I have an idea. Maybe man is driven to our overeating for other reasons than hunger. We are brought up to clean up our plates before we can have dessert or leave the table. We tend to have an oral fixation. We have a wide variety of social occasions where food is served, and it is expected that one will partake as a matter of social courtesy, if nothing else.
Man often has mood swings and when depressed is inclined to resort to eating.
All this, not to mention that we are scheduled to three meals a day even if we are not hungry. We don't seem to question it. Even after going on a weight reduction diet, the rebound often only takes us to an even greater weight gain. Somehow, the body responds to starvation with the ability to use what food it gets more efficiently. With that increased efficiency, the slightest lapse in a starving diet will lead to more efficient use of food and more weight gain rather than loss.