Hi Ox,   I'm sorry to say there isn't just one answer to your question. For some people food isn't an issue with their Colitis, even during a flare-up - my father falls into this category. For others, like me, I need to eat what I call a "white and light diet" during a flare up. What I mean by this are foods that are easy on the gut and easy to digest. Think baked chicken breast, baked white fish, white rice, white toast, applesauce, yogurt, bananas. These are foods that provide nutrients and sustenance but are pretty easy for your gut to handle and digest. Foods to avoid while during a flare tend to be things like spicy food, whole grain/whole wheat, brown rice, red meat, soda, caffeine, citrus fruits, raw or undercooked veggies, etc.   It will take some experimentation on your part. Maybe start keeping a food journal where you write down what you eat and how it makes you feel. I did this for nearly a year and it helped. You also might want to read my new Sharepost about the Elimination diet. It really can help.   Best of luck, Elizabeth