If you’re struggling to sleep, it could be time to change your diet. Researchers at Columbia University Vagelos College of Physicians and Surgeons reported in the American Journal of Clinical Nutrition that there’s a link between high-glycemic foods and the risk of developing insomnia.
The glycemic index (GI) assigns values to foods based on how rapidly they increase blood sugar. Foods are categorized as low (≤55), intermediate (56–69), or high (≥70) on a 100-point scale. When we eat low- or intermediate-glycemic foods, blood sugar rises gradually and the body releases insulin to balance the glucose. High-glycemic foods, however, set off a roller-coaster reaction. Blood sugar soars to a high level in what’s called postprandial (after a meal) hyperglycemia (high blood sugar). To compensate, the body releases a large burst of insulin that can lower blood sugar too much too quickly. If blood sugar drops below about 70 milligrams per deciliter, the brain doesn’t have enough glucose, its primary fuel, so the body releases adrenaline and the stress hormone cortisol. Release of those counterregulatory hormones can cause heart palpitations, tremors, cold sweats, anxiety, irritability, and hunger. If that’s not enough to disrupt sleep, high-GI diets can also cause an inflammatory immune response that inhibits sleep, as well as intestinal dysbiosis.
While high-GI foods appeared to increase insomnia risk in this study, foods such as whole grains, vegetables, and whole fruits—but not juices—lowered it. Although fruit is full of natural sugar, its fiber helps prevent blood sugar spikes.
While this study focused on postmenopausal women, the authors speculated that the findings are likely universal. For anyone struggling with insomnia, replacing high-GI foods with minimally processed, whole ones—including carbohydrates like whole grains and sweet fruit—could provide some relief.