Caffeine, especially with the Fibro. I now think of it more as a medicine with nasty side effects. So if I REALLY need the caffeine, I'll have some and put up with the side effects, but I don't have it for fun anymore. That make sense?
Anyway, not counting the caffeine, coffee is a big one for me as I adore it.
Salad used to be, but it was so painful I don't push it anymore. I can eat loads more fruit and veg now than I used to be able to, so that's not an issue anymore.
Fatty stuff is a big issue for me as I'm ALOT more fat tolerant than most people...well, it makes me C but as my attacks are D, sometimes that's good. So chip shop fries etc...yum!