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Do you want to improve your diet? Try to sleep better.

In recent years, researchers have found that our sleep patterns strongly influence the amount and types of food we eat and even whether we gain or lose body fat. Sleep loss can trigger brain and hormonal changes that stimulate food cravings, which can cause us to eat more calories, especially junk foods high in fat and sugar.

If you’re one of the millions of adults suffering from chronic sleep deprivation, research suggests that sleeping just an extra hour each night can lead to better eating habits and may even help you lose weight.

For many people, a good night’s rest is hard to come by. Sleep experts say the average adult should sleep at least seven hours a night. Still at least 1 in 3 adults regularly fails to get enough sleep. Some people skimp on sleep so they can stay up late to work or surf the web. Millions of adults also struggle with conditions that disrupt their sleep, such as chronic insomnia, sleep apnea or restless leg syndrome.

Understanding the factors that influence your daily food decisions is an essential step in improving your overall health. Every Tuesday, Eating Lab will explore the different biological and cultural forces that influence our eating habits. And the quality of your sleep at night, according to numerous studies, is a big one.

Why poor sleep can make you eat more

Research shows, for example, that consistent poor sleep can pave the way for weight gain. Studies have shown that for women, a a few nights of short sleep reduce GLP-1 levels, a hormone that signals satiety. In men, sleep loss leads to a spike in ghrelin, a hormone that stimulates hunger.

At the same time, sleep deprived people experience changes in their brain activity. Studies show that when a person is sleep deprived, the region of the brain involved in pleasure seeking and reward reacts more strongly to junk food like candy, donuts, and pizza, creating more powerful cravings to indulge in fattening foods. And the loss of sleep causes a decrease in activity in other parts of the brain that regulate food intake, making it more difficult for people to exercise self-control.

“The overwhelming evidence is that when you restrict sleep, people eat more,” said Marie-Pierre St-Onge, associate professor of nutritional medicine at Columbia University Irving Medical Center and director of the Sleep Center of Excellence at Columbia.

Last year, a group of researchers analyzed data from 36 studies which included several hundred thousand participants. They found that people who regularly slept less than seven hours a night had a 26% higher risk of developing obesity compared to people who got the recommended amount of sleep.

One caveat is that this analysis only showed an association between poor sleep and weight gain. To better understand the relationship between sleep and diet, scientists have conducted clinical trials in which they recruit healthy adults and monitor their eating habits while limiting their nighttime sleep.

A trial found that when people just slept 5.5 hours a night over a two-week period, they consumed an additional 300 calories a day, mostly snacks like pretzels, cookies, chips, ice cream and candies. St-Onge analyzed many of these trials and found that, on average, people eat between 300 and 550 calories more on sleep-deprived days compared to days when they can sleep seven hours or more.

An “expansion” of abdominal fat

Perhaps most strikingly, sleep deprivation seems to promote a particularly dangerous form of body fat.

In a study published earlier this year in the Journal of the American College of Cardiology, scientists found that when healthy adults sleep only four hours a night over a two-week period, the participants not only ate more and gained weight, but they also experienced an “expansion” of their abdominal fat, specifically the visceral fat that surrounds internal organs such as the kidneys, liver and the intestines.

Having high levels of visceral fat increase your risk of developing heart diseasetype 2 diabetes and several cancers.

How to improve your diet with better sleep

The good news for those of us who suffer from chronic sleep deprivation is that it is possible to undo the damaging effects of sleep loss on our diet and waistline. In a study published earlier this year in JAMA Internal Medicine, scientists recruited 80 overweight adults who regularly slept an average of about six hours per night. A group was advised on how to get more sleep. The other group received no additional information and served as a control.

An essential part of the counseling sessions was train people to stay away from their smartphones and electronic devices as they were about to go to bed. “We were basically teaching people how to live without their electronics too close to bedtime,” said Esra Tasali, study author and director of the University of Chicago Sleep Research Center.

The researchers then followed the groups for two weeks. They found that people in the counseling group increased their sleep by about 1.2 hours per night and reduced their food intake by 270 calories per day, even though they were not receiving any dietary counseling. They also lost some weight compared to the control group, and they reported feeling better and having more energy.

“They said they understood that it was normal not to answer all text messages an hour before bedtime,” Tasali said.

St-Onge at Columbia said everyone should generally aim for around seven hours of nighttime sleep. You’ll know if you’re getting enough sleep if you wake up well-rested and aren’t constantly tired and fatigued.

The key is to turn off your devices and go to bed at a reasonable time. “Some people might only need six hours of sleep, and for others, six and a half hours,” St-Onge added. “But I doubt anyone is good with just five hours of sleep.”

Do you have a question about healthy eating? E-mail [email protected] and we may answer your question in a future column.