Does Getting Less Sleep Make You Eat More?
By Elisa Zied, MS, RD, CDN
It’s no surprise that so many of us fail to get enough sleep on a regular basis to meet our needs. According to several recent studies, not getting enough zzz’s has become pervasive in America, with a substantial jump over the last three decades. One recent governmental study estimated nearly one in three working adults in America sleep for less than six hours a night.
Of course it’s inevitable that our sleep will be shortened or disrupted at least once-in-a-while—especially for those of us who are parents, if we have a demanding boss, or when enjoy a late night out with friends or a significant other. But while losing sleep from time to time can certainly sap our energy, make us feel sluggish, and make it more of a challenge to concentrate whether at home or at the office, not getting enough zzz’s on a regular basis can have more far-reaching health and other effects, and make it tough—if not impossible—to maintain a healthful body weight, in large part because it can make us eat more.
In a new article published in the October 2012 issue of the Journal of the Academy of Nutrition and Dietetics, researchers reviewed 18 original intervention studies published between 1996 to 2001 to see how being partially sleep deprived—sleeping four to six hours a night—affected energy balance and body weight. Specifically, they wanted to see how partial sleep deprivation affected hormone levels that, in turn, could affect energy intake and body composition (lean muscle and body fat). They also looked at how not sleeping enough could affect energy expenditure.
After analyzing all the studies, the researchers identified a set of patterns, especially those that involved certain hormones. For one, they found reduced insulin sensitivity. Normally, the hormone insulin usually rises after a meal in order to transport glucose (from the meal) into body tissues; then, insulin levels usually go down. But when there’s insulin resistance, there’s an inability to send glucose into body tissues and therefore insulin levels stay elevated.
The researchers also found increased levels of ghrelin. According to registered dietitian Marjorie Nolan Cohn, author of an upcoming book on the subject, “Ghrelin is your primary hunger hormone. When you’re hungry, ghrelin is released from the lining of your stomach and circulates through your blood to your brain to let you know you’re physically hungry.” But Nolan Cohn says ghrelin affects more than just hunger. “It also functions within the pleasure/reward center of the brain, plays a role in memory formation, immune function, and even in sleep,” says Nolan Cohn.
Along with higher levels of both insulin and ghrelin, the researchers found lower levels of the hormone leptin. Normally, leptin reduces appetite. Decreased levels can therefore contribute to increased appetite and energy intake.
Although we need more data to fully understand how limited sleep affects calorie intake, energy expenditure, and body composition—and the specific effects of hormones on those variables—Rachel Begun, MS, RD, spokesperson for the Academy of Nutrition and Dietetics, says, “This study shows that getting enough sleep on a consistent basis—and not just focusing on diet and exercise—may prove to be an important part of the weight management equation."
To help you get a better sleep, Begun recommends sticking to a regular sleeping pattern. “It’s important to go to bed and wake up at nearly the same time every day, including weekends,” she adds. She also suggests turning off all screens—televisions, computers, cell phones, and tablets— at least one hour before bed, as blue light can keep you up. You’ll also find some helpful diet and fitness tips to help you sleep in my recent post for US News and World Report’s Eat + Run blog.
But what if it’s too late—what should you do when you haven’t slept much or well and need to get through the day without sabotaging your healthy eating habits?
“If you do feel hungrier than normal, eat foods rich in protein and fiber with all meals and snacks; these nutrients keep you satisfied longer and keep hunger at bay,” says Begun, She also recommends avoiding alcohol and caffeine too late in the day to help you get back on a healthy sleep track. Finally, Begun warns against going to bed too hungry or too full. “Feeling satisfied but not stuffed at bed time can help you fall asleep easier,” she says.
On an average night, how many hours of sleep do you get? How well do you sleep?
Elisa Zied, MS, RD, CDN, is a nationally recognized registered dietitian and award-winning author of "Nutrition At Your Fingertips," "Feed Your Family Right!," and "So What Can I Eat?!." She is also a past national media spokesperson for the Academy of Nutrition and Dietetics. For more information, go to www.elisazied.com. Sign up for the free weekly ZIED GUIDE™ newsletter for nutrition tips and news you can use (go to right side of home page at elisazied.com). Follow Elisa on Twitter/elisazied and on Facebook.