There are three basic types of diets used in diabetic dogs; low carbohydrate, low-glycemic index and high insoluble fiber. In the first two diets, fat and protein are used to replace the calories normally obtained from carbohydrates. Unfortunately, high fat content may cause pancreatitis, especially in animals that have already suffered from an episode. The high protein diets are contraindicated in patients with liver and/or kidney problems. Therefore, I prefer high insoluble fiber diets for diabetic dogs. Please remember, this is my diet recommendation for dogs, not cats. In my experience, diabetic cats do better on high protein/low carbohydrate diets.
How does the insoluble fiber work? Insoluble fiber cannot be digested by animals (including people) who have a single stomach digestive system. Digestion requires multiple stomach compartments and mechanical degradation i.e., chewing cud, to break down these ingredients into useable material. When the insoluble fiber passes through the gastrointestinal system of a monogastric animal, it slows the absorption of carbohydrates. This is how the blood glucose levels are reduced. Hill’s RD and WD, Purina DCO and Royal Canin Calorie Control CC High Fiber are a few examples of high insoluble fiber diets.
But the most important factor in diet for diabetic dogs is consistency. In my opinion, the best regulation occurs when owners feed their dog the same amount of the same food at the same time twice a day. This works because I can match the amount and type of insulin to the glucose load the dog ingests. Regulation problems occur for two reasons: The dog is not on a schedule and those notorious treats. Treats are often loaded with carbohydrates that make regulation a nightmare. I recommend no treats if possible. If you must give your pet a treat, I recommend using a few kibbles of their own food. If that is not acceptable, then vegetables low in sugar are the next best thing. Avoid biscuits, crackers and other carbohydrate rich foodstuffs.
Chastain, C.B., et al. “Effects of Insoluble and Soluble Dietary Fiber on glycemic Control in Dogs with Naturally Occurring Insulin-Dependent Diabetes Mellitus”, Sm Anim. Clin. Endocrin. 200 Sep-Dec;10 (3):15.
Nelson, R.W., et al. “Effects of Dietary Insoluble Fiber on Control of Glycemia in Dogs with Naturally Occurring Diabetes Mellitus”, JVMA, Feb 1998; 212(3): 380-6.