I’d suggest clearly distinguishing between soluble fiber and insoluble fiber. Lots of J-pouchers (but not all!) report having to be careful with insoluble fiber (salads, fruit skins, etc.), but soluble fiber (e.g. psyllium) behaves very differently in the gut, and helps many of us. Most of the widely available dietary advice about fiber is about its behavior in the colon, which just doesn’t apply to us.