Non-diabetic hypoglycemia is a condition that causes the sugar (glucose) in your blood to drop too low. This can happen in people who do not have diabetes. The 2 types of non-diabetic hypoglycemia are fasting hypoglycemia and reactive hypoglycemia. Fasting hypoglycemia often happens after the person goes without food for 8 hours or longer. Reactive hypoglycemia usually happens about 2 to 4 hours after a meal. When your blood sugar level is low, your muscles and brain cells do not have enough energy to work well.