someone wrote:
Not gaining weight is primarily the function of biological imperatives as is the tendency of all animals given that being an animal is about economy of movement. Don't believe in biological imperatives? .
Yes, animals have a "biological imperative" to eat, store energy, and not do much more activity than is necessary to survive ( animals do enjoy moving around, to some degree, but when not given easy access to such "recreation" opportunities, they will more or less just sit there, and become depressed) In a cheap, easy-to-get, calorie laden environment, where not moving around much is easy, acceptable, the norm, and often fun (movies, video games, etc), and the environment is not one ripe with recreation opportunities, then too many calories consumed, and too few calories expended is the result, and an obesity epidemic is not surprising in the least.
Or we could just blame the Food Pyramid and carbs.