Sugars are added to dog foods because dogs, like humans, like them. They can come be listed in a number of ways (sugar, caramel, syrup, sucrose etc.) and can come from a wide range of sources (corn/maize, wheat, sugar cane, sugar beet etc.). Unfortunately, too much sugar can have the same effects in dogs as it does in people. High sugar diets have been linked to hyperactivity, hypoglycemia, obesity and tooth decay amongst other conditions and should therefore be avoided.