I was able to go back fairly quickly, but it's good to take precaution.
I started off by re-introducing things like red meats and cooked veggies in small portions in one meal a day. Still stayed completely away from raw fruits/veggies and skins, dairy, and spicy. After a few days, I increased the amount of regular foods and continued to do so each day. After a week, I was back to a basically normal diet (still a little precautious with minor things).
That's when I did the same process with spicy and dairy (slowly increased amount). If I had a problem, I backed it down again. Took about another week to get those re-introduced. Now I'm pretty much eating whatever I want in whatever quantity.
I've been symptom free for about 3 weeks but I'm still avoiding the very abrasive stuff (corn, skins, etc). I want to be 100% healed before I touch that. I think those are the biggest enemies, but of course we all have our specific problem foods.
Good luck and glad to see you're feeling better!
juju / UC Since July 2001
Flares: Jan 2006, Feb 2010
Currently: 99% Symptom free ;D
Asacol HD 800mg x4/day, Canasa suppositories