Bad Fruits For Diabetics. Fruits with high amounts of the sugars glucose and sucrose tend to have high GI values and should only be eaten in small amounts as they can spike blood glucose levels very quickly.Most however can still be enjoyed in small quantities as part of a healthy diabetic meal plan.High GI fruits include bananas, cantaloupes, dates, grapes, watermelon, pineapples, and oranges.ost however can still be enjoyed in small quantities as part of a healthy diabetic meal plan. High GI fruits include bananas, cantaloupes, dates, grapes, watermelon, pineapples, and oranges.