Of drinking too much soda. I've narrowed it down to about a six pack of soda every two days... I know I know... too much. Drinking a LOT of water, about two gallons a day...much more than I ever drank before, but it's the soda that's keeping my stomach round..
Other wise my diet is pretty clean: tuna in water, chicken breasts, a cup or two of white rice, beans...and some vegetables mixed in.
Not really counting calories, because the only thing I consider sweet is the soda..