Photo credit: woodleywonderworks While certainly a topic of perennial and vehement debate, most nutritionists and studies agree that the human consumption of animal meat is part of a balanced diet. The proteins found in animal meat and fat contain all the essential amino acids the body needs to grow, and are often more easily assimilated by the body than proteins found in a vegetarian diet. Dr Weston Price, a leading researcher of traditional diets who conducted vast studies of indigenous tribes in the 1930s, found that animal meat and fat was the singular most important dietary component among the tribes he studied, inhabiting all extremes of conditions, from the coldest to the warmest regions on earth.
However, it is absolutely possible to obtain all the necessary nutritional elements the body needs from a vegetarian diet. The problem is that many people choose to become vegetarians without spending time studying how to be a healthy vegetarian. Because it is harder to obtain all the necessary vitamins, minerals and proteins the body needs from a non-meat diet, it is important that vegetarians have a strong grasp of the right foods they must eat, as well as the quantity and combination of foods, in order to maintain a healthy, balanced nutritional composition.
Healthy vegetarians make a daily effort to monitor their nutritional intake, particularly in regard to certain vitamins that are more easily found in animal meat, most notably Vitamin A, Vitamin D, Calcium, Zinc, Riboflavin, Iron and especially Vitamin B-12. The right combination of foods is required so that the vitamins are activated and ingested in the right amounts. From a Chinese medicine perspective, which highly values a nutritional balance among foods that fall across the dietary spectrum, this article is invaluable in learning to become a healthy vegetarian.
For a more Western perspective, read this article from the Mayo Clinic, or this excellent list of vegetarian nutrition resources from the Vegetarian Resource Group.