I know the thing that triggered my two major flares was drinking coffee for several days in a row. It seems like doing it once won't bring a full on flare, but too much too many days in a row is a no-no.
I also have noticed that when I'm not in a flare, I can eat just about anything. But when I'm sick, I can barely eat anything except for oatmeal, mac n cheese and jello.
Other culprits for me are: fried food, soda, and sugar. Corn doesn't help the belly much either.
I just finished an elimination diet of wheat and dairy and I have to say I was worse without the wheat, I don't think whatever I was replacing it with sat with me real well. Maybe too much soy products?
Good Luck in finding all your triggers!