The problem I have with being vegetarian is that you can't prove that it's actually healthier, because the current state of dietary science is pretty poor.
Even if you could, you would also need to explain all of the evolutionary problems that could come from some humans going vegetarian while others don't.
What if being vegetarian makes you smaller and weaker physically (perhaps the case in some vegetarian countries now). If you had the answer, and it was clear a diet consisting of vegetables causes reduction in physical size, then I have to ask:
Would you want your kids to be shorter and physically weaker than you are?
Even if you could, you would also need to explain all of the evolutionary problems that could come from some humans going vegetarian while others don't.
What if being vegetarian makes you smaller and weaker physically (perhaps the case in some vegetarian countries now). If you had the answer, and it was clear a diet consisting of vegetables causes reduction in physical size, then I have to ask:
Would you want your kids to be shorter and physically weaker than you are?