Need to lose weight? Try sleeping more. Unless you’re the type of person who raids the refrigerator while sleepwalking, missing out on a good night’s rest could make you binge on food—a lot. New research shows that sleep deprivation leads to a jump in eating. People who slept two-thirds of their normal amount—5.2 hours, on average—ate an extra 549 calories a day—about the size of a McDonald's Big Mac. If you did this every day, you could gain a pound a week. Even with more time in their day to move around, the sleep-deprived people showed the same activity level as the well-rested group. People allowed to sleep as much as they wanted—6.5 hours, on average—actually ate 143 fewer calories than normal each day. While these results are preliminary, "if you are looking to maintain a healthy weight or lose weight, I think getting adequate sleep may be very important," researcher Andrew Calvin, MD, MPH, told WebMD. What exactly is adequate sleep? The National Sleep Foundation suggests seven to nine hours a night for most adults, although there is no “magic” number. If you have a bad night’s sleep, consider locking the refrigerator to keep from overeating—both while awake and sleepwalking.