He is on a holistic/organic diet, for the most part. The treats I feed him are the healthiest I can find...I stay away from the scooby snacks, etc...(can't think of any of the names at the moment, lol). I can't imagine it being sugar. My family and I are semi-vegetarians and try as best we can to eat organic and natural foods.....so I'm trying to stick to the same with my little Lewis....although he's allowed beef and other meats, lol..... that would just be mean to a pup!