Victor had IBD, and we tried to get him to eat i/d which is generally considered the "bland" diet - but it's very high in carbs, and not agreeable to a diabetic. Besides, he wouldn't touch it. I switched him to raw, and almost overnight the diarrhea abated. He had a lot of other health issues to dance around, but the raw certainly helped with the loose stools.
Also my dog had severe IBD when we fostered/adopted her, among other problems (all of my animals have special needs...). When she gets a flare up, we mix i/d with her prescription dry food. She thinks it's a delicacy, but the cats wouldn't go near it.
ETA: we've also used a mixture of rice and boiled hamburger for a less expensive alternative to i/d. I cooked the rice, boiled and drained the burger and ran it all thru the food processor with some plain water for consistency. Again, not ideal for a diabetic, but if diabetes is not an issue, it might help.
