I think the rise in popularity of Vegetarianism in Western culture has been the result of the wide availability of alternative eating styles that remain healthy. For many it is easy to pop inside a grocery store and buy protein and other vitamins and minerals that are harder to find in a purely vegetarian diet. In many other cultures, this is the not the case. People simply don't have the choice to refuse all meat products because of the health ramifications or simply a scarcity of money and food . However I don't think it is a "purely" western idea. Vegetarianism exists in many cultures and religions, though perhaps less abundantly.