does sleeping late and waking up late cause weight gain?

Does Sleeping Late Make You Gain Weight?

(Last Updated On: January 2, 2023)

When you go to bed is linked to body mass index (BMI), so night owls are often heavier than early birds.

The later we stay up, the more likely we will consume high-calorie foods. When we’re tired, our willpower to resist junk food wilts, leading to passive eating, such as snacking on potato chips while watching TV. When paired with a slower metabolism overnight, it results in weight gain.

Even if you’re careful about how many calories you consume at night, late bedtimes can still lead to weight gain. The human body is governed by circadian rhythms, with hormones dictated by them. So, a reliable sleep routine can lead to a healthy BMI.

Does Sleeping Late Make You Fat?

It’s an oversimplification to claim that staying up causes weight gain. As the journal Sleep explains, there’s a potential link between imperfect sleeping patterns and a higher BMI.

It’s what we do while we’re awake long into the night that impacts our weight for the worse, not just the act of staying awake. Often, a late night and additional calorie consumption go hand in hand.

We burn calories while we sleep, albeit not as quickly as during the day. If we’re asleep, that’s not a problem because we aren’t consuming calories to replace those that are burned off. Technically, we’re losing weight by dozing.

If we’re awake, there’s always the possibility of eating. As the metabolism at night is so much slower, junk food is more harmful after dark. Unfortunately, junk food sometimes feels irresistible late at night.

Passive Eating

You’re relaxing on the couch after a long day at work. You pour a glass of wine or open a beer, and one glass or bottle turns into two. You can’t face cooking, so you order a pizza. You treat yourself to popcorn or potato chips while watching TV, which is known as passive eating.

We eat without thinking, not even stopping to enjoy the process. As per ISRN Obesity, passive eating often leads to food addiction, as we rely on these midnight feasts without realizing it.

best time to sleep to lose weight

.Junk Food Cravings

According to Nutrients, poor food choices at night are often linked to poor health and weight gain. Maybe if we ditched the junk food and replaced it with carrot sticks and hummus in the evening, we’d have fewer issues.

That’s possible, though such a snack would likely still lead to us consuming more calories than we burn. Either way, it’s an unlikely turn of events. The human brain craves sweet and salty junk foods at night.

You’ll likely be subjected to countless food-related advertising. If you’re not eating already, that may tempt you into snacking.

Unfortunately, your willpower is likely to be low at this point. Studies suggest that fast-food consumption rises sharply after 8 pm, while fresh fruit and vegetables are increasingly left eaten. The more tired we are, the likelier we are to cave into temptation.

Night Eating Syndrome

Night-eating syndrome (NES) is a clinically recognized eating disorder.

Somebody living with NES will have little appetite in the morning and afternoon, desiring to eat most of a day’s calories after a traditional dinner.

NES usually causes people to wake up at night, often multiple times, to raid the fridge. This will become a compulsion, preventing somebody from returning to sleep until they’ve eaten. 

Obesity is a contributing factor to NES. While the condition only impacts around 1% of the population, there’s a 1 in 10 chance that somebody living with obesity also has NES.

This becomes a vicious circle because poor sleep can eventually lead to obesity.

Does Sleeping Too Much Cause Weight Gain?

Having established that failing to get enough sleep will lead to weight gain, we should ask if the opposite is true. What happens if we sleep too much? Will that also lead to poor health?

The biggest problem that oversleeping poses to BMI is its impact on metabolism. If you spend too much of your morning in bed, you’ll burn fewer calories; if you sleep until late, the deficit remains.

You’re missing out on an opportunity to get out into the world and burn some calories. The human body works in cycles; if you’re not careful, it’ll be evening again before you’ve woken up.

That opens the risk of repeating the previous night’s mistake of staying up late and eating all the while. This could become normal if you don’t change your rest habits and develop better sleep hygiene.

How Does Bad Sleep Affect Your Metabolism?

Insufficient sleep, potentially caused by eating late at night and struggling with nocturnal digestion, will leave you feeling lethargic in the morning. This will slow down your metabolism, burning off calories slower than ever.

This will have a variety of knock-on effects. You’re less likely to be inclined to exercise and burn calories, and your willpower to resist junk food will continue to remain low. You’re likely to eat poorly, consume excessive calories, and struggle to sleep again later that night.

If you feel sluggish, resist the urge to take a nap. If you must get extra rest, restrict your daytime doze to a power nap of thirty minutes or less. Nap early, too. The metabolism is most active between 4 – 6 pm, so aim to be awake and ready to eat by then.

The European Journal of Clinical Nutrition explains how longer naps during the day can significantly impact metabolism. You’ll be placing your health at risk by attempting to catch up on lost sleep in the afternoon. Hold out until the evening and get an early night.

Another significant connection between poor sleep and BMI comes from hormone production. If you’re not sleeping well at night, four primary hormones in the body – all linked to your BMI – are impacted.

Leptin and Ghrelin

Leptin is a hormone created by the small intestine. This hormone is released when we feel full, telling the brain that it’s time to stop eating. Leptin also regulates energy and inhibits hunger pangs, so you don’t feel compelled to eat further.

The body stops creating leptin when we stay up beyond what feels like a natural bedtime, and that’s how we end up passive eating. There’s no reaction in the body to say that it’s time to put the bag of chips down.

Leptin is a red light for eating, while grehlin is a green light. Grehlin starts in the stomach, telling the brain it’s time to eat. Essentially, grehlin could be called the “hunger hormone.”

Unlike leptin, the body never stops creating grehlin, no matter how tired we feel. As a result, we lose all sense of perspective surrounding food at night, as we eat without ever feeling full.

The human metabolism is considerably slower when we’re tired and it’s late at night. Put all of this together, and the reason for weight gain is pretty apparent.

One hormone encourages you to eat while another neglects to tell you not to, so your metabolism is incapable of burning off the calories at the rate you’re consuming them. If you’re staying up late with regularity, weight gain will steadily creep in.


Another impact of leptin failing to perform its function is the enhanced risk of diabetes. The Journal of Clinical Endocrinology & Metabolism explains that just one night of disturbed or low-quality sleep results in insulin resistance.

If we’re up too late, the body rejects naturally produced insulin and can’t extract glucose from the blood. Then, more insulin is created, so the body can become flooded with more insulin than it can process. 

Thankfully, blood sugar levels naturally regulate while we slumber. As a result, healthy sleeping patterns ease worries about insulin production. If you’re struggling with pre-diabetes symptoms, better sleep will be among the first lifestyle changes prescribed.


Staying up late often triggers a stress response in the brain, even if unintended.

If you’re a natural night owl, this may not be the Fighting natural tiredness that often forces the body to release cortisol (the stress hormone).

When the body experiences heightened cortisol levels, it starts to store fat. Instead, the body converts soft tissue into energy to remain awake. The more this continues, the more fat will stay in the body.

A compulsion to snack on junk food late at night will add to these fat reserves. Displeasure with physical appearance and condition, paired with the exhaustion that accompanies poor sleep, will create more stress. Naturally, this means more weight gain.

does sleeping late and waking up late cause weight gain?

What is the Best Time to Sleep to Lose Weight?

If you’re aiming to bring weight loss into your sleep regime, you’ll need to ensure that you enjoy a minimum of seven-and-a-half hours of slumber per night. If an alarm is set for 7 am, you should be under the covers by 11.30 at the latest.

If you can retire a little earlier, that’s even better. Give your stomach three hours to recover from eating a meal, and consider going to bed. If you finish eating at 7 pm, start your bedtime routine at 10 pm.

This may take a little getting used to, especially if you’re a night owl. You can train yourself to accept and even embrace an early night. Much like avoiding nocturnal calories, it will require perseverance and willpower.

Good Sleep Habits to Aid Weight Loss

Catching an early night alone won’t lead to weight loss, and you’ll need to work on your diet and other lifestyle elements. There are tips related to sleep that will help you shed pounds, including:

  • Brush your teeth after eating, as this will suppress your appetite.
  • Exercise during the day before your evening meal, so you’re likelier to feel sleepy at night.
  • Drink tap water to stave off hunger pangs, but don’t consume too much liquid close to bedtime, as you’ll have to wake up to go to the toilet.
  • Keep calm. The more stressed you become, the more cortisol your body will create and the fewer calories you’ll burn overnight.
  • Steadily reduce screen time, especially if you’re prone to snacking while watching TV. Find other, less passive ways to occupy your time in the evening.

Above anything else, maintain a reliable routine. Set the alarm to remind you to go to bed if needed. After a while, this will become second nature, and what was once an early night becomes bedtime, making mornings more appealing.

The evidence is clear; the later we go to bed, the higher the risk of gaining weight. If you’ve tried countless fad diets and gym workouts but still can’t shed those last stubborn five pounds, try getting a few early nights, as this could make all the difference.