New research shows that sleep significantly influences metabolism, appetite and weight management. Could getting more shuteye help you ward off excess pounds? When I was in college, I often began my homework at midnight. Nothing seemed to focus my thoughts on a term paper better than a morning deadline. I knew this routine wasn’t a wise one — after all, I might crash facedown in my textbook. But I told myself that adrenaline improved my writing. Besides, I figured I was losing weight on those nights with only four hours of sleep. I assumed that all that effort to stay awake and functional had to be zapping away the day’s calories. Turns out that I was greatly mistaken.