"Sleep on your left side," says Anthony A. Star-poli, M.D., a New York City gastroenterologist and assistant professor of medicine at New York Medical College. Studies have shown that patients who sleep on their left sides are less likely to suffer from acid reflux. The esophagus and stomach connect at an angle. When you sleep on your right, the stomach is higher than the esophagus, allowing food and stomach acid to slide up your throat. When you're on your left, the stomach is lower than the esophagus, so gravity's in your favor.