The highest quality dog food would be one you made yourself using lean pasture raised meats and wild caught fish, fresh organic vegetables and a few supplements.
In commercial dog foods I would rate them as follows:
One of the issues with a very low carbohydrate food for dogs is the fat content. Most commercial foods with low carbs are high in fat, some are really high. If your dog doesn’t have any other health issues he or she might do fine with a high fat, high protein, low carb diet. If your dog has other issues such as pacreatitis a high fat diet might not work as well.
I strongly believe that with a diabetic dog the number one priority is to limit carbs as much as you can. After all, diabetes is a failure of the bodies ability to regulate and metabolize ALL carbohydrates and injected insulin cannot currently duplicate the bodies own production of insulin. Diabetes CAN be controlled with the proper diet, the proper insulin regimen and home testing of blood glucose.
So please tell me a little bit about your dog:
Current food and amounts fed and at what times in relation to insulin injections
Current insulin regimen, what type, how often
Current blood sugar readings
Overall health and any issues besides diabetes
Once you develop a routine that works for you and your pup things get easier! Give your pup a hug for me!!!