Why Do Some People Do Well as Vegans and Vegetarians? (Clues From the Magical World of Genetics)


Do you ever wonder why some people seem to do just fine as vegans and vegetarians, while others turn into quivering heaps of deficiency and woe? Does it bug you that the common rationale is either that 1) the “feelin’ good” vegs are either deluding themselves or cheating, or 2) the folks who crash and burn were just doing it wrong?


So I wrote a guest post looking at why people respond differently to plant-based diets.

Because genetics. And microbes. Yay!

Go take a look-see if this topic interests you:

4 Reasons Why Some People Do Well as Vegans (While Others Fail Miserably)

(Also, I promise—promise—that Low Fat Part 2 is still on its way. One day, when you’re least expecting it, you will wake up and make your scrambled eggs or green smoothie or organic grass-fed lightly seasoned caribou bone broth, check your inbox, and then hate me because I gave you thousands of words you don’t really have time to read. I’m sorry in advance and I love you all.)



  1. Hi Denise,

    Thanks for your email. I will read your article with great interest, like I did with your book, articles and speeches posted online. So much so that I regularly quoted you in my (Dutch) book: Weet wat je eet (Know what you eat) – Healthy eating based on the oldest knowledge and the newest science.

    It has a chapter on Weston Price and with 60 pages of footnotes (online to not bother the reader) and it has been well received. Thanks again for your input in several chapters.

    Best, Daan de Wit, Amsterdam, the Netherlands


  2. So how would the average vegan know, before some malady occurred, that they were deficient in an enzyme or gut bug? My hospice patient died of diabetes and dementia.

    The article has an upbeat vibe, but I wonder how much intervention/ monitoring is needed to give reliable and effectual advice? Is there reliable cost effective testing available? Would one get this information from discussion boards or magazines?

    Vegans may well be better nourished than my grandchildren, who at present consume cereals, mac&cheese and Spagetios and chicken nuggets. Hopefully they will develop a hunger for real food.


    1. A vegan would know in the same way that your children will know when they develop real hunger.

      The majority of vegans are getting signs that they either ignore or consciously choose not to address:
      * True Hunger – having to eat numerous times per day chasing satiety.
      * Minor annoyances and physical clues: cold, weakness, fatigue, pains (teeth, joints), skin issues,…

      In most cases, veganism is tied to ethics which unfortunately forces them to put the wellbeing of animals above their own health.

  3. You’re the best, Denise. Most objective, trusted writer on food, with no fear-based ideas, no ideology to sell. Right up there with Michael Pollan!

  4. Funny that this notification came in just as I reading your post on Authority Nutrition. Please be sure to take a look at my Disqus comment there. And thank you again!

  5. Interesting read as usual. I guess gut bacteria is really gaining traction in nutritional studies. Looking forward to your next post!

    1. I doubt it. She couldn’t hold her own in attempting to refute T Colin Campbell’s ‘China Study’. Any vegan with an interest in the health side of plant based eating would know her words are a sham.

  6. Denise: Thanks again for another fine piece of work. Plus two completely useless but fun factoids: carotenemia and lycopenemia! We thought we had enough diseases to worry about already. Bless you. Looking forward to Low Fat part two.

  7. Thank you! This can explain why my year as a vegan was totally crap (I have ms, so it was a health experiment), the relief I felt in my body when I went back to being an omnivore was palpable.

  8. I’m wondering if you have run across any information about genetic anomalies preventing optimal use of other vitamins, such as D3.

    > Raw Food SOS > October 20, 2016 at 1:34 PM > neisy posted: “HEY GUYS. Do you ever wonder why some people seem to do > just fine as vegans and vegetarians, while others turn into quivering > heaps of deficiency and woe? Does it bug you that the common rationale > is either that 1) the “feelin’ good” vegs are either delu” >

  9. I’ve learned several new things here, but what is most interesting to me is that we have the capacity to convert K1 to K2. Thought it was only ruminants who could do that. This is good news. I have eaten natto intermittently over the past two or three years, but recently threw it all out. My tummy simply doesn’t like legumes. Plus I find it difficult to get past the taste sensors; foul stuff.

  10. My foray into veganism several years ago was fairly spectacularly bad. I went vegetarian first so as to ease the transition but things started going south pretty quickly. As my reason for doing so was based primarily on the oft touted health benefits rather than any ethical or environmental considerations, feeling worse than when I was an omnivore was entirely unacceptable. I went from rarely getting sick to catching every cold doing the rounds. Interestingly, my 23andme results suggest that I am one of those low responders to beta carotene so that could explain a lot. Genetics. Fascinating, right?

  11. Denise

    Thoughtful insights as usual.

    Regarding Vitamin A and its conversion, I feel other nutrients need conversions too from plant to be able to be used by the body.

    One of these I can think of is ALA omega 3 fatty acid, that needs conversion to EPA and DHA.

    These conversions require enzymes and other components. If a body type are lacking these, it makes the conversion difficult and hence being on a vegan/vegetarian diet is not ideal.

  12. Hey Denise,

    This should be more widely distributed on those “forums” you mentioned.

    Also, what is the rationale behind coconut water? And is there a specific brand you’d recommend?

  13. Just came to express my gratitude about providing the scientific means to destroy some of the latest annoying pseudo scienctific vegan bullshitism. it was a great relief to read the basis for destruction of their religious book

  14. Recently I went to the dentist. As I was locking my bike to the handicap pole (usually the only thing available), a couple parked in the space. They came in after me and sat down, and looked about 20 years younger than I. Both were using canes. After the man went in for his torture, the woman and I got to talking. Turns out she has MS, and is a vegan. I told her about Dr. Wahls and how she had reversed her MS through dietary changes. I’ve wondered ever since which came first for her, MS or veganism. She said she followed Dr. McDougall’s way of eating. She didn’t seem militant about it. I hope I planted a seed. I talked to her about the fat-soluble vitamins and the importance of eating eggs.

  15. Thanks for sharing information. I am really searching a lot for things about veganism and stuff.
    There’s so much things to take into account that makes things confusing sometimes, but this is nice information. Thanks a lot.

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