In the cat there are factors that help them to respond well to therapy. It is important to feed wet cat food and no dry food at all if possible and all foods including treats should consist of ingredients suitable for a diabetic. You can try canned DM by Purina (Prescription food) or if he doesn't like it, a canned food that is less than 2% carbohydrate such as Friskies Classic Pate Salmon, Fancy Feast - Savory Salmon Feast, Turkey and Giblets Feast, and White Meat Chicken Florentine. In addition I give digestive enzymes, probiotics and fish oil. Dia-IonX helps the body to better utilize the diet and supplements better for a synergistic effect for faster healing. It is also important to avoid giving water that contains chlorine and fluoride.
Exercise helps to move glucose from the blood into the muscles which will lower the blood glucose. Hopefully you can get your cat to play.
Please let us know how you do or if you have any other questions.