I’m sure the evidence is out there, but I have so many first hand experiences of people having health issues from vegan diets, that I’m not terribly motivated to go out and look for it.
When I was in high school, I had a few friends who tried to go vegan. One fainted in the shower, another fainted during track and field, one was falling asleep in class all the time. As soon as they went back to their normal diet, everything went back to normal for them. In first year university, a friend lost 30lbs and became very emaciated from their vegan diet.
You could say “they were doing vegan diets wrong” and I would agree. That’s the point. It’s extremely hard to do vegan diets “right”.
Ok, one more anecdote for you: I've been vegan for about five years, for ethical reasons. (Which is to say, I basically have eaten a similar diet to what I did before, only vegan -- so vegan ice cream in lieu of dairy ice cream, sofritas Chipotle burritos rather than steak Chipotle burritos, Beyond burgers rather than cow burgers.) I've taken the occasional multivitamin but nothing special -- I get B12 and all that from fortified soy milk and other foods. I'm physically larger -- at six foot, my weight has ranged from 202 to 185 lbs as a vegan rather than 185 to 170 lbs as it did when I was omnivorous -- and run (my main form of exercise) faster, farther, and more frequently than when I ate omnivorously (I.e. it's not that I've gotten fat). Blood work has always been perfect, recovery times much lower, energy levels fine, etc. Zero health issues.
Your friends were doing it wrong. Probably, they were eating nothing but salads, or stacking dietary restrictions (e.g. gluten-free or raw).
I know many many, very healthy plant based people and athletes. I regularly run ultramarathons and I cycle 30 miles a day to work (2000 ft of climbing) and I'm plant based.
Would you say I'm doing it right? I don't do anything especially difficult with my diet.
When I was in high school, I had a few friends who tried to go vegan. One fainted in the shower, another fainted during track and field, one was falling asleep in class all the time. As soon as they went back to their normal diet, everything went back to normal for them. In first year university, a friend lost 30lbs and became very emaciated from their vegan diet.
You could say “they were doing vegan diets wrong” and I would agree. That’s the point. It’s extremely hard to do vegan diets “right”.