He may have a food intolerance to the kibble. Has he been to the vet for a check-up?
I would recommend eliminating all dry food from his diet, which tends to have too many carbs and fillers that can trigger digestive issues. Might also be worth trying some different canned foods, or even a raw diet if you're up for it. Here is some great info on feline nutritional requirements: www.catinfo.org