What food should I feed my diabetic dog?

Diet is indeed extremely impportant for the diabetic, and any change you make will likely effect her insulin requirements. I agree that w/d is not the highest quality commercial food you could be feeding, but because of the necessity of keeping the diet consistent, I would not try to switch to home-cooking. I would gradually try switching to a higher quality dry food such as that made by Wysong, and eventually add in fresh vegetables for additional nutrients. I also use a dietary suplement for Diabetics called Glucuril from Phytopharmica which contains chromium, bitter melon extract and other ingredients important for glucose metabolism.