Originally Posted by Ratzinger

Actually, as OP later elaborated, his question was really about how people can let themselves be fat, not really about how a potbelly is formed. He just can't understand how some people would let themselves appear to be unathletic.

His question was not about physiology but a perceived character flaw with which he cannot empathize nor understand, and it's not unreasonable to doubt his sincere desire to reach any kind of understanding in the first place.