Historical development of vegetarianism.

Vegetarianism pursued for reasons of physical health is a recent practice historically. Before the 19th century, avoidance of animal food was justified with moral and metaphysical arguments. During the early 1800s, however, an intensified desire for improved health combined with the ascendance of science to a position of cultural authority helped to promote the formulation of physiological arguments for vegetarianism. Theories of the nutritional superiority of a vegetable diet were nevertheless shaped by moral convictions, giving vegetarian spokesmen such as Sylvester Graham and John Harvey Kellogg the appearance of being dietary fanatics. Only as nutritional science expanded from the mid-20th century onward did vegetarianism acquire general recognition as a healthful dietary alternative. But because that alternative is still often selected for moral or other nonscientific reasons, nutritional education of vegetarians remains an essential activity.