There are no particular regulations on sugar consumption for diabetics, but someone with Type 2 diabetes should not have more than "30-60 grams of carbohydrate per meal," and "15-30 grams per snack," according to registered dietician Amy Campbell. Carbohydrates, and not sugar, cause blood glucose levels to rise and can be harmful to diabetics. Sugar is just one type of carbohydrate.
When someone has diabetes, the cells fail to respond properly to insulin, as indicated by Healthline. Insulin helps to break down carbohydrates in the body. This means that the body may not be able to effectively process blood sugar or glucose. Glucose levels tend to become abnormally high, which is why carbohydrate intake needs to be restricted. Carbohydrate intake should be limited to 45 to 65 percent of total calories per day.