Roberta, there's nothing wrong with feeding beef, chicken, or tuna as long as Tuffy's daily caloric intake remains the same. If you increase his caloric intake, you'll need to increase his insulin dose and vice-versa. If you prefer to cook for Tuffy, here's a balanced home-cooked recipe for a diabetic:
chicken breast, without skin, cooked, 6 ounces
barley, pearled, cooked, 3 cups
beans, red kidney, canned, drained, 1 cup
broccoli, chopped, cooked, 1 cup
canola oil, 2 tbsp
salt substitute (potassium chloride), 1/2 tsp
bone meal powder, 2 1/2 tsp
salt, iodized (sodium chloride), 1 3/4 tsp
multivitamin & mineral tablet, kids complete, 1 each
zinc, 100 mg tablet, 1/2 tablet
Provides a total kilocalories as prepared of 1468 kcal, the daily requirement of 68 lb dog. Uneaten food can be refirgerated for 3 days or frozen indefinitely while watching for spoilage.
Please respond with further questions or concerns if you wish.