Seems mad to base one's diet on a philosophy rather what one's body needs. To survive, vegans and vegetarians have to use commercial suppliments produced only by a high technology. Vegans are especially vulnerable since they don't eat dairy products and dairy products are necessary, with grains and legumes, to balance the proportions of four essential amino acids needed to make a vegetarian protein. Animal tissue is complete and perfect without hassle or high technology.
Human beings started off hunter/gatherers. Uncovered remains of hunter/gatherers yield strong bones, healthy and complete sets of teeth. Uncovered remains of later agricultural phases yield the opposite.
Every thing known about the human body points to the fact that we are omnivours designed to get our protein from animal muscle tissue. You keep trying to combine those amino acids; I'll use that which is already perfect.
I suggest that the primary nutritional challenge to Americans includes a diet of excessive fats and protein. Seems like I see a lot more deconditioned fat people awaiting heart attacks than ashen faced vegetarians collapsing from meat deprivation. Of course I live in the heart attack center of the U.S., and it is abundantly clear, sad to say.