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How Losing Just an Hour of Sleep a Night Could Affect Your Weight
Researchers are finding that sleep may play a bigger role in weight management than many people realize, even when sleep loss is relatively mild
Published August 19, 2026
When most people think about unwanted weight gain, diet and physical activity often come to mind first. But there’s another part of the puzzle that gets far less attention: sleep. “There’s a lack of understanding of how much sleep affects weight,” says Taruj Ali, chief medical officer at sleep and metabolic clinic SOMOS Healthand medical director of sleep at Mary Washington Health System. “Of course, diet and exercise are important. But sleep is part of the trifecta for weight management.”
And while it’s easy to assume only extreme cases of sleep deprivation would make a difference, a new six-week trial published in Annals of Internal Medicinefound that losing around an hour of sleep each night may be enough to nudge body weight upward
The findings come as researchers are questioning long-held assumptions about weight loss. Recent studies have found that exercise may burn fewer calories than once thought, and that eating less food can often make weight loss harder. Now, this new study adds evidence that sleep may be another important part of the equation. Here’s what scientists know about the relationship between sleep loss and weight gain
The Effects of Losing About an Hour of Sleep
Researchers at Columbia University Vagelos College of Physicians and Surgeons studied 95 adults who normally got around at least seven hours of sleep a night. Participants were asked to delay their usual bedtime by 90 minutes while waking at the same time. They maintained this mildly sleep-deprived schedule for six weeks, ultimately sleeping about 80 minutes less per night
What makes the study particularly interesting, Ali says, is that the sleep loss more closely resembles what many people experience in everyday life. According to the Centers for Disease Control and Prevention (CDC), nearly 35 percent of Americans get less than seven hours of sleep a night. Many previous sleep-deprivation experiments have subjected participants to much more extreme sleep loss over relatively short periods in a lab setting. The results could suggest that the everyday sleep loss millions of people experience may be enough to shift the body’s energy balance over time slowly.
(How do a few nights of bad sleep become insomnia?)
But there are limits to what six weeks can tell us. The study wasn’t designed to determine whether gaining a pound over six weeks would translate into steady weight gain over months or years. Brian Wojeck, weight management and sleep disorder specialist and assistant professor of medicine at Yale University, says that’s especially important because many of the patients he treats aren’t mildly sleep-deprived for just six weeks—they experience disrupted or insufficient sleep chronically
“This study gives us a glimpse into what might be happening, but the truth is for many of our patients, it’s not just six weeks. It’s all the time. Most of our patients that we see in a sleep clinic are chronically sleep-deprived,” he says. Whether the effects accumulate over months or years remains an open question
The study also excluded people with certain diagnosed conditions, including sleep disorders and diabetes. Ali says that leaves open the question of whether the effects of sleep restriction might differ in people already living with those conditions
How Could Sleep Loss Lead to Weight Gain?
There probably isn’t a single explanation for why sleeping less can affect weight. Wojeck says research suggests sleep deprivation can disrupt systems that regulate hunger and appetite, namely ghrelin (which signals hunger) and leptin (which tells the brain when you are full)
But researchers are still working out exactly how those hormonal changes contribute to weight gain. “We don’t understand it completely,” says Wojeck. Still, “patients get hungrier and, on average, gain weight when they are sleep-deprived, at least initially,” he adds
(Does eating close to bedtime make you gain weight? It depends.)
Sedentary time also increased for study participants, although Wojeck thinks it’s unlikely that this factor alone would result in weight gain
Sleep and weight can also become a vicious cycle. Excess body weight is a major risk factor for sleep apnea, a condition in which breathing repeatedly stops and starts during sleep. As body weight increases, Wojeck says that sleep apnea can become more severe, potentially disrupting sleep even further
Why Sleep Should be Part of Weight Management
People trying to manage their weight should, when possible, maintain a regular bedtime routine and get at least seven hours of sleep consistently, Ali says. That extra time may matter more than people realize, particularly because mild sleep deprivation can be easy to normalize. Someone sleeping five or six hours a night may not think of themselves as sleep-deprived, but they are
(When you go to bed may matter more than how long you sleep.)
Of course, getting enough sleep isn’t always as simple as going to bed earlier. People who consistently wake up exhausted, snore heavily, or experience disrupted sleep may have an underlying sleep disorder such as sleep apnea and should talk to a healthcare provider
For both Ali and Wojeck, the study’s biggest takeaway isn’t that sleeping more is a magic bullet for weight loss. Instead, consider sleep alongside the other habits that influence weight and metabolic health
Hannah Singleton is a New York–based freelance journalist and editor covering health, wellness, and fitness.
