Response to Mark Sisson’s assertion that vegetables are necessary for health

Mark Sisson is the author of The Primal Blueprint, and the blog Mark’s Daily Apple. His blog is a great reference, and I like his work. However, I take exception to the article he posted this week entitled Do You Really Need to Eat Vegetables to Be Healthy?

Although he admits at the end that you probably don’t need them, this admission has much less prominence than the section near the top where he says

“Yes. Yes, you do. Maybe not a huge amount, necessarily. But you do need some.”

Then he goes on to make some arguments for eating vegetables that I’d like to address.

  1. Modern Hunter-Gatherer diets: First he argues that three of the four known modern hunter-gatherers that are purported to be carnivorous (Inuit, Masai, and Sami — leaving out Plains Indians) weren’t actually. I don’t think that’s really settled, but more importantly it doesn’t matter. Even if it were true that all modern primarily carnivorous societies ate some plants, that doesn’t and couldn’t prove we need them.

  2. Plants as medicine: A second argument that is weaved throughout the post is that plants have medicinal compounds, and therefore should be eaten. But this doesn’t make sense. This is an argument for growing plants and extracting compounds so that we can isolate and concentrate medicine into useful portions, while removing the toxins that accompany the source. It’s no argument for taking daily minute doses of medicine along with a bunch of other random stuff that grew with it. I’ve addressed that more fully in the post Biochemical Warfare

  3. Missing nutrients: Another argument is about getting some particular nutrients. It is argued that modern meat may be depleted of some minerals and vitamins that are dependent on the diet of the animal. That is, there are wild plants that are part of the diet of wild animals, that they use to make vitamins that we then eat, and modern meat may be inadequate. This may well be true, but insofar as it is, it does not make a convincing argument for eating those plants ourselves, along with whatever other matter they contain, any more than it argues for taking supplements. Even if modern meat is insufficient, that is no argument for eating vegetables. Moreover, a similar argument is sometimes made about plant vitamin and mineral content due to soil depletion, so eating plants may not even solve it.

    (I’m ignoring the part of that section that suggests we only need plants if we refuse to eat offal or reserve the cooking water, since they support the ability to get those nutrients from meat.)

  4. Feeding gut bacteria: Finally, the argument is made that we should eat fermentable fiber to feed our gut bacteria. Although there is much interesting research into the role of gut bacteria in health, it is far from conclusive what the best health practice is with respect to them.

    As a researcher aptly pointed out in an editorial last year:

    “This considerable increase in the number of [publications devoted to the study of digestive microbiota] has generated assumptions and speculations on the role of digestive microbiota in human and animal health are likely far beyond our current knowledge.” — Didier Raoult. Digestive microbiota and its influence on health: Facts and myths. Microbial Pathogenesis. 2013 Aug-Sep;61-62:A1. doi: 10.1016/j.micpath.2013.05.008. Epub 2013 May 27.

In sum, I respectfully disagree with Mark Sisson’s statement that the question “Do You Really Need to Eat Vegetables to Be Healthy” can be answered definitively, let alone with a “yes”.

I am more inclined to agree with the points he makes along the way: that if you do not eat vegetables, then you should consider eating offal, drinking broth, eating wild game, or taking supplements. In fact, I think those are worth consideration even if you do eat vegetables.

41 replies
  1. Roseanna Smith
    Roseanna Smith says:

    This is a great response to a post that was (uncharacteristically, I think) full of unexamined popular sentiment. The thing that bothered me the most in his post was the underlying assumption that a random assortment of plant matter could somehow fill in specific (allegedly) missing nutrients, have beneficial medicinal effects, and "improve" your gut microbiome. Without even knowing what nutrients you might be missing, how could you possibly select a plant food that would deliver them? And really — just randomly raid the medicine cabinet daily, and you're bound to take something that'll do you some good? That seems to be his startling implication. And don't even get me started on the gut biome business.

    Thanks for taking this on.

  2. Kim
    Kim says:

    I have a lot of weight to lose and T2 diabetes and want to do a ketogenic (close to meat only) diet but I am confused because of the following comments were made on Richard Nicholey's blog Free the Animal (not vegetarian). Can you comment on this? I have read Bernstein's book in the past and have followed his protocol in the past too, but had never heard this.

    Dr. Bernstein’s patients, who follow a 30 total carb (not net carb) per day diet which is ipso facto ketogenic. Bernstein actually says (and it’s straight from the horse’s mouth) that 100% of his patients have autoimmuen diseases, 100% have psoriases, 90% are hypothyroid, 85% have Raynaud’s. About 25% have severe immune deficiency syndromes like CVID, which Bernstein himself has. How could all this be related to ketosis? The T memory cells that are affected when your thymus is put under environmental stress, as in ketosis. If those cells lose their function, your immuen system can go haywire, as they learn to distinguish between self and antigens. Not much has been written about it and low-carb researchers like Volek, Attia, Westman have all missed this. These nitwits only looked at lipids and blodd sugar and declared ketosis is safe. Many of these guys have their WBCs declining from the 7s to the 3s and 4s, a sign of immune deficiency and leukocytopenia. This is what’s gonna destroy the LC world. In about 5 years, there will be no one in the LC world whose reputation is not in tatters. It’s not a matter of discomfort, subclinical/euthyroid symptoms or just cold hands. These are really sick and becoming sick, and became snared by a dangerous trap called ketosis.

    I also know a very prominent guru (referring to above) whose patient population have an autoimmunity rate of 1000%; that’s 100%. He’s said that 90% of his patients have Raynaud’s, and 90% are hypothyroid (low T3). He prescribes cytomel and T3 medication freely. But do you know the other side of the coin? About 1/3 of his patients have a serious immune condition called CVID (Common variable immunodeficiency). Another 1/2 have a singular immunoglobulin deficiency which makes flu and pneumonia shots pretty much ineffective. Sudden food allergies, unexplained allergies to airborne particles, dust mites, and indoor materials are features of some of these conditions. These allergies show up all of a sudden and you start sniffling around constantly.”

  3. daryl broussard
    daryl broussard says:

    Soooo….. what about all the folks eating VLC/ZC, that have done so for years, and have none of that? And are you saying that it's soley being in ketosis that does those things? Even if it did, quite a few of the VLC/ZC folks probably are NOT in ketosis, as they take in enough protein to effectively prevent that.

    Amber, awesome work.

  4. Nyker
    Nyker says:


    Great post, but at the end you write, "I am more inclined to agree with the points he makes along the way: that if you do not eat vegetables, then you should consider eating offal, drinking broth, eating wild game, or taking supplements."

    In other words, you agree that eating fatty meat alone is not sufficient. If not by eating vegetables, then an exclusive meat-eater should supplement with vitamins or eat those other things mentioned.

    I realize that definitive statements require extensive research, which means that I will merely relate my experience of being an exclusive meat-eater for the past five years. During that time, I never once ate vegetables, fruits, anything from the plant world, and did not take any supplements. Not only is my lipid profile vastly improved, but all markers of health are better. While you are inclined to agree with Mark Apple, I am inclined to disagree. That inclination is based on my experience, of which I am 100% certain. I am not relying on others research. And, yes, I realize that a study of one does not prove a point.

  5. Kim
    Kim says:

    It wasn't me that said it. I copied someone else's comments off the site. I have practiced vlc and zc before without those side affects (that I know of). I do have low thyroid but can't say where or when I actually started having low thyroid.

  6. Kim
    Kim says:

    There are a lot of comments on that thread (link posted above), but I only copies a couple of parts of it. I am just confused as I don't want to put myself in further deteriorating health if that was the case. And yes, they are insinuating that being in ketosis is what does those things. Someone also insinuated that Dr. Bernstein knows about all these problems and has purposely hidden them.

  7. Brendan Watson
    Brendan Watson says:

    All I can say is tha I dont need to eat any. And I dont. Never been in better health in my entire adult life. My research on me far outweighs anything, anyone else can tell me.

  8. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    Dear Kim,

    I am aware of Richard Nikoley's current opinions on this topic. That quote contains myths, rumours, and opinions, all stated as fact. I could go through it point by point and tell you why I find each one unconvincing, as I have done with Mark Sisson's. However, I have deliberately chosen not to thus far, because I don't think that kind of rhetoric warrants an objective response.

    I can't guarantee that you will thrive on a ketogenic, mostly meat diet, but in my opinion, the odds are strongly in your favour.

  9. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    Haha. Zooko immediately told me my last sentence could be taken that way. (Good call, Zooko.)

    What I meant to say was: if you are worried about it, those are good sources of nutrients, and whether or not you eat vegetables, they are worth consideration for their nutrient value.

  10. Kim
    Kim says:

    Thanks Amber. I have done well on mostly meat for as long as a year before the cravings for bad carbs snuck up on me. Basically, life just overwhelmed me and I ate some carbs and then I was off to the races. I believe I will try it again. Even though I am on metformin and my fasting bs was getting lower, I still could not get it below 100. The last few weeks I lowered my carbs even further eating just meat at most meals and it finally got below 100. First time below 100 in over a year.

  11. Nyker
    Nyker says:

    OK, thank you for clearing that up.

    Just a bit more personal info to complete the picture, I do not eat offal or wild game, but, on rare occasion, I have homemade chicken soup. I'm not convinced that any of those are necessary, but I have no way of proving that. If I'm wrong, then I'll pay the price sometime down the road. It's a risk I'm willing to take given the fact that my health is so good and I would probably have noticed a deficiency if those additional foods were necessary. It's like the supposed need of Vitamin C to avoid scurry. I have not ingested any Vitamin C for five years and, yet, I have all my teeth and I'm still alive.

    My posting is not meant as a criticism, but just as a real-life example of someone who eats only meat and is doing fine. Actually, more than fine!

  12. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    As a 4+ year carnivore, I'm not particularly surprised about your experience. Thank you for sharing it.

    I have taken supplements on and off over the years, so I can't know what impact they have had. Nor have I been utterly without plant ingestion over this time, although the amount is minute. Nonetheless, I find it hard to believe that a bit of daikon with sashimi once every few months, or the particles in the coffee I drink regularly is making a critical difference.

    More importantly, when I ate a very low carb diet that included vegetables, I was drastically less healthy.

  13. raphi
    raphi says:

    @L. Amber Wilcox-O'Hearn

    I enjoyed your blog posts I've read so far.

    Your way of eating is 'extreme' depending on ones look-out point – but it's certainly more 'normal' than eating modern processed food.

    I was wondering if you thought it worth your time to look at how traditional populations on high-carb diets fared well according to available anthropological data (as per Lindbergs Melanesian population studies for example).
    This is not a 'which is better' question – more of a request for your opinion on such a different way of eating.


  14. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    Thank you, raphi. I do not think that modern hunter gathers are good representatives of pre-agriculture, since they have had to adapt to the extinction of the very fatty mega-fauna that may have been our mainstay. That said, I do think the fact that the high-carb examples of modern HGs also lack many modern diseases is interesting, and poses important questions.

  15. raphi
    raphi says:

    "I do not think that modern hunter gathers are good representatives of pre-agriculture" – that may well be true. I tend to agree that the balance of anthropological, biochemical & climatological evidence suggests a heavier emphasis on fat out of the 3 macros.

    However, these traditional populations remain – they're strong empirical evidence of humans not only surviving but thriving on high-carb diets. Chances are, if they could live so, then there likely were others living on similar diets even in the pre-agricultural era…I find it interesting and hard to ignore (in the interest of science of course!).

    I understand the concept behind metabolic flexibility & see it as a potential explanation – however, maybe what's missing are the added ideas of low environmental toxicity + significant intermittent fasting (i.e. forced punctuated ketosis even on an otherwise carby diet)…?

    PS: my blood ketones this morning were 1.6mmol/L – does that count as "proof" that I'm a fellow 'fat' afficionado? 😉

  16. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    I too have heard the rumour that Kitavans intermittently fast, if that's what your referring to. They are a funny case for many reasons, not least of which is that they smoke, and yet no one (AFAIK) goes around saying "Look, you can smoke and be healthy, the Kitavans do it."

    You don't need to be in ketosis for me to consider your points, but it does give me an idea of what assumptions we share. ☺

  17. raphi
    raphi says:

    Not sure what you mean by rumor. I'm making the (I think, safe assumption) that it's extremely unlikely that non-modern/non-industrialized societies had a '3 meals a day' ethos in addition to the fact that daily life/climate/tribalism etc., easily got in the way of such regimented eating patterns (so automatically calling for some degree of intermittent or complete fasting).

  18. Alan2102
    Alan2102 says:

    "Bernstein actually says (and it’s straight from the horse’s mouth) that 100% of his patients have autoimmuen diseases"

    Anyone familiar with the historical writings on low-carb dieting will recall Dr Wolfgang Lutz, one of the true pioneers in this area, and his book "Life Without Bread" (in German; published in English with another title which escapes me at this moment). He had several decades of personal (very strict low-carbing) and clinical experience with the diet, treating thousands of patients with it. One of his observations was that his dieters frequently developed (mild) autoimmune phenomena and required small doses of corticosteroids to control same. He attributed this, I believe, to the notable "anti-stress" effects of the diet, presumably damping adrenal function.

  19. Michael Frederik
    Michael Frederik says:

    On the point of offal above, I don't find that such an unfortunate word. But in any case, I'd point out that the Joe Beef boys now call tenderloin the "postmodern offal". And another quote from them: "In a hypothetical dystopian foodist nation, animals will be bred in humane ways to produce more spleens, livers, and guts than loins and legs."

  20. Esmée La Fleur
    Esmée La Fleur says:

    Thanks for sharing your experience, Nyker! What you say about vitamin C is very interesting. I am curious to know how you prepare your meat. It seems to me that if you eat some of it rare or raw that it would contain vitamin C?

  21. Esmée La Fleur
    Esmée La Fleur says:

    Rap hi, have you read "Health and the Rise of Civilization" by the Nutritional Anthropologist Mark Nathan Cohen? He examines the health of the bones from two groups of Native Americans who lived in the same location in Kentucky 800 years apart. The older group was strictly hunter-gatherer, while the younger group was more of a farming community. The bones of the older group showed vastly superior health.

  22. Esmée La Fleur
    Esmée La Fleur says:

    The most interesting thing for me in this whole discussion about the value of including vegetables and other plant matter in the diet is that I never once, until now, questioned the assumption that it is indeed necessary! There are so many "givens" that we all seem to take for granted without any evidence to back them up. Thanks for challenging the status quo.

  23. Esmée La Fleur
    Esmée La Fleur says:

    Another point worth mentioning, I believe, is that fact that there are almost no plant foods in our markets today that look or taste anything like the plant foods our Paleo ancestors would have encountered in their wanderings. All modern fruits and vegetables have been hybridized to reduce the toxic (biochemical warfare) components and increase the sugar content to make them more palatable. I wonder how many ancient, natural versions of our modern plant foods would have even been edible? They must have been quite a bit more bitter than anything we have tasted. Wild berries might be the one exception. And we certainly did not grow our big brains on a plant food diet! Knowing this, makes the idea of veganism patently absurd (and I spent more than a decade as a vegan, unfortunately).

  24. raphi
    raphi says:

    I've heard of it but have not read it. The summary on Amazon frames his central argument as an argument against the classical notion which regards non-civilised groups as hungry, in poor health and enduring short, brutish lives. I think this caricature is entirely wrong although famine, infections and high infant mortality were very real features of our existence. This kind of anthropological case-study is very valuable (& rare!) and is fantastic in helping form good hypotheses that can then be tested through molecular biology, in clinics and in controlled studies.

    Have you read it? Do you know if the author makes any diet recommendations or observations based on his work?

  25. raphi
    raphi says:

    Your remarks about the differences between pre-agricultural and agricultural foods are well taken. However, I'd caution against 2 notions that often spring from that line of thinking:
    1) if it was good for us then, it MUST be good for us now. This ignores the all-important variable called 'context'.
    2) if we didn't encounter a certain food during the Palaeolithic then we cannot be adapted to it. This is false because food properties to which we are adapted to can be combined in novels that may or may not be evolutionarily concordant with our biology.

  26. L. Amber Wilcox-O'Hearn
    L. Amber Wilcox-O'Hearn says:

    Good point. That reminds me of Kurt Harris arguing for butter. Essentially he said that while it is true we probably had little access to butter, it still has an evolutionarily favourable chemical make up. Looking just now, I see that the website ( is gone, which is a real tragedy in my view. However, at least some of it is recoverable from the wayback machine. I know what I'm doing this morning…

  27. raphi
    raphi says:

    Yes he's an interesting chap. Kresser mentioned being in an email back-&-forth with him and linked to a recent piece of his – too bad it led to a broken link!

    To my mind it's quite simple, actually: considering how much we don't know, evolutionary theory is our best and arguably only decent starting point (or framework) to think about health. All of the subsequent hypotheses that arise from it should be tested as rigorously as possible with the best that modern science has to offer…if we want to validate these ideas scientifically, that is. I think we should. When this isn't feasible or possible, falling back on the "least bad" idea often means following the hints of evolutionary biology &/or applying the precautionary principle (itself a result of thinking about our evolutionary past!).

    Darwin's ideas still have much to give and I fear the "Paleo movement" is becoming a worse and worse popular vessel for them. Fingers crossed!

  28. Esmée La Fleur
    Esmée La Fleur says:

    It is an academic test that I read in college when I was getting my undergraduate degree in Anthroplogy, which was over 20 years ago now. I need to read it again. What I remember is that his discoveries basically support was Weston A. Price observed in his examination of native peoples eating traditional or non-traditional diets. Those who included more animal source foods had better bone structure and were healthier. I don't remember if Cohen makes any recommendations for us modern day humans directly, but the implications were certainly there.

  29. Esmée La Fleur
    Esmée La Fleur says:

    Yes, Raphi, many people have clearly "adapted" to more modern foods and do just fine with them. I think it may depend on how far removed we are from our ancestral diets. It seems that people of Northern European ancestry or Native American ancestory are far less adapted to food high in carbohydrate than people whose ancestors hale from the Fertile Crescent and grain-growing regions of our planet.

  30. raphi
    raphi says:

    Cool. Your anthropological insights will be called upon 😀

    Weston A. Price has done more to advance nutrition science than many modern 'authorities' who write a lot yet say very little **

    ** to be fair, SG's work is interesting and once can get a decent value from it. Problem is, too many of his premises & extrapolations ignore so much basic biology that I cannot rely on him. After all, he could have graciously embraced what (gasp!) science JOURNALIST Gary Taubes did for him – i.e., show him that it's not just about calories – but instead he doubled-down. Too bad.

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