My GI's office actually has a nutritionist that comes in every other week. I saw her after the pred left me lugging around extra weight that I couldn't lose. (It's hard to diet when you can barely tolerate any fruits or vegies.) She devised a UC friendly diet that worked with my particular routine. stuck to the diet for about 3 months (this is 2 years ago now) and felt much better physically - but because my body did not tolerate the pred well - I barely lost any weight. So I stopped. However - this past winter I noticed that the weight was finally starting to drop so I went back on the diet she gave me and lost all that pred weight within 2 1/2 months. I feel great and now I just stick to her plan on a daily basis with a few snack cheats here and there and am maintaining my weight perfectly and my UC is behaving itself.
I definitely think it's worth a consultation. I only saw my nutritionist twice - but it was well worth it.