The Truth Behind What Intermittent Fasting Does to Your Body

By Alexandra Pattillo Ever feel hangry when you miss a meal? Imagine waiting 16 or 18 hours before eating again. Or an entire day without breakfast, lunch, or dinner. That’s what proponents of intermittent fasting do on a regular basis. At its simplest, intermittent fasting (IF) means cycling through periods of voluntary abstinence of food (or significant calorie reduction), interspersed with intervals of normal food intake. Whenever we eat, the body releases insulin to help cells convert sugars (in particular glucose) from food into energy. If the glucose isn’t used immediately, insulin helps makes sure the excess is stored in fat cells. But when we go without food for extended periods, as people do in IF, insulin is not released. The body then turns to breaking down fat cells for energy, leading to weight loss. “That’s why we have fat stores and if we’re not using them, all kinds of bad things happen.” Monique Tello MD, MPH, a Harvard Medical school professor and internal medicine physician at Massachusetts General Hospital, explains to Inverse what happens when people never get hungry enough to use up those fat stores. “A, we get fatter and B, it’s all the things that go along with that,” she says. “Your blood sugars are constantly high. Your insulin levels are constantly high. You get type two diabetes, which is a huge epidemic. Those high blood sugars cause damage to the insides of our a