Cheat yourself of two or more hours of sleep each night this workweek and you may find yourself two pounds heavier by Saturday—as volunteers did in a study at the University of Colorado at Boulder. Eating more is one explanation
. The other is what
you'll eat: pasta, cake, bread—anything high in carbs—especially after dinner. Even a night or two of short sleep boosts the hormone ghrelin
, which stimulates the appetite, and decreases leptin, which suppresses it.