I'm not an expert but I'm gonna say sugar.
I am going to say it is a toss up between sugar and red meat. Neither of which is really bad, but both of which the American diet WAY overindulges in. In moderation no food is really bad.
what about the artificial sweetners in diet foods? ever read-up on what damage they do? Aspartame?
Twinkies. Cus they can survive nuclear holocaust.