Buffet

We went to the buffet with my grandma on Saturday. Why is it that fat people and old people love the buffet? I understand that you can eat as much as you want but these two groups of people can barely walk yet they love to go to a buffet where they have to walk around to get their food. For what it costs to go to a buffet you could go to a chain restaurant and get a good meal but still these people love the buffet. It makes no sense to me why these places are so popular.