Many people make the mistake of choosing a fragment and building a total way of life around it. Vegetarianism is one of them. Dietetic laws are only part of the laws laid down by nature to ensure healthy, happy and harmonious living. Even in diet there are other things that are far more important than an exclusive vegetarian diet for superior nutrition of the human individual. Unless these other conditions are fulfilled, superior nutrition will not result.
Most vegetarians are so because of ethical reasons.
Ahimsa, harmlessness is the creed of vegetarians. So far so good, and that is what it should be. But, putting aside ethical and moral values re animals and other creatures, most vegetarians haven't a clue as to their own welfare and wellbeing. Otherwise the millions of vegetarians all over the world would be brimming with health. Alas, such is not the case.