Posted 1/12/2014 8:40 AM (GMT -6)
I'd give a new diet about a month, then try reintroducing the food(s) you excluded. Once you reintroduce things, keep a log and see if your symptoms change. There are a variety of diets to try, gluten-free, lactose-free, resistant starch, scd, paleo, etc. Some of the diets excude many of the suspected problem foods for uc in one go. Diet mods don't work for everyone, but some have had improvements in uc symptoms.
If you are allergic to something, exclude it, then the change would be very quick. If you have a name non-celiac-gluten-intollerence, you'd notice an improvement by excluding gluten but it would be a slower improvement over a week or weeks.