I worked at a Ponderosa for three years in college, and trust me when I say that the overweight to healthy weight ratio was no different inside the restaurant than anywhere else I've seen in America - including at the gym! There are some very uninformed posts in this thread about buffet restaurants and overweight people. As a matter of fact, my customers who ate the most were athletic younger guys. Generally people who really piled food on their plates left most of it when they were done. I cannot tell you how much food gets thrown away at a buffet!
The only buffet restaurants I personally eat at are Sweet Tomatoes and a local Indian restaurant. But I'm not so much of a snob that I would say (or imply) that all people who frequent buffet restaurants like Ponderosa and Golden Corral are fat country folk.
That's incredibly far from the truth as I've witnessed it.