Much like caffeine, sugar is often consumed because it gives the body an immediate source of energy. As effective as caffeine for providing a short burst of energy, sugar’s high is also short-lived. Once consumed, sugar creates uneven blood sugar levels that can disrupt your sleep in the middle of the night as your body metabolizes the sugar and demands more.
Sugar induces hypoglycemia during the night, according to Kenneth Rifkin, N.D., of Lake Oswego, Oregon. Hypoglycemia, or low blood sugar (glucose), is a condition often associated with diabetes. Symptoms of hypoglycemia include anxiety, weakness, sweating, rapid heart rate, dizziness, headache, irritability, and poor or double vision, among others. Glucose is the primary source of fuel for the brain (although too much glucose in the blood can create health problems). Following a meal, glucose levels rise sharply, and the pancreas responds by releasing insulin, a substance that helps the cells absorb glucose from the blood. In healthy people, the release of insulin acts to keep blood sugar levels fairly constant; when the pancreas produces too much insulin, however, blood glucose levels drop suddenly, depriving the brain of needed fuel.
A diet high in simple sugars and refined carbohydrates can lead to nighttime hypoglycemia. Blood levels of glucose drop and the body releases adrenaline, cortisol, and other hormones to stimulate the brain and indicate that it is time to eat. This can awaken you or prevent you from entering a deep sleep state.
