There are several of us here who have diabetic kitties with IBD. Mine is (or was) diabetic but his BG has gone down to normal levels after a couple weeks on insulin and no dry food. I tried many novel protein cat foods and the one my cat seems to like the most is duck. Natures Variety makes a high protein canned grain free duck with low carbs. They also have other novel protein sources. Not sure of the exact carb count though. Hills dd grain free canned makes a novel protein limited ingredient food but I don't think the carbs are really low. Budesonide is sometimes used in IBD cats who have diabetes in lieu of prednisone as the side effects and effects on glucose is supposedly milder. I am facing this now as my IBD cat is having some problems and I think my only choice will end up being the budesonide which may return him to a diabetic state. It's really difficult when they have both. The good news is there is more of a variety of novel protein limited ingredient foods now then there used to be.