does sleeping late and waking up late cause weight gain?

Does Sleeping Late Make You Gain Weight?

Bedtime is correlated to body mass index (BMI), so night owls often carry more weight than early risers.

The later we stay up, the likelier we are to eat high-calorie, fatty foods. When tired, our willpower to resist junk food diminishes, leading to passive eating, such as snacking on potato chips while watching TV.

Coupled with a slower overnight metabolism, it results in weight gain and obesity. Even when we’re careful about calorie consumption, late bedtimes can cause us to pile on the pounds.

The human body is governed by circadian rhythms, with hormones like melatonin being controlled by them. A reliable, consistent sleep routine can help regulate your 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 late-night sleeping patterns and a higher BMI.

It’s what we do while awake long into the night that negatively impacts our weight, not just the act of staying awake. Often, a late night and extra 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 sleeping.

If we’re awake, we may eat. As our late-night metabolism is much slower, junk food is more detrimental after dark. Unfortunately, junk food can be 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. This is passive eating.

We eat without thinking, not even stopping to enjoy the process. As per ISRN Obesity, passive eating can lead to food addiction because 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 we’d have fewer issues if we replaced junk food with carrot sticks and hummus late in the evening. Unfortunately, the human brain craves sweet and salty junk foods while we relax.

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

Unfortunately, your willpower is likely to be low at this point.

Studies suggest that fast-food consumption rises sharply after 8 PM, while fruit and vegetables are left eaten. The more tired we feel, the likelier we are to cave into temptation.

Night Eating Syndrome

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

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

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

Obesity is a contributing factor to NES. While the condition only impacts 1% of the U.S., there’s a 1 in 10 chance that an obese person also has NES.

Does Sleeping Too Much Cause Weight Gain?

Having established that insufficient sleep leads to weight gain, we should assess if the reverse is true. What happens if we sleep too much?

The main problem that oversleeping poses to BMI is its impact on our metabolic rate. If you spend too much of the morning in bed, you’ll burn significantly fewer calories.

The human body works in defined cycles. This opens the risk of repeating the previous night’s mistake of staying up late and eating more than usual.

How Does Bad Sleep Affect Your Metabolism?

Insufficient sleep, potentially due to eating late and struggling with late-night digestion, will leave you feeling lethargic in the morning. This slows down the metabolism, burning calories more slowly.

This will have further knock-on effects on our food consumption and sleeping habits.

You’re less likely to exercise and burn calories, and your willpower to resist junk food will remain low. You’re likely to eat poorly, consume more calories, and struggle to sleep later that night.

If you feel sluggish, resist the urge to take a nap. If you must get extra rest, restrict your daytime rest to a nap of under 30 minutes. The metabolism is most active at 4–6 PM, so be awake and ready to eat.

Another connection between poor sleep and BMI is hormone production. If you’re sleeping badly at night, four hormones linked to 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 it’s time to stop eating. Leptin also regulates energy and inhibits hunger pangs, so you don’t feel compelled to eat.

When we stay up beyond our natural bedtime, the body ceases to create leptin, so we start passive eating. There’s no instruction to tell us that it’s time to put the bag of potato 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 because we eat without feeling full.

The human metabolism is much slower when we’re tired. Put all of this together, and the reason for weight gain soon becomes apparent.

One hormone encourages you to eat while another neglects to tell you not to, so your metabolism can’t burn calories at the rate you consume them. If you stay up late regularly, you’ll likely gain weight.


Another impact of leptin failing to perform its function is the elevated 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 produces more than it can process. 

Blood sugar levels regulate while we sleep, so healthy sleeping patterns ease concerns about insulin production. Better sleep is among the essential lifestyle changes for people with pre-diabetes symptoms.


Staying up late often triggers a stress response in the brain, releasing cortisol (the stress hormone).

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

A compulsion to eat junk food late at night will add to these fat reserves.

Displeasure with physical appearance and condition and the exhaustion accompanying poor sleep will create more stress. Of course, this results in further weight gain.

does sleeping late and waking up late cause weight gain?

What Is The Best Time To Sleep To Lose Weight?

If you want to achieve weight loss through an improved sleep regime, you need at least 7.5 hours of sleep. If an alarm is set for 7 AM, you should go to bed by 11.30 PM.

If you can retire earlier, that’s even better. Give your stomach 3 hours to recover from eating before going to bed. If you finish eating at 7 PM, begin your bedtime routine at 10 PM.

The good news is that you can train yourself to accept an early night.

Good Sleep Habits And Weight Loss

Getting an early night alone won’t lead to weight loss, so you must modify your diet and other lifestyle factors. Various things can be done to shed the pounds:

  • Brush your teeth after eating because this will suppress your appetite.
  • Exercise during the day before your evening meal so you feel sleepy at night.
  • Drink tap water to stave off hunger pangs, but don’t consume too much liquid close to bedtime because you’ll have to wake up to go to the toilet.
  • Keep calm. The more stressed you become, the more cortisol the 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 alternatives to watching TV to occupy your time in the evening.

Above anything else, maintain a reliable routine, setting an alarm to remind you to go to bed.

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 the pounds, try going to bed earlier.

Here’s some information on the effects of sleeping in a waist trainer.