From virtually everything I've had read, there is actually very little if any objective clinically proven correlation between food and the development of pouchitis - meaning, basically, that food does not in and of itself cause pouchitis. However, certain foods -- some of the most common including excess sugar, dairy, starches, and spicy foods -- may aggravate an existing case of pouchitis in some people. In that case, individuals who find they are sensitive to those foods or that such foods make their pouchitis worse, might more effectively manage their pouchitis symptoms if they reduced or eliminated the intake of those foods. That being said, there is certainly no guarantee that eliminating any potential trigger foods will amount to a reduction in pouchitis symptoms. The other complicated thing is that "problem foods" will vary widely from person to person, so just because one individual seems to do better by eliminating a food category such as white bread or pasta, for instance, does not mean another person will have the same results by following the same plan. On the flipside, while some people might do better with dietary modifications to manage their symptoms, there is no proof that any specific diet entirely "cures" pouchitis. There are numerous people with chronic pouchitis who follow various diets (vegan/vegetarian, FODMAP, lactose free, glucose free, etc) but still report little change in their pouchitis symptoms. So again, diet and pouchitis are one of those vary individual and controversial issues for which there isn't one universal answer.
What it comes down to, as with everyone, is that we are all individual, and that our results can really only be determined by trial and error. If you have discovered that some foods aggravate your pouch and that your symptoms are mitigated without them, then definitely you should systematically reduce or eliminate them from your diet. But unfortunately this does not mean that another person will have the same results by following the same plan, nor that there is one specific plan all those with pouchitis should adhere to.
If only it were that easy.