90% of Victims with Interstitial Cystitis will report food triggers. A recent article did a survey and summarized which are good and bad.
BJU Int. 2012 Jun;109(11):1584-91.
Diet and its role in interstitial cystitis/bladder pain syndrome (IC/BPS) and comorbid conditions.
Friedlander JI, Shorter B, Moldwin RM. abstract here
I hope that gives more ideas on diet.