A liquid diet (parenteral nutrition) may be as effective as steroids at inducing remission. You can talk to your GI about
going on a prescript
ion meal replacement. It allegedly tastes horrible and some people opt to do it via NG tube, but it could help you.
EDITED to add that the use of parenteral nutrition shows a significant improvement for people with Crohn's colitis, not so much for Ulcerative Colitis.