Low blood sugar at night (called nocturnal hypoglycemia), can often happen without symptoms and can last for a long time. Doctors often suggest that patients take a bedtime snack to try to prevent low blood sugar at night from happening, but it is not known what type of snack is best to take. We are conducting a study to evaluate how two different types of snacks affect how often the blood sugar is too low overnight. One snack will be a primarily carbohydrate snack and the other will be a carbohydrate snack with fat. The snacks will be provided by the study.