While there is no evidence that diet causes UC, diet does play a very strong role for many who have the disease. Avoid any foods that cause
diarrhea. Eat lots of spinach
and other dark green leafy vegetables (assuming they do not give you diarrhea). Avoid foods, beverages, and ingredients that are hard on the liver, such as alcohol and high fructose corn syrup (HFCS). Poor digestion can trigger flares.
And try to reduce stress as much as possible. Get plenty of sleep, meditate, etc..