything you cannot get with the huge variety of edible vegetables that have better vitamin, phytochemical and nutrient density than any grain. Of course, ounce per ounce, nothing can compare to an egg (even chimpanzees eat them) or lightly cooked piece of fish or grass fed steak for protein, vitamin and essential fatty acids. So I hope you can see that grain avoidance depends in no way on humans being "carnivores". We are further along that scale than what vegans or your average teenage girl in North America can accept, but that is simply not a necessary part of the argument against grains.

Cats and dogs are carnivores and can survive on fortified cereal when humans force them to eat it.

Cows are herbivores that eat nothing buts plants, but grains in their diet have negative health effects for them as well.

Humans are omnivores that now have a hugely expanded ecological niche through the technology of adapting rot resistant carbohydrate rich seeds that can be stored, milled, ground up cooked and eaten, mechanically planted and fertilised with the aid of petroleum, bred for higher yields, and even genetically engineered. Humans have thrived and expanded to 6 B souls on a finite planet despite the fact that grains are not an optimal food source at the level of the individual. Remember that the gene is the unit of selection. Grains are adaptive at the level of the gene and increasing human poplulation. Your genes do not care if you get coeliac disease, heart disease, diabetes, degenerative arthritis, tooth decay, autoimmune disorders, cancer or alzheimer dementia if by eating grains you were able to avoid famine just long enough to reproduce.

Look beyond the very misleading inter-country and even intracountry observational studies, which you could spend a lifetime trying to parse. Do pay attention to any controlled randomized trial that is well done. Do pay atention to the archaeological record. Do use some inductive reasoning with comparative anatomy, and ground your thinking with the best evidence from clinical and basic sciences like endocrinology and biochemistry. 

Start thinking about a diet that is not a diet at all, just a set of parameters that characterized 99% of our relevant evolutionary past. Huge variation in foods eaten, but no sugar, no mechanically produced white flour, and and few foods to which humans have had no time to adapt.

For most people in most places of food abundance, that will be a high fat, low-carb diet with no cereal grains.


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    Response: Protein Bar
    There are a lot of good opinions here. Really gives me a new way of looking at things.

Reader Comments (9)

Eggs. You said that you eat 4-5 a day. Are these regular eggs or do you have to get omega-3 reinforced eggs? I'm hard pressed to believe that I can get the latter in my work canteen in the mornings. I tend to eat a lot of hard boiled eggs (3-4 almost every day), but I'm concerned that these come from grain fed chickens, and thus, high in omega 6. Any guidance?

August 6, 2009 | Unregistered CommenterW.E.


I eat locally raised free range eggs from chickens that eat plenty of bugs. Search the blog for other comments on eggs.

August 20, 2009 | Unregistered CommenterKurt G. Harris MD

I'm just reading: "The Omnivore's Dilemma: A Natural History of Four Meals" by Michael Pollan and your information agrees with the book. It's a facinating book so far. The first section talks about corn, how it got its start in America and how it has infiltrated a huge percentage of what we eat.
Feeder cattle can only be fed a high corn diet for no more than a few months (despite the antibiotics) before the death rate rises far beyond the 3% industry average.


September 10, 2009 | Unregistered CommenterBob

Hi Kurt, I just found your site and I love it. I'm also a fan of Taubes's work, I'm glad to see he's getting his message out to MDs.

One problem with this post, regarding 3:6 ratios in grass- vs grain-fed beef. Grass-fed meat has a better 6:3 ratio, but if you look at the absolute amounts of 6 and 3, they're so tiny as to be insignificant. There's not even half a gram in a 4 oz serving of meat.

From the Weston Price site: http://www.westonaprice.org/farming/splendor.html

"One of the claims made for grass-fed beef is that the fat from grass-fed animals is much richer in omega-3 fatty acids.... But this is one claim that should NOT be made for pasture-fed beef."

Grass-fed is superior for other reasons, not because of omega-3s.

October 25, 2009 | Unregistered CommenterToban

Regarding eggs. I have been eating Christopher Eggs for the past 5 months. Each egg contains 660 mg of Omega-3....the highest I have seen. Kroger chain and its many wholely owned markets is the only place I can find them. $2.79/doz at my store.

On their site, I do have a big problem with their statement regarding saturated fat under the section WHY Christopher Eggs, GOOD Fats, Bad Fats
"It is well known that saturated fats are bad for us. Found in many foods including meat, dairy products, and some tropical oils, saturated fat increases the risk of coronary artery disease, diabetes and obesity. Recently, another culprit has been identified - trans fatty acids, which are man-made molecules produced during the hydrogenation of vegetable oil. Studies show that trans fatty acids can be even worse for your cardiovascular system than saturated fat and may also increase the risk of breast cancer."

At least they got the statement half right but its beyond me how they can make that statement about Sat fats!

October 25, 2009 | Unregistered CommenterDexter


As you can see if you explore the site, the step to grass fed beef is several steps beyond the step to eliminate plant oils - thus acknowledging that eliminating plant oils is most important.

However, I do not agree that the difference in 6:3 ratio in american beef fat is insignificant. If you ate a half pound of meat a day, one gram of PUFA that is mostly 6s will still significantly skew your ratio, once your total PUFA consumption is as low as it should be. It will only make no difference if you are swamping it with vegetable oils.

Weston Price Foundation thinks whole grains are fine, I think they are not fit for human consumption. One of many things I think WAPF is wrong about.


Argument by assertion. Say it often enough and everyone believes it.

October 25, 2009 | Unregistered CommenterKurt G Harris MD

This is probably the most convincing commentary on the paleo/no grain approach to diet I have read! Great work!

I find the most common misconception people have about grains or adopting the paleo approach is not indifference but that we 'need' grains for some reason or another. I myself have been using an example (which now seems inferior to your cow example!) that since grains played no part in humans diet for 99% of our evolutionary history, that the idea grains are beneficial to humans is as plausible as them being beneficial to ANY other animal! Imagine positing that a saltwater crocodile (or a cheetah if you want to keep it within mammals) may have more energy or be 'better off' if they added some grain carbohydrate to their all meat diet! Infact all you would probably get is the first ever fat crocodile!

Kurt, this post is also a test to see if you receive notification of comments on older posts... I have come to this post trying find the earliest articles on your blog. Under the "PaNu INDEX" this is the earliest I can see, however your writing would suggest there is more, how could I find the start?


I think they start in late may or June. There is a thread on itulip with more of my writings if that interests you. Look for the link in the essay "the panu mission".

November 11, 2009 | Unregistered Commenterbend.

If a cell only has the ability to hold a finite amount of Omega 6's and 3's.....and we supplement with fish oil to get our Omega 3's up to 10-12% of the cells capacity.....would it not alleviate the argument of worrying too much about the Omega 6's as they will have nowhere to go? I thought this one of the main arguments for supplementing with Omega 3's?

This may be one of the areas we do not fully understand yet but I am curious of your views....


Search Stephans wholehealthsource website for omega 3's and Pufas and Lands (author).

Total pufas should be low, then supplement if necessary. Better to cut 6s as low as possible, and only then add CLO. To get a good ratio without reducing 6's first is almost impossible and if you don't reduce 6s first your total pufas (which are still subject to oxidation even if 3s) are too high to be healthy.

November 12, 2009 | Unregistered CommenterKen Oursler Jr.

Can an e. coli infection actually lead to needing a colostomy, or is this hyperbole?


Not hyperbole - I've seen it - it can also kill you.

January 7, 2010 | Unregistered CommenterTod
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