Testing with 3-4 day waterfasting is a good start.
Ulcertaive colitis is, briefly described, advanced inflamation of the lining of the small intestines?
If you've got bile trickling at a constant rate over the small intestine, it won't be getting a rest to heal up.
Fasting -may- help in the respect that there's less activity that will happen (less food running through the tube) for a period.
On the diet side, the alkaline diet is likely an important shift to make in your patterns, very lightly-steamed and raw veggies being the foods that will trigger less bile release for periods where you need to heal up.
The byproduct of digestion of fiberous veg helps with inflammatory bowel conditions because the bacteria use the fiber to make butyrate, which soothes the bowel wall.
AND the fruit and veg based eating (mostly raw) IS the reccommended lineup (activity) reccommended before you start a fast!
In the case of repairing the issues that caused the need for surgery (and the following painful bowel), I can highly reccommend prayer. Miracles should not be underrated, because Jesus offers them freely. ;)