Not replying to the comment being quoted, just clicked reply because I can't anywhere else on the page.
The misinformation in the replies on this thread are alarming. Additionally, the entire thread is based on a phenomenon that is not even happening. The number of vegans worldwide is growing, as evidenced by the finding that since 2016 there was a 700% increase in the number of vegans in the UK. I'm sure if you look at statistics from around the world you'll see a similar trend. Also, the fact that a few youtubers quit veganism doesn't mean that it's bad-- by the same logic, the youtubers who go vegan from an omnivorous diet would be doing the same thing, which would mean that an omnivorous diet is bad by the logic in the original post.
As for nutrient deficiencies, the following study (absolutely huge study size and study length) found that vegans were deficient in three nutrients while omnivores were deficient in seven. So, which diet leads to more deficiency?
For the concerns over iron, I'll paste the following excerpt from nutritionfacts.org (all peer-reviewed research, non-profit association run by a non-vegan):
"What does meat contain that may raise risk of premature death? One possibility is heme iron, the form of iron found predominantly in blood and muscle. Because iron can generate cancer-causing free radicals by acting as a pro-oxidant, iron is like a double-edged sword—too little of it and you risk anemia, too much and you may increase cancer and heart disease risk.
Our body has no specific mechanism to rid itself of excess iron. If we don’t have enough, our intestines begin boosting iron absorption; if we have too much, absorption is decreased. But this system only works effectively with the non-heme iron found predominantly in plant foods. Once a sufficient amount of iron is in our blood, our body is about five times more effective at blocking absorption of excess iron from plant foods than from animal foods. This may be why heme iron is associated with cancer and heart disease risk, and higher risk of diabetes, but non-heme iron is not.
Compared with people who eat meat, vegetarians tend to consume more iron (and more of most nutrients), but since the iron in plants is not absorbed as efficiently as the heme iron in meat, about 1 in 30 U.S. menstruating women may lose more iron than they take in, which can lead to anemia. Women who eat plant-based diets don’t appear to have higher iron deficiency anemia rates than women eating a lot of meat, but all women of childbearing age should ensure adequate iron intake.
Those diagnosed with iron deficiency should talk with their doctors about first trying to treat it with diet, as iron supplements have been shown to increase oxidative stress. The healthiest iron sources are whole grains, legumes, nuts, seeds, dried fruits, and green, leafy vegetables, which can be paired at the same meal with vitamin C-rich foods such as citrus, bell peppers, broccoli, and tropical fruits to boost iron absorption."
https://nutritionfacts.org/topics/iron/
Protein is nearly impossible to be deficient in so long as you're getting enough calories. The WHO recommends 5% of daily caloric intake be protein, so you can easily reach that recommendation and be fine. source:
https://www.drmcdougall.com/misc/2007nl/apr/protein.htm
Also, every body is NOT different. We are all HOMO SAPIENS with the SAME digestive tract, organs, etc. Individual variation does not exist in the capacity that is mentioned in the comments before me. What is different is the gut biome, which is determined by the food you eat. Your gut can adjust to digesting eating a meat-based diet; however, it doesn't mean that you won't incur the risks of eating a meat-based diet. Our ancestral diet is one of starches, legumes, vegetables, fruits, and at times a LITTLE meat. For a look at what a population of our ancestors may eat, look no further than the Okinawans, or any hunter-gatherer population. You will see that animals and animal products are an extremely low percentage of the diet, for the simple reason that meat is very hard to get. The bulk of our ancestral diet and thereby OUR diet since we haven't evolved that much in the course of 100000 years, is made up of starches, legumes , vegetables, grains, and fruits.
Thanks S. Canaday for posting!