fat boxers??!!

always amazed me how at least half of pro HWs are overweight, some slightly, some VERY. i mean i know there's no weight limit but how on earth can they expect to compete when overweight? i'm not a pro athlete, i probably drink too much, at a weekend at least, and only eat reasonably well (odd burger king now and then but mostly eat sensibly) and go the gym or for a run 3 or 4 times a week and i'm not fat so how and why do men who rely on fitness and stamina allow themselves to get so fat? if i was a even a semi-decent pro i'd have a better body than most of them. this thread isn't really a question i'm just wondering why some fighters are fatter than some people who don't even try and keep in shape. surely training consistently for fights must keep you at least semi- slim??!!