The old calories-in-calories-out model of weight management relies almost exclusively on diet and exercise. But it turns out there’s some good science behind a third strategy: getting more sleep.

“If you wonder if there's any role for sleep in weight regulation … the short answer is yes,” said Esra Tasali, MD, a sleep specialist at the University of Chicago Medicine, at a 2025 international sleep conference in Singapore. Evidence shows that sleep duration and quality can change your metabolism, appetite, and hormone levels.

The Physiological Effects of Sleep Deprivation

When you don’t get enough sleep, your brain turns up its “reward center,” which triggers what experts call “hedonic eating” — eating for pleasure, not because you’re hungry. This generally involves foods high in fat, sugar, and salt.

Sleep deprivation also interferes with hormones. Exhaustion causes your body to secrete more ghrelin — the “hunger hormone” — while lowering levels of leptin, which helps you feel full. This imbalance makes you feel hungrier and drives you to eat more. 

Another key factor: You need more energy to stay awake. About 70% of your calorie intake goes toward your body’s most basic functions, like breathing and staying warm, said Tasali. During sleep, when your muscles relax and your core temperature falls, this calorie need drops by 20% to 30%. “So when we force ourselves to stay awake, that comes with an energy cost.” 

There is also the energy we use to eat and digest, called the thermic effect of food. “But when we sleep, we don’t eat, so that is absent,” Tasali said. 

You must eat more to fuel these extra tasks — and late-night snacking is typically not the healthiest type of eating. 

Just 30 Additional Minutes of Sleep Can Help

Tasali and colleagues have shown that getting as little as half an hour more sleep on a regular basis can aid weight loss. Experts call this strategy “sleep extension.”

Tasali’s team studied 80 people with overweight who slept less than 6.5 hours. Half of these people were assigned to sleep longer, and the rest to continue sleeping as usual. After two weeks, those who slept longer (1.2 hours, on average) consumed 270 fewer calories.

“They reported to be less sleepy and more alert, but also they reported less overall appetite and less desire for high-calorie foods,” Tasali said. The study revealed that calorie consumption fell with just 30 minutes of additional sleep.

Consuming 270 fewer calories each day may not seem consequential, but it adds up. “When we think about weight gain, even as little as 100 kilocalories of excess calories per day can lead to weight gain over long periods of time,” Tasali said.

Sleep can also affect the type of weight loss. A 2010 study found that sleep-deprived people who lost weight shed less fat and more muscle than those who got enough sleep.

Other larger-scale studies zoom out to show how sleep deprivation relates to overall body weight. In a 2020 study, researchers analyzed data from more than 120,000 adults wearing sleep trackers and found shorter sleep time was linked to higher body mass index. 

Crucial Connections

In addition to sleep duration, other factors like sleep timing, quality, and regularity are also important, Tasali said.

“The importance of adequate sleep in maintaining a healthy weight remains crucial for preventing obesity,” Tasali concluded at the meeting. “A healthy sleep could be a game changer for weight regulation.”