Q: I'm having trouble controlling my weight. Aside from a healthful diet and exercise, is there anything else I can do?
A: Yes. Go to sleep. Surprisingly, people who miss out on sleep tend to gain weight. In the 1980s, U.S. government researchers tracked sleep patterns among Americans as part of the National Health and Nutrition Examination Survey. Those who slept only five hours a night were 60 percent more likely to be obese than people sleeping a normal seven to nine hours. And those who got only two to four hours of shut-eye were more than twice as likely to be obese.
A University of Wisconsin study of more than 1,000 people found the same thing: you're more likely to pack on the pounds if you skimp on sleep.
Why does this happen? The first reason is obvious: you can't reach for a doughnut if you're unconscious. Turning out the lights puts a stop to late-night snacking.
But there is more to it than that. Physically, sleep helps you in three ways: First, sleep restores your appetite control. Let me draw an analogy: if you've been on the highway at night, you've probably noticed that road crews do most of their work during this time, before the morning rush hour begins. Your brain takes advantage of downtime too. When your daily activities are over and you lapse into sleep, your brain gets to work. It restores your appetite monitor, among myriad other tasks that it performs to get you ready for the day ahead. Blood tests prove it. When you're asleep, your body produces more leptin, an appetite-managing hormone. If you stay awake on into the night, your normal leptin surge is reduced, which means less appetite control the next day.
Second, sleep restores your emotional equilibrium. If you find yourself eating because of stress, anger, or loneliness, it's important to remember that emotional problems (and physical ones too) disturb you more when you're sleep-deprived. When I was in medical school and residency, I could always tell who had been on call in the hospital the previous night. Sleeplessness made them moody—sometimes grouchy, sometimes giddy, and generally unpredictable. A good night's sleep helps to mend your mood, and that helps you avoid stress eating.
Third, sleep restores your energy. If you're physically worn out, it's more tempting to sideline any plans you may have had to work out at the gym, go on a long walk, or take care of yourself in general. You'll do anything—and eat anything—just to get through the day.
Q: Can getting too little sleep hurt you physically?
A: You bet. The negative effects of sleep deprivation don't stop with weight gain. People who chronically miss out on sleep are more likely to develop diabetes and high blood pressure. If the body never gets any downtime, it can have problems managing physical functions, such as blood sugar and blood pressure levels.
Q: I never sleep well. Do you have any advice?
A: First, get plenty of physical activity. Keep in mind that sleep rests both the body and the mind. So if you have been sedentary all day, your body does not feel much need for rest and you'll lie awake longer. But if exercise has made your body tired, sleep comes easily, restoring body and mind. A few push-ups or similar muscle-stressing exercises before bed can help. Be careful about aerobic activities, such as running, before sleep; they sometimes have the opposite effect, interfering with sleep.
If you are chronically sleep deprived, here are a few no-no's:
Caffeine. As much as one-quarter of the caffeine in a morning cup of coffee is still in your bloodstream 12 hours later. Everyone reacts to caffeine differently, so pay attention to how it affects you.
Alcohol. A glass of wine may lull you into slumber. But a few hours ater, alcohol converts to closely related chemicals, called aldehydes, which are stimulants that can wake you up well before dawn.
High-protein foods. If you're having a big bean burrito or other high-protein food, have it for lunch, not dinner. High-protein foods reduce your brain's ability to produce serotonin, a mood-regulating chemical that helps you sleep. Instead, emphasize starchier foods in the evening. They boost serotonin production in your brain and help you drift off to sleep when the time comes.
Finally, act like a kid. Most children sleep beautifully. They stretch and yawn, then lapse into sleep, and are practically unarousable until morning. If you are chronically wired, go through the same motions: stretch and yawn, even if you have to fake it. Do this a few times, and you'll find a normal sleep response soon follows.