Unless you've been sleeping under a rock (pun intended), you already know that sleep deprivation is directly linked to weight gain. Studies have shown that when we don't get enough zzz's, we're more likely to gain weight.
Dr. Michael Breus, SleepScore Labs advisory board member and author of The Sleep Doctor's Diet Plan, said, "Lack of sleep has been linked to both increased calorie consumption and reduced energy expenditure — that means more calories in and fewer calories out."
The National Sleep Foundation recommends seven to nine hours of sleep for adults, but Dr. Breus says a third of working adults are sleeping no more than six hours each night. So if you need another reason to hit the hay, here are five ways sleep can help you shed unwanted pounds.
1. It Keeps Your Hunger Hormones in Check
In order to understand how sleep influences your appetite, it's important to know how your hunger hormones — leptin and ghrelin — work. Leptin is the hormone that signals to your brain that you're full. It also helps your body maintain a healthy weight by regulating how it uses energy. On the other hand, ghrelin is the hormone that says you need to eat; it tells your body to stop burning energy and to start storing it as fat.
Lisa Samuels, RD, founder of The Happie House, said, "Being well-rested gives our hormones and cycles a chance to reset so that everything is working properly in the morning. The hunger and satiety hormones are at work, allowing people to eat mindfully."
2. It Puts Stress to Bed
When you stay up late at night working, your cortisol levels skyrocket. Cortisol is the stress hormone that helps control blood sugar and aids in metabolic functions. Elevated cortisol levels signal to your brain that it needs more energy to carry out activities. As a result, you have the sudden need for sweets and snacks. "You are less reactive to stress when you're not sleep deprived," Dr. Breus said. Because you're well-rested, your hormone cycles aren't out of whack, and you're able to eat more mindfully.
3. It Shows Your Blood Sugar Levels Who's Boss
Insulin is another hormone that is a game changer for weight loss. It moderates blood sugar and carries glucose from the blood into the cells of muscles, the liver, and other organs. Forgoing more snooze time causes you to develop insulin resistance because your body isn't able to use the hormone efficiently. Dr. Nate Watson, director of the University of Washington Medicine Sleep Clinic and SleepScore Labs advisory board member, said, "Sleep helps your body have normal insulin sensitivity, so your body processes glucose effectively and avoids storing much of it as fat."
4. It Promotes Greater Calorie Burn
If you're an early bird who likes to work out first thing in the morning, you're in luck. Research shows that working out can get your metabolism humming, so you burn more calories and fat throughout the day. "Exercise is a wonderful tool that helps us decrease stress and boost our metabolism," Samuels said. But if you're an evening exerciser, Samuels recommends working out two to three hours before bedtime to ensure that it doesn't disrupt your sleep cycles.
5. It Restores Your Body
During sleep, you're fasting — not consuming any food or water — so your body is rested, replenished, and ready to take on whatever the next day brings. If you ever stood on a scale in the morning and realized that you weigh a few pounds less, that's because your body works to restore itself while you snooze. "In the morning, all of the water and food has been absorbed into the system. While breathing at night, we lose about a liter of water. This is probably where the most weight loss happens," Dr. Breus explained. As the day goes on, your weight fluctuates based on the food you eat, the beverages you drink, and the way your body responds to stress. So if you want to truly see the best version of yourself, it's after you've slept a full night. "The long period without food or water, plus having everything be digested, rested, and presumably excreted, is the reason we're at our true weight first thing in the morning," Samuels said.