Sugar is not a normal part of a dog's diet. It can lead to tooth decay, diabetes, obesity and spoil their appetite. We wouldn't recommend feeding a dog sugary foods on a regular basis. We might recommend a drop of karo syrup for a dog that was not eating to keep their blood glucose levels up but would never recommend a diet with sugary foods as a part of it.
If your dog was diabetic, it could even send them into a coma and kill them. Artificial sweeteners can also be a problem with some of them Toxic to dogs. I hope this answers your question.