Your Secret Weight Loss Weapon

It’s no secret that exercising more and eating fewer calories can help you meet your weight-loss goal. But as it happens, there’s an even easier way to promote weight loss: Sleep more.

Of course, sleep gives you the energy to do things like hit the gym. But it supports your weight loss journey in other ways. After all, sleep loss affects your blood sugar, eating habits, and hormone levels which can make people crave sugary and carbohydrate-rich foods, says Kelly Glazer Baron, Ph. D., a neurology professor at Northwestern University and American Academy of Sleep Medicine sleep expert.

In fact, a 2012 study found that sleep deprivation for just four nights can actually change the way your fat cells function: when you sleep too little, your body becomes less sensitive to insulin, the hormone that helps control blood sugar. The result? Decreased energy and increased appetite.

When you’re free of fatigue, though, you’re much more likely to make smart choices–like ordering the egg-white omelet instead of the BLT, or doing a FitJourney workout video instead of hitting up happy hour. But nearly a third of American workers still sleep too little, according to a 2012 study by the U.S. Centers for Disease Control and Prevention. After all, it can be hard to hit the hay at a reasonable hour when more seductive options–like Facebook or the next episode of Homeland–constantly vie for your time.

Even if you abide by a strict bedtime, excess weight can impact the quality of your sleep. Being overweight makes you more susceptible to sleep apnea, a sleep disorder characterized by difficulty breathing while you sleep. One remedy for sleep apnea is weight loss–but it’s a difficult feat when poor sleep leaves you fatigued. An estimated 50 to 70 million American adults suffer from sleep apnea or another sleep disorder, according to data from the Centers for Disease Control. If you snore or regularly wake up feeling groggy, ask your doctor about treatment options to prevent your body from suffering just as much as people who don’t spend enough time in the sack.

How Much Sleep You Need

According to the National Sleep Foundation, everyone needs a different amount of sleep. That said, a University of Chicago study found that among dieters who lost the same amount of weight, those who slept less lost more fat-burning lean muscle mass, while those who slept longer lost more fat. In other words, more sleep could help you shed the stuff you don’t want (like love handles) and keep the stuff you do (like defined upper arms). Still, it’s possible to sleep too much: a American Cancer Society survey of over 1 million adults found that people who sleep seven hours were less likely to die during a six-year period than people who sleep less–or more. So don’t overdo it–just figure out how many hours of shut-eye you need.

“A good way to tell how much sleep you need is to see how much you need to feel rested during the day. Or if possible, look at how much you sleep [per night] after two weeks of vacation,” says Baron.

Then, try to set a consistent bedtime and wake time every night. And if you must skimp on sleep during the workweek? Don’t try to double up on weekends. According to Baron, that could make your Monday-morning wake up call a real pain in the butt. Instead, extend your regular sleeping hours by 15 to 20 minutes on each end. “This increase of 30 to 40 minutes can really make a difference if you’re sleep deprived,” says Baron. Plan B: Nap for that length of time when you can.