I receive this question almost on a daily basis. Veterinarians often recommend a prescription food when a dog is diagnosed with diabetes. Unfortunately, prescription diets are quite costly, especially when you consider that diabetes is a lifetime disease in dogs. Most veterinarians understand this situation and will consider other diet options. Provide your vet with the information from the package so that they can help determine whether or not the diet is a good choice.
For diabetic dogs, low fat and high fiber diets are the very best at managing blood sugar levels. Many pet parents would like to feed a grain free food to their diabetic dog. Unfortunately, many of the grain free foods in the marketplace are high in fat. Dogs with diabetes are more susceptible to suffering from pancreatitis. This is a painful and potentially life-threatening medical condition. Although some dogs will still develop pancreatitis even when eating a low fat food, they are much less likely to do so than if they were eating a high fat formula.
Feed a weight management formula and look for fat levels in the Guaranteed Analysis of less than 10%. Fiber is usually between 2-4% in a low fiber ration so look for fiber levels higher than this. Some popular over-the-counter pet foods have fiber levels as high as 8-10%.
If your pet is being managed on insulin and is well controlled, a diet change can change the insulin requirements. Transition slowly and make sure to work closely with your veterinarian to adjust insulin levels.