One does not need to eat meat in order to be healthy. There are hundreds of millions of vegetarians world wide; that's a hell of a sample size and yet there is

One does not need to eat meat in order to be healthy. There are hundreds of millions of vegetarians world wide; that's a hell of a sample size and yet there is a remarkable lack of evidence to support the claim that they are all unhealthy. So really, what's the problem with replacing meat?