The practice of vegetarianism, however, goes far back in history. Many noted philosophers and religious teachers urged their followers to avoid flesh diet. There are various types of vegetarians. Vagans are the strictest Vegetarians who eat only plant foods and exclude all animal by-products such as eggs, milk, cheese, curd, butter, ghee and even honey. There are lacto vegetarians who eat plant foods as well as dairy products and lacto-ovo vegetarians who eat eggs besides plant foods and dairy products.
Meat seems to have assumed an exaggerated importance nutritionally.
It is generally mistakenly believed that nutritional deficiencies, especially of proteins and vitamin B12 and poor health may result if animal foods are eliminated. Studies, however, have indicated no health problems or deficiency diseases for those on a vegetarian diet. The so-called protein deficiency in a vegetarian diet is in fact more imaginary than real as the contribution of the protein value of green vegetables has been ignored and the true protein requirement is less than that assumed. Green vegetable protein is as high in quality as milk protein and thus makes a very valuable contribution to the vegetarian's protein nutrition. The high quality of this protein balances the lower quality of other vegetarian proteins such as nuts and beans.