Hill's Prescription Diet W / d Canine w / d Digestive Weight Diabetes Management Main benefits Clinically proven nutrition that can transform your pet's life. Prescription Diet (TM) Canine w / d (TM) has the following key benefits. Once your dog has achieved the ideal weight, you can help him maintain it by administering the Prescription Diet products for weight management. Low in calories and fat, to maintain the ideal weight. High in dietary fiber to help reduce hunger and discourage continued food demand Integrated with L-carnitine, a vitamin that helps burn fat and maintain muscle during weight loss.