The sugar in fruit is not bad when it comes to diabetes, according to Mayo Clinic. Fruit is considered a carbohydrate in a diabetic's meal plan, and the number of carbohydrates a diabetic eats is determined by his glycemic index.
The glycemic index, as explained by Everyday Health, is a rating that is assigned to carbohydrate foods that shows how rapidly a particular food affects blood sugar levels.
Fruit typically contains 15 grams of carbohydrates, according to Mayo Clinic, and can be exchanged for other sources of carbohydrates in a meal plan, as explained by the American Diabetes Association. Most fruits have a low glycemic index.