Hi,
I completely avoid caffeine, alcohol, anything spicy, carbonated beverages and sugar alcohols when flaring and up until 2 months of steady remission.
I slowly bring in alcohol and watch it's effect on me. I've been fine drinking alchol since january 2009. I don't drink too often, but when I do they are binges... once every 2-3 weeks, but i have still been fine. I also have brought carbonated beverages back in, but i drink like 2 glasses/week.
I avoid the other stuff because I can live without it.
My last time i was flaring i had a fear of the things listed above. And it took me 4 months after i was in remission to try them again, just in case you feel that way, i don't know if it's normal, but it happens to me at least.
I've also started to eat spinach whenever possible! (As per sunflower and spinach posts) I don't know if that has anything to do with my continued remisssion for the past 8 months, but it could be helping me.