For me, foods that caused problems with my bag were different than things that caused problems with my pouch and the nutritionist that I worked with had little/no experience with pouches. So, it was kinda trial and error for me.
Starchy foods should thicken your stool, like potatoes. I never had any blockages from them. Just be careful what you eat them with. I love green beans and eat them all the time with no problems at all.
Insoluable fibers are not my friends... celery, apples, orange membranes, etc. I can eat apples if I grate them, celery if it’s cooked, oranges if I take the membrane off the fruit. Mushrooms are pretty much out of the question for me. Also, watch out for lobster and prawns. I love them but never make them for myself or order them when I go out, luckily my hubby will share a bite with me and I get my “fix”.
If you are not sure how you will respond to a food that you haven’t eaten with your pouch try a small amount and pay attention to what you are pairing it with.
Good luck.