Does poor sleep cause weight gain? What the research shows

Poor sleep can contribute to weight gain, mostly by making you hungrier and more likely to eat more. Short sleep shifts the hormones that control appetite, and a 2022 trial found that when short sleepers slept longer, they ate fewer calories without trying. Sleep isn't the only factor in weight, but it's a real one, and it connects with snoring in both directions.

Does poor sleep cause weight gain?

Poor sleep is linked to weight gain, and newer trials suggest the link is at least partly causal. The strongest early evidence came from population studies. A 2008 meta-analysis in Sleep pooled data from 634,511 people around the world and found short sleepers had higher odds of obesity: a pooled odds ratio of 1.55 in adults and 1.89 in children. The authors were careful to note that causal inference was difficult, because those studies couldn't fully rule out other explanations.

That's why the trials matter. The best-known is a 2022 randomized clinical trial in JAMA Internal Medicine. It enrolled 80 adults aged 21 to 40 with overweight, a BMI of 25 to 29.9, who habitually slept less than 6.5 hours a night. Half received an individualized sleep hygiene counseling session aimed at extending their time in bed to 8.5 hours. The other half carried on as usual. Nobody was given a diet or exercise plan.

The sleep extension group slept about 1.2 hours more per night than the control group, and ate about 270 fewer calories a day. Their energy use didn't differ significantly from the control group, so over the two-week intervention they lost about 0.48 kg while the control group gained about 0.39 kg, a difference of 0.87 kg. The researchers worked out intake objectively rather than asking people what they ate: they measured energy use with a method called doubly labeled water and tracked changes in body energy stores with daily home weigh-ins and body composition scans.

The authors also noted that limiting the use of electronic devices before bed appeared to be a key change for participants. It's one short trial in a specific group, but it's a notable result for something as simple as going to bed earlier.

How does lack of sleep affect hunger hormones?

Lack of sleep pushes up the hormone that drives hunger and pulls down the one that signals fullness. The NHLBI explains that good sleep supports a healthy balance of ghrelin, which makes you feel hungry, and leptin, which makes you feel full. When you don't get enough sleep, ghrelin goes up and leptin goes down, and you feel hungrier than when you're well rested.

A small but well-known 2004 study in Annals of Internal Medicine showed this directly. Twelve healthy young men spent two days with restricted sleep and two days with extended sleep, under controlled calorie intake and activity. After short sleep, leptin fell by 18%, ghrelin rose by 28%, hunger went up by 24% and appetite by 23%. The appetite increase was strongest for calorie-dense, high-carbohydrate foods, at 33% to 45%.

The same pattern showed up in a larger group. A 2004 study in PLoS Medicine looked at 1,024 adults in the Wisconsin Sleep Cohort. Among people sleeping less than 8 hours, which was about three quarters of the group, BMI rose as sleep fell. Habitual sleep of 5 hours versus 8 was linked to 15.5% lower leptin, and 5 hours of measured sleep versus 8 to 14.9% higher ghrelin.

Can poor sleep make dieting harder?

Poor sleep can make a diet less effective, at least in the short term. In a 2010 study in Annals of Internal Medicine, 10 adults with overweight followed 14 days of moderate calorie restriction twice: once with 8.5 hours in bed each night and once with 5.5 hours.

They lost weight both times, but the kind of weight differed. With short sleep, the share of weight lost as fat fell by 55%: 0.6 kg of fat compared with 1.4 kg on the longer sleep schedule. At the same time, loss of fat-free mass, which includes muscle, rose from 1.5 kg to 2.4 kg. Participants also reported more hunger on short sleep.

It was a small study and only two weeks long. But it suggests that if you're cutting calories, short sleep may leave you hungrier and losing less fat for the same effort. Our guide to how much sleep adults need covers how to tell if you're getting enough.

How are snoring and weight linked?

Snoring and weight are linked in both directions: extra weight makes snoring more likely, and loud snoring can disrupt the sleep that keeps appetite in check. The NHS says you're more likely to snore if you're overweight, and its first suggestion for snoring is to lose weight if you're overweight. Cleveland Clinic says snoring and sleep-related breathing disorders are more common in people with overweight or obesity.

Weight changes show up in breathing at night. In a 2000 study in JAMA, researchers followed 690 adults in Wisconsin over four years. Compared with stable weight, a 10% weight gain predicted about a 32% increase in the apnea-hypopnea index, a measure of breathing problems in sleep. A 10% weight loss predicted about a 26% decrease. A 10% gain also predicted a sixfold increase in the odds of developing moderate to severe sleep-disordered breathing.

The other direction runs through sleep quality. Cleveland Clinic describes snoring as a common condition that can disrupt your sleep, and says most of its risks relate to sleep deprivation and sleep apnea, listing obesity and hormonal imbalances among them. It also notes that snoring can keep a partner from getting a good night's sleep. We cover the details in weight loss and snoring and can sleep apnea cause weight gain?.

How can you sleep better to support a healthy weight?

The most useful step is giving yourself enough time in bed, then protecting the quality of that sleep. The NHLBI lists 7 to 8 hours a day for adults, and notes that NHLBI-funded research found adults who regularly get 7 to 8 hours a night have a lower risk of obesity and high blood pressure.

Practical ways to get there:

• Set a consistent bedtime that allows 7 to 8 hours before your alarm, and keep weekends close to weekdays.
• Put devices away before bed. The authors of the 2022 trial noted that limiting electronic devices appeared to be a key change for participants.
• Avoid heavy meals and alcohol close to bedtime, as the NHLBI suggests. There's more in our guide to snoring after a big meal.
• Keep caffeine to earlier in the day; see caffeine and sleep.
• Sleep on your side if you snore on your back, as the NHS suggests.

If snoring or mouth breathing is breaking up your sleep, it's worth working on directly. The NHS lists nasal strips or dilators for blocked or narrow nasal airways, and devices that keep the mouth closed for a mouth that falls open. Cleveland Clinic says nasal strips can help keep your nasal passages open. Some people use the Titan Sleep System, which pairs nasal strips with mouth tape, to make nighttime breathing more comfortable. It isn't a weight loss tool, and Titan's products weren't used in any of the studies above. Check you can breathe comfortably through your nose with the nose test first. We don't recommend mouth tape for children.

When should you see a doctor about sleep and weight?

See a doctor if you snore loudly and also feel sleepy in the day, or if someone has seen you stop breathing at night. The NHS says to see a GP if you feel sleepy during the day, your breathing stops and starts while you sleep, or you make gasping or choking noises, which can be signs of sleep apnea. Gaining weight while those signs build is a good reason to get checked, and our page on sleep apnea warning signs explains more.

It's also worth seeing a doctor about unexplained weight gain, a nose that's always blocked, or ongoing trouble sleeping. If you're pregnant, ask a clinician before trying any snoring product.

Our pick (paid partner): Titan Sleep System

For people whose snoring or mouth breathing is disturbing their sleep, our pick is the Titan Sleep System. To be clear, the research above is about sleep, not about Titan's products, which weren't used in any of these studies. We haven't tested or ranked products ourselves. This is our recommendation for more comfortable breathing at night, not a weight loss tool.

Titan says the system combines TitanAir Nasal Strips and Titan Bamboo Silk Mouth Tape as one nightly routine. It describes the strips as drug-free external nasal dilators with flexible spring-loaded bands, placed just above the flare of the nostrils on the soft part of the nose rather than the bony bridge. The tape is a bamboo silk strip worn horizontally across the lips, and Titan suggests 20 to 30 minutes of daytime practice before the first night.

Titan says every batch is third-party tested and certified PFAS-free, and its 30-night guarantee refunds you if your sleep isn't better after 30 nights. That gives you a month to see whether the system fits your nightly routine.

Read next

• How weight affects snoring, and whether losing weight helps
• Does lack of sleep make snoring worse?
• How much sleep do adults need?

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.