You may want to look up a couple things:
1. Historical life expectancy trends
2. Theory of evolution
That is, if you "believe in" science (which, I'll tip you: it is not a belief).
Veganism is healthy.
Which is why two vegan youtubers, with pretty big following, quit this cult. One of which was caught red handed, while still claiming to be vegan.
Just look at vegans, they look so healthy.