I think that a colectomy is unlikely to fix your food sensitivities. I guess you could get lucky, but I sure wouldn't count on it. Is that what you were asking?

Yes, I agree with Scott, in that surgery is not necessarily an automatic fix for food intolerances. That being said, unless you have bonafide food allergies or problems with lactose or gluten, for instance, it may be that certain foods that aggravated your UC may not in fact be as problematic once you colon has been removed, since you won't be in active flare. In general, many people find they are able to better tolerate a wider variety of foods after removal of their colon as compared to when they had active UC.  The problem is, we are all highly individual, so it's impossible to predict what your own outcome will be. You may be lucky and be able to eat almost anything, or you may have similar food restrictions as you had before surgery.  In most cases, it's a process of trial and error. After surgery, it's recommended that you introduce foods back into your diet slowly, a few at a time, and see how you react. Some people find it helpful to keep a food diary, so that they are more easily able to identify foods that cause problems. You may in fact find that once the UC is "cured" then some of the foods that gave you issues before will no longer cause problems.

Of course, just being potentially able to eat more foods is not in an of itself a reason to opt for this surgery; though it is potentially one of the bonuses of a successful j-pouch. I think it's more your overall health that you should be concerned about. If you have been in an active flare for 3 years and have never achieved remission, surgery is absolutely something you should consider.

I read the OP as asking about food allergies (e.g. peanuts, milk, etc.). Spooky's post made me realize that the question was more likely about the broader food intolerances common with an inflamed colon. I think most J-pouchers see substantial improvement in that area. For a long time (for example) I couldn't handle anything more complicated than ramen. After my  J-pouch surgery I began eating anything and everything, and could finally enjoy coffee. I apologize for (probably) misunderstanding the question.

Yes, that's the thing. You'd have to know whether it's a bonafide allergy or intolerance separate of UC, or just a result of being in active UC. Basically, even though my UC was acute and was only in full flare for about 6 weeks, I could eat virtually NOTHING.  I ended up on liquid diet and later on TPN. Obviously now I can eat a great deal more.