Rosenfeld’s experience is hardly mysterious: Sleep deprivation has been scientifically proven to contribute to an unhealthy boost in appetite the next day. “Laboratory studies have shown that sleep loss stimulates appetite and increases cravings for high-calorie foods, therefore increasing the risk for weight gain,” said Dr. Esra Tasali, an associate professor of medicine and the director of the Sleep Disorders Center at the University of Chicago. “We have known this for a while.” But now, thanks to a new study spearheaded by Tasali, we know that the reverse is also true: Getting enough quality sleep causes us to eat less than when we’re sleep deprived, thus increasing the likelihood of healthy weight loss.