According to Philip Cheng, Ph.D., clinical psychologist and research scientist at the Sleep Disorders and Research Center at Henry Ford Health, there is a direct link between too little or too much sleep and issues with weight management.
“It’s not a linear relationship, but a U curve,” he explains. “Many people who sleep too much can have weight issues, likely related to illness. But we also see that people who are sleep deprived – sleeping less than seven hours a night – are often overweight or obese.”
There are three logical reasons why:
- Sleep deprivation leads to increased appetite. “Sleep is restorative and provides energy. When people don’t get that restoration through sleep, the body may compensate by increasing hunger to refuel through caloric intake,” says Dr. Cheng. It’s a double whammy because the hunger is not for salad and sparkling water – it’s for high-fat, high-calorie, high-carbohydrate foods. “Not only do you feel hungrier, you crave the types of foods that make weight loss more difficult,” adds Dr. Cheng.
- People who are sleep deprived are less likely to be physically active. “Our bodies are tired and want to preserve energy, not increase output,” says Dr. Cheng. “When you have downtime, you’ll more likely want to ‘veg out’ on the couch rather than hit the gym.”
- Timing of food intake plays a key role in weight management. Eating late at night might also make weight loss more difficult. Our physiology operates on an internal clock, which means the effectiveness of digestion and metabolism varies throughout the day. “Your body expects sleep during the night, not food," says Dr. Cheng. "When we stay up late or wake in the night and eat, digestion is less efficient and food may be stored as fat rather than metabolized for energy." Sleeping less also leaves more time for late meals, leading to a fourth meal or heavy snacking at night.
“If you’re trying to lose weight, it could help to examine your sleep habits,” advises Dr. Cheng. “Getting enough sleep – seven to nine hours a night for healthy adults – should help support weight management. You’ll have more energy for exercise, and when you minimize late nights, you’ll probably eat fewer meals and calories. If you get adequate sleep, you’re less likely to be hungry and have cravings for high fat and high carb foods.”
Employees who work night shifts should preemptively make healthier choices. “Pack healthy foods so they are readily available during your night shift. This way, you’re less likely to give into temptations of the late night ‘greasy spoon’ or vending machine,” he says.
Get Light on Your Side
If you have trouble falling asleep in time to get seven to nine hours of rest, set your internal clock to an earlier time with light management. “Some people are naturally night owls, so going to bed early might not work well – you might end up just lying in bed until your body is ready for sleep,” says Dr. Cheng.
Dr. Cheng offers these tips to reset your internal clock:
- Prevent light exposure one to two hours before bedtime. Keep the lights low in the house. Any backlit screen that is close to your eyes can cause wakefulness, so don’t use computers, cell phones or iPads for one to two hours before bed. You can even wear sunglasses to trick your body into thinking it’s later.
- Expose yourself to bright light when you wake up and throughout the morning. Turn the lights up wherever you can.
“Light is the strongest signal to our circadian clocks," says Dr. Cheng. "Light management can be used to push or pull your circadian rhythm to your desired schedule, and make it easier to get that optimum amount of sleep.".
Dr. Philip Cheng is a clinical psychologist and sleep research scientist with Henry Ford Hospital in Detroit.