I used to be able to eat anything I wanted.
7 full plates at a buffet were the minimum, and a full 18 inch pizza was easy even though I weighed 160 lbs at the time and have never reached 190 in my life.
Those days are over. Now that the metabolism is slowing I have to eat like a mere mortal...but I still show slivers of greatness at a buffet table, last year I lost count of oysters and clams at a raw bar buffet at 50 and that was on top of a full lobster (this was, however, over a slightly more extended period.)
EDIT: I should also mention that after the above shellfish incident I discovered I have a mild version of my mother's shellfish allergy. Not fun.