Again, this is a personal thing. Some people need to be very selective with an IC diet while others are not affected. This is a trial and error that you must go through to see if it is right for you. The most frustrating thing about the diet is that unlike diabetes, there can be no immediate consequence for eating a taboo food. If I have a glass of orange juice, I may be ok. But, if I have a slice of tomato in my salad for dinner (totally forgetting that I had the oj) then it is pain city!
I have a sensitivity to acids like citrus juices, raw tomatoes/peppers/onion/cucumbers. A lot of chocolate, carbonated drinks, and coffee will hurt too.