The whole point of them is it really doesn't take that much food to fill people up... I can go to most restaurants and eat a feast for less than what it costs at most buffet places.
Honest, we try to stuff ourselves blind, but we are probably better off cooking at home and or eating moderate portions for less... The biggest loser in this game is your health, (and your class, too ), if you really try your best to hammer a buffet place. There really are better things to do.