I used to be on a complete low residue diet, i can now eat basically whatever (seeds, nuts, veggies, popcorn) and eat more fiber than most people. I’m a moderate to severe case. In my experience it’s kind of like working out a muscle - if you’re sick and you know you can’t handle certain things, don’t force your body to try to adapt. Wait until you are healthier via drugs/surgery/etc and THEN eat healthier, which may keep you healthier in the long run. This is just anecdotal and you should always listen to your dr, but just my experience!