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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« What I eat | Main | Do you believe in magic? »

Plants and plant compounds are not essential or magic

Show me a randomized intervention that shows the benefits of fruits and vegetables. Such trials have been done and they have not shown a benefit. Same as the trials to limit fat consumption.

It's "lets see what (olive oil, resveratrol, blueberries antioxidantss - insert name of magic chemical here) does in a test tube or in mice. Look, one of our many experiments shows something! Humans must have evolved to be dependent on this substance to optimize their health.

Look, I don't read everything but I read a lot. I am not interested in dying early. The minute I see plausible evidence of some magic supplement working or an essential plant that is not commmon to all humans, I'll be the first one to promote it.

Analogical reasoning (wolves eat leaves, therefore,,... ) is not enough. We need a plausible biochemical explanation combined with robust epidemiological evidence (rare) or real proof from an intervention.

To overcome the inherent implausibility of a particular compound or plant being essential or uniquely beneficial to health, there must be a high standard of proof.

Similar to the level of proof there that there is extraterrestrial intelligence. It's implausible, so good evidence is needed. If we believe, as I do, that the key to health is avoiding neolithic agents of disease and that the common element of all healthy populations is animal products, how can it be that any plant that was not universally available is essential to health? It is not impossible, but in the scientific sense it is highly implausible if you accept my other premises.

I am not really that interested in what is possible - more so in what is very likely to be true.

Part of this is philosophical as well, applying the 80/20 rule to health. I think the idea that one should micromanage dietary constituents based on speculative reasoning about magic special compounds is not only wrong, it is a big waste of time. There are many other things to occupy your time with.

Counting, measuring, weighing and titrating food and and researching supplements and special foods? I have zero interest in that, as I'd rather practice my guitar or read a good book.  

Reader Comments (33)

I love it when you talk like this. :-) I enjoy a good veggie from time to time for the taste experience, but my diet has been pretty close to zero carb for the last couple months, and I'm perfectly happy with that too. I enjoy meat, I enjoy eggs. I had commented on your blog over the summer about how my weight loss had been stalled for months despite a low carb diet (and still having a ton of weight to lose). But since going mostly zero carb (and no snacking, a smaller eating window) I have dropped 18 more pounds. And I feel great.

Unfortunately things are not quite so great medically. My fasting blood sugars are still high and my doctor has put me on metformin, my blood pressure seems to be going up rather than down, and I've been put on a blood pressure medicine. And now just this week I've been diagnosed with Hashimoto's Thyroioditis and put on thyroid supplementation!

But I have had people in the low carb community telling me that my diet has brought on my thyroid issues, and that eating close to zero carb will seriously depress the thyroid, In essence telling me that it's all my own fault, and I better start trying to eat at least 50g of carbs and better yet 100g daily. I don't really *want* to give up VLC as I feel the best on it. But there are opinions and 'facts' to support every possible eating style and viewpoint it seems.


Hashimoto's is autoimmune. It may take good conventional medicine to take care of it - its moot whether you got it from diet (gluten grains- molecular mimicry) and it will not likely be fixed by varying your carb content at this point one way or the other. Stay away from grains of course. Work with your doctor to get your thyroid squared away, then the diet will work for you.

How high are your fasting blood sugars?

Fasting blood sugar can rise to the 100 level on VLC or ZC.


On VLC or ZC?

What is your HBA1c? Have you had an OGTT done after appropriate preparation?

If you really have diabetes, there is absolutely no reason to eat any carbs at all. Read Bernstein's book and give a copy to your doc. If I were type II I would be zero carb.

With that degree of weight loss, it is hard to imagine it was not from the diet, but Hashimoto's can make you hyperthyroid and that raises your metabolic rate. These things can be hard to sort out - work with a good doc, preferably an endocrinologist.

November 10, 2009 | Unregistered CommenterDebbie

amen, brother.

November 10, 2009 | Unregistered CommenterDano

Exactly. Of course, I have seen them take people eating lots of soda and twinkies, cut that part out, feed them nothing but salads and surprise, they improve. Therefore, we should minimize fat. I have seen recent animal studies involving monkeys where they do a variation of this: They feed one monkey a gourmet quasi vegetarian diet, and feed the other store eggs scrambled to death, fried processed mystery meat sausage, white bread toast and gmo grits with lots of processed butter from confinement animals for breakfast. Likewise for lunch and dinner. Then, when the vegi monkey is in better health than the other one, they conclude we should limit our animal food intake. Maddening!!!

November 10, 2009 | Unregistered Commenterzach

Should Debbie test for celiac?


Why test for celiac unless you want an excuse to eat wheat? If you test negative, you are probably one of the 80% of the population that has "only" the innate response.

November 10, 2009 | Unregistered Commenteranonymoue

The continued belief in a magical plant/plant compound baffles me. Every year, the multilevel marketing crowd comes up with a new panacea (cures everything from athlete's foot to cancer) for that year. And people buy the hype.


Blue-green alga, noni, mangosteen, aloe vera, acai (this is the latest and greatest) ad infinitum

It blows my mind that ostensibly intelligent people jump on a new bandwagon every year buying these "supplements".



On another note, I found this quote of yours that I think is the best summary of Paleo eating I have seen. Concise, accurate and well-put.

"The PaNu EM2 is not a diet composed of prehistoric food items, it is a metabolic state that we are trying to live in while eating foods that exist now.”


I think if you look at the ingredients on Monavi it is mostly sweetened fruit juice - I don't even like to pay $35 for actual wine. Single malt, maybe.

Thanks for the compliment.

November 10, 2009 | Unregistered CommenterPatrik

Are you saying there's absolutely no point in researching supplements? I believe that supplements are the key to improving health beyond what's possible just based on diet. Of course, lots and lots of them do close to nothing, but supplements can sometimes be beneficial. For example, piracetam, from what I've researched, has been proven to enhance memory and focus and help prevent the onset of some degenerative diseases.

November 10, 2009 | Unregistered CommenterDima

Extra terrestrial intelligence. Lawrence Krauss gave a great lecture at the 2009 AAI conference which can be watched by following the link.

In it, he says the latest evidence points to an accelerated expansion of the universe (flat, iirc). (Of course, I often feel that the looking farther into space means looking further back in time fact is not always well accounted for with some of these theories). Anyway, he says that in the distant future, any life forms will look out in the sky and see only evidence of their own galaxy. Even the CMB will be so far away it will be undetectable. IOW, any future intelligent beings will have no way of knowing of the origin or fate of the universe. Poor things. But in this case absence of evidence will not mean evidence of a steady state universe!

Back to plants: I definitely do much better severely limiting plant foods. There are just so many issues with some plants, such as; oxalates, lectins, alkaloids, and more. But then, certain minerals like potassium are found in some of them. So I do indulge in a salad with cucumbers from time to time. I have really found that seaweed is a super addition to a carnivorous diet. It is high in many minerals and just doesn't cause the problems that plants do, maybe because it is not a sea plant but a protoctist.

Finally, Dr Harris, can you comment on any casein connection to Hashimoto's? Like gluten, it has opioids, and I have seen some professionals recommending a gluten and dairy free diet for it. Thanks!

November 11, 2009 | Unregistered CommenterSatya

i absolutely get you on this idea of 'magical compounds' but how about the common sense benefits of fruits and vegetables? humans without a constant food supply need fat stores! they aren't going to get that from animal products.

there's a woman that is 5'7" 112 pounds, hasn't had her period in years and asked for help gaining weight. she wants to get pregnant but she eats no plants so she is in constant ketosis! she's been waiting for over 2 months for someone to tell her to eat a freaking apple or a potato (or you know, a milk shake!).

it seems pretty obvious to me that she simply needs to eat some carbs. she'll never gain weight in ketosis no matter how many calories she eats. the situation isn't perplexing. ketosis is great if you have fat stores, but it is not conducive to getting pregnant. you can have your pet theories about what the healthiest diet is (i'm on board that it's primal, but not with a constant state of ketosis), but the human body has biological needs and you can't force it to be fertile with theories.


Lot of hostility there, Laura. I am glad everything is so obvious to you. Do you think she is waiting for permission from me to know what to eat? Do you think she has not been told to do that or tried it already? Have you seen my other writings where I argue against the Zero Carb dogmas and say it is fine to eat carbs in some amount, but they are not necessary. I guess not.

It is, as you say, common sense that gaining some weight is more easily achieved by eating carbs. Who the hell doesn't know that?

I don't practice medicine over the internet.

The current literature suggests that in those with history of eating disorders, restoring energy balance (not weight) is enough to start menses, but there are many, many causes of infertility.

As far as your assertion that plants or milkshakes are obviously necessary to gain enough weight to be fertile or even to gain weight in general if you are underweight, you are wrong.

Or perhaps you could explain why the fertility rate in HGs that eat no plant matter is not zero?

November 11, 2009 | Unregistered CommenterLaura

I think there can be more to it than not eating wheat. I am glad this "diet" is becoming more widely known and seems to growing in popularity. It will help many people stay healthy and it will help others restore their health with very little effort. But grain elimination is bound to uncover a few celiacs and their return to health may not be effortless. They may need screening for osteo problems or addiitional nutritional support or an "authoritative" reason for their dietary preferences should they ever be hospitalized. Some one with Hashimoto's Thyroioditis, which is linked to celiac, perhaps should test now? The opportunity to get a clear diagnosis will perhaps diminish after awhile on a nearly gluten free diet?


You certainly make good arguments. It is everyone's dscision. I have outlined the main problem, which is that a minority of people with autoimmune disorders will have gold standard celiac. Bayesian reasoning would tell us that the most likely outcome is false reassurance.

The bone health issue - I believe and evidence shows that gluten avoidance and D supplementation will rapidly correct your bone density, and anyone ating PaNu is doing all they can in that regard already.

I would not get tested. Other experts disagree with me, but their reasoning assumes the subsequent lifetime consumption of SAD mimicking garbage that is "gluten free". If you eat truly paleo, you are never eating anything that comes with a label.

I tell friends with kids in school who want to keep their kid from being fed goldfish crackers and juice boxes every 15 minutes to tell a lie - which is not really a lie - and say "I am sensitive to gluten grains". I honestly believe that is true for every human. It works well when getting substitutions done in restaurants, I am told : )

November 11, 2009 | Unregistered Commenteranonymous

Forgive me if this is ignorant, but what about the antioxidant properties? Is that not a pretty well understood and basic biological function which suggests is beneficial? What about the notion that a carnivorous diet is all that is essential, or even perfect, but including plant compounds (along with meat) is 'enhancing' or is there no evidence of this and I am missing the point? Unfortunately this is where my layman thought process meets the end of my arm chair


Supplementation with antioxidant vitamins has failed to show benefit in human trials

Adding plants to your diet make it more interesting, but it will not add to your health. I came to this conclusion despite initially believing that fresh vegetables and salads were great. I still like the taste, but when you look at the supposed benefits one at a time, even ignoring the secondary compounds, they are all myths

Fiber is at best useless and feeds the bacteria in your gut

Starch is unnecessary and can feed the bacteria in your gut if not digested fast enough

Simple sugars are unnecessary and can raise your blood sugar, make you fat, etc. Fructose is particularly poisonous in suprisingly small amounts.

The vitamins and other micronutrients in plants are all either better proved form animals or were only considered essential as compensatory supplements in a diet filled with grains

Eating plants for their antioxidant proeperties is at best entirely unproven and may be counterproductive.

More posts coming up.

November 11, 2009 | Unregistered CommenterPaleo Lens

HOLY EXCUSE ME LAURA- Do I know you? Have I met you? NO- you do not know me or anything I have or do go through. Permission to eat a potato or milkshake? Hell no I do not want permissions to eat a flippin potato or sugar laden milkshake nor would I even if Kurt told me to(which common sense would tell him to stay out of it all together and let me make my own choices- yes I am sorry I started the menstruation question up, it was out-of-place). I asked for an opinion on ketosis, VLC and fertility.. I did not ask whether I CAN gain weight. Your incredibly wrong to state that one can eat a million calories in ketosis and not gain weight… please study the body and it’s functioning… excess protein AND fat can be converted to glucose and stored at fat in the body. Kurt makes a point that is ketosis had anything to do AT ALL with infertility humans would have died out like way long ago. And I must intrigue you for some reason, because LORD you show some hostility toward me

And by the way thanks- I have tried conventional “treatment” if you’d like to call it, that for anorexia. I’ve lived months with a ½ gallon of ice cream a day, potatoes, starch, meat, nuts, veggies…. It was an absolute living hell and accomplished absolutely nothing. Do you somehow think I haven’t been to the doctor and been told to shove my face with mashed potatoes and spaghetti?? I’ve been told a million times to do just that- but in my heart of hearts DO NOT agree with it. I DO NOT agree with anyone eating anything that doesn’t spoil, go bad and is not real food. I think what is sold as “veggies” at the market these days are full of crap, lack any nutrients they are supposed to have and have been grown in shit soil.

I do eat a tremendous amount of eggs, liver, meat, raw cheese/butter/ghee

November 11, 2009 | Unregistered Commentermallory

Keith is spot-on with regard to celiac/gluten testing and false negatives. Two years ago before I started eating Paleo, I had a suspicion that I might have some sort of food allergy. They tested me for wheat, gluten etc etc...and nothing turned up.

About a year later I succeeded in cutting out grains altogether and my life changed forever for the better. This is not hyberbole. Had I listened to the conventional "medical wisdom", I wouldn't have experimented with Paleo and would have been much worse off for it.


I assume you mean Dr. Harris or Kurt, no Keiths here :)

November 11, 2009 | Unregistered CommenterPatrik

There is a world of difference between stating, plants are not essential,
and, dont eat plants.
I suspect some are interpreting something into this piece that simply isn't being said.

For what its worth.

KGH: Coffee is not essential. I drink coffee. Only one example.

November 11, 2009 | Unregistered Commenterj

i wasn't feeling hostile at all - but when i re-read my comment, i can absolutely see how it come off that way. i dealt with infertily issues and my sister was anorexic for a time - i was actually feeling very compassionate toward you mallory. but i can see how it came off as condescending and i apologize. i know a milkshake isn't good for you and i definitely know it's not the only way to gain weight. good luck with finding what works for you mallory.

November 11, 2009 | Unregistered CommenterLaura

I agree with you on this, and your reply to Paleo lens, that they can be used as a compensatory means in a diet filled with grains. I'm thinking Middle Eastern cuisine top-heavy in Gluten being saved somewhat by the Turmeric Spice.

Good recommendation with Nephropal, seems like a very good blog so far.

You're also running a great blog here, respect!

November 11, 2009 | Unregistered CommenterKennedy


Whoops. I mixed up Kurt Harris with Keith Norris who also runs a great Paleo-focused blog.



That would explain why someone else made the same error :)

November 11, 2009 | Unregistered CommenterPatrik

"It is, as you say, common sense that gaining some weight is more easily achieved by eating carbs. Who the hell doesn't know that?"


November 11, 2009 | Unregistered CommenterJoe

Would there be any concerns with getting adequate vitamin C w/o fruits and veggies?

November 11, 2009 | Unregistered Commentersandra


I've personally being eating a VLC/ZC diet for over three months. I haven't consumed anything with Vitamin C in it for four or five months. I'm fine.

You probably should do some more reading, both on this blog and elsewhere. The Vitamin C canard has been refuted on virtually every Paleo-type site out there.

November 12, 2009 | Unregistered Commenterpfw

i really dont think vitamin C is as necessary as it is conventionally presented. when there are carbs from crap in the diet, then yes Vita C may be good in mega doses... liver i think contains vitamin C too... if anything i think the effects of vitamin D mirror what people think of vitamin C

November 12, 2009 | Unregistered Commentermallory

Several months after I went Paleo (no grains, dairy or beans) my doctor did a blood test for gluten sensitivity. This is what the report says:

"the absence of IgA anti-TTG antibodies makes gluten sensitivity very unlikely provided there is adequate gluten in the diet"

Note the words in bold - so you can't be tested when you're already gluten free and that kind of proves that it is only if you're eating gluten containing foods that you can suffer from them...why on earth would someone want to eat something that causes problems ?


KGH: social conditioning is powerful

November 12, 2009 | Unregistered CommenterAnne

I like decenting opinions....after all that is what brought me to the Paleo Community (Marks; Daily Apple, Track Your Plaque, Animal Pharm, Hyperlipid, Nephropal, FatHead, Free the Animal and PaNu). So I am always open to different lines of thinking.

I have read and re-read your latest post and am very surprised by it. You are careful to use the words dependent, magic, essential and others, so I am having trouble understanding if you believe there are ANY health benefits from blueberries, wine, cocoa and the lot?

This thought pattern does fly in the face of hat many write abut but does have me, once again, thinking.

Do you see any value in the resveratrol and antioxidants many do believe help fight oxidation, inflammation, cancer, disease, etc? Are these foods not part of your diet?

Still trying to digest this one. Looking forward to your elaboration on this timely topic.


Correct I don't take any plant derived supplements. I eat a few blueberries with cream for flavor. Seeking antioxidants from plants is not proven or even very plausible in my view. I have read some info that implies it may be harmful in fact. More to come later.

Bluuberries are full of fructose which is a an oxidizing agent and a hepatotoxin.

My view is plant worship is the politically correct residual of mainstream health food thought that is still infecting the paleo/primal world. Not saying don't eat plants. Saying they will not save your life.

November 12, 2009 | Unregistered CommenterKen Oursler Jr.

One of the great things about the Paleo "community" is how each of the major blogs (Marks; Daily Apple, Track Your Plaque, Animal Pharm, Hyperlipid, Nephropal, FatHead, Free the Animal and PaNu) )brings something unique to the table.

Aside from Kurt's excellent analysis and opinion, it appears that he has a gift for wordsmithing accurate, concise and poignant observations. For example:

My view is plant worship is the politically correct residual of mainstream health food thought that is still infecting the paleo/primal world.

November 12, 2009 | Unregistered CommenterPatrik

"The Vitamin C canard has been refuted on virtually every Paleo-type site out there."

I've read this on a few blogs, but not the explanation...Can anyone point me in the right direction, or give me a quick summary of why C is not necessary (preventing scurvy, immune response)...I'm not lazy, just have 3 kids and spend most computer time working on getting the sugar and processed carbs out of our schools.

I have read raw organs have some C (maybe enough if RDA is overstated?), but we won't be eating much of those! Are there other animal sources of C?


November 12, 2009 | Unregistered Commentersandra


Taubes touches on the vitamin C issue in GCBC. Here is his summary (p325-326):

"In other words, there is significant reason to believe that the key factor determining the level of vitamin C in our cells and tissues is not how much or little we happen to be consuming in our diet, but whether the starches or refined carbohydrates in our diet serve to flush vitamin C out of our system, while simultaneously inhibiting the use of what vitamin C we do have. We might get scurvy because we don`t faithfully eat our fruits and vegetables, but it`s not the absence of fruits and vegetables that causes the scurvy; it`s the presence of refined carbohydrates."

He also talks about Vilhjalmur Stefansson, who went for years at a time without fruits and veggies, with no scurvy.

Dr. Harris:

Great post, great blog. A couple questions:

At 70% fat, do you use dairy? If not, what sources of fat do you rely on?

Also, a couple posts back you mentioned doing one on Kwasniewski`s Optimal Diet. Any chance that might be coming soon?




I hate counting measuring and weighing, so the 70% is a guess. There is nothing in the world that tastes better to me than whole cream. I drink it straight. I also eat a large variety of hard cheeses. I would eat more fermented dairy (yogurt) if I could buy it easily locally.

There is a brief post already on Kwasniewski but no time for a full review - too much other stuff.

November 12, 2009 | Unregistered CommenterDave McEachern

@sandra: It is my understanding, on a high meat/very low/zero carb diet, that uric acid performs many of the metabolic functions of vitamin C. I have been eating this way for nearly two years (no fruit or veg) and have not had any issues with vitamin C deficiency.

November 13, 2009 | Unregistered CommenterAlex Thorn


Barry Groves was asked on the rawpaleo yahoo group some time ago about why certain species, such as primates, have lost the ability to synthesize vitamin c. Here is his answer:

"There are a couple of possible reasons. Firstly, a Vit C is used in
the body mainly to metabolise carbs, and we are a carnivorous species.
If we eat only a natural carnivore diet, we have very little need of
Vit C.

And secondly, we don't need to be able to make Vit C as we can already
get enough from foods. Although we are told that Vit C only comes from
fruit and other plant material, in fact all foods from animal sources
also do. For example, weight for weight, liver contains 4 times as
much vitamin C as apples or pears. Adrenals are even better -- although
not so easy to come by."

November 13, 2009 | Unregistered CommenterSatya

Thanks for the responses on vitamin C... I have probably been eating too much fruit out of false concern on this.

November 14, 2009 | Unregistered Commentersandra

Yes, Taubes does cover the vitamin C issue well in his book.

One point he made was that the vitamin C molecule is very close structurally to the glucose molecule, so the vitamin C and glucose molecules are both fighting for uptake into the cells and obviously glucose will win out when blood sugar levels are high. Glucose essentially regulates how much vitamin C is taken up by the cells. So as you increase your glucose levels, your vitamin C levels decrease.

He used this argument when talking about scurvy; it's not that it was the absence of fruits and veggies that caused scurvy, but the presence of high amounts of carbs.

Good lord, I'm not a scientist, so if anybody can jump in and save me from this piss-poor explanation, please do so. :-) Hopefully you get the drift.

November 16, 2009 | Unregistered CommenterMolly

i was wondering what your thoughts are on A1 and A2 proteins in dairy products. Apparently A1 proteins are the result of a nw mutation and are harmful....what do you think?

November 17, 2009 | Unregistered Commenterreamz

Thank you for an interesting blog, mr. Harris.

I am of the same opinion regarding "magic" vegetable compounds. But since you asked, what do you make of this study? Chocolate flavanols could protect the skin from UV-light:

KGH: So maybe if you eat a lot of chocolate you will be become D deficient?

November 18, 2009 | Unregistered CommenterKowalski

Oh my. I've just spent, what? three hours on this blog. Holy Moly, but you have a logical mind. What an absolute pleasure to see it at work!


Thank you for your kind words, Joanne.

November 23, 2009 | Unregistered CommenterJoanne

Hah, I like that answer. But what about curcumin? That sure seems magical?

And I'm not asking to disagree, I'm just playing devil's advocate to myself. For some reason people who go on about magical plant compounds irritate me, and I could use a tried way to refute their claims. Most of the studies are epidemiological, some experiments just bad science, but since I haven't read "all" of the studies, there's always a nagging suspicion I'm missing out on something major. This is a good post in that regard. (Some people actually seem to think that say, bruising easily is caused by a citrus fruit deficiency...) I'd really appreciate your feedback on the curcumin matter!

November 24, 2009 | Unregistered CommenterKowalski
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