We do not add sugar to our Wagg dog food but there are natural sugars present in the ingredients. Usually complex carbohydrates, such as those found in whole grain, are best as these are broken down in the digestive system slowly and so avoid peaks and troughs in the sugar levels in the body. In most of our foods we do use whole grain wheat and/or maize which take longer to digest. We therefore do not recommend grain free food for diabetic dogs. It is often a good idea to feed your dog small portions of food more often as this will also help to keep sugar levels stable.