Research has shown that sleep deprivation can have a significant impact on your ability to lose weight. The major players in this snooze-lose link are two hormones: leptin and ghrelin. Lack of z's results in lower levels of the appetite-suppressing leptin and higher levels of the appetite-boosting ghrelin. Compounding this hormonal glitch is the simple fact that when we sleep less, we have more opportunities to eat. Also, when we're tired from lack of sleep, we have less resolve to fight cravings and mindless munching. The obvious solution to this problem is to get more sleep — aim for at least seven hours a night. And before you say "impossible," think about this: One study showed that the difference in the amount of shut-eye between obese subjects and slim ones was about two hours a week — that's only 17 minutes more sleep per night!