The untold story of the recent Olympics

Iss really not as dramatic as the title suggests, but I can't quit wondering that if Michael Phelps' diet consists of 12,000 calories per day, how much does that increase his risk of stomach and digestive-tract -related diseases? It is entirely likely that his diet will be elevated only for a short number of years (maybe significantly elevated from 16 to 32 but only this peak level for 8 to 10 years?) but during that time he will have eaten significantly more food than the average person of his size. It is entirely possible (since 12,000 is probably 3-4 time as much as the average American eats in a day) that by age 30 he has eaten as much food as most 50- and many 60-year old men. That can't be good, can it?