7 Science Backed Facts About Sleep And Weight Loss You Must Know

Sleep and weight loss are far more interconnected to each other than many may think!


sleep and weight loss: how it works

Let’s say you’re desperately trying to lose weight and are fed up of your laziness. Your game plan may look something like this:

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    Toss out all the junk food from your daily routine
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    Pull out those running shoes gathering dust in the drawer
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    Renew or get a new gym membership, and start using it for good

However, there is a growing amount of scientific evidence which suggests that getting ample sleep in the night should actually also be among the top priorities of anyone serious about weight loss.

Sleep and Weight Loss Connection:

No one can deny that we’ve slowly turned into a nation that is in dire need of a health boost. We stay up till late, wake up before sunrise and have turned into an overweight country. As per a study carried out on the US adults, as many as 30% of them get fewer than 6 hours of sleep most nights.

Although there’s plenty of research data that connects poor sleep to weight gain, in many cases even obesity, some of the new scientific research reveals that the opposite may hold relevance too: implying that getting a good amount of quality sleep at night may help people shed unwanted body weight.

Matthew Walker, Professor of Psychology and Neuroscience, University of California, Berkeley, who is actively involved in studying the connection between sleep and weight loss, stated in an interview to TIME that getting a good night’s sleep is by far the most underestimated factors when it comes to healthy weight maintenance.

It should be kept in mind that as is the case with a majority of weight loss methods, sleep is also not a quick-fix measure. Rather, regularly clocking ample amounts of nocturnal sleeping hours could be that secret sauce everyone yearns for in his/her weight loss efforts!

Hence, if you are someone who is wondering, “Does sleeping help you lose weight?” or “Do you lose weight when you sleep?”, The following facts may put all your doubts to rest.

1. Poor Sleep Can Increase Your Appetite:

poor sleep increases appetite

Many scientific studies, including this one, have revealed that there’s a clear connection between poor sleep and increase in appetite. 

This spike in hunger can happen because of sleep’s impact on a couple of very important hunger hormones – leptin and ghrelin.

Leptin is a hormone that gets released from the fat cells inside the body. It’s responsible for hunger suppression as it sends a signal of satiety to the brain.

Ghrelin, on the other hand, is a hormone released inside the stomach which sends hunger signal to the brain. As expected, this hormone’s levels increase just before the meal time, which is also when your stomach is empty. Furthermore, these levels deplete instantly after you consume a meal.

Anytime you don’t get ample sleep, your body automatically starts producing fewer amounts of leptin and more of ghrelin, thus increasing your appetite and making you feel hungrier.

A study carried out on 1024 volunteers revealed that the ones who didn’t sleep enough experienced 15.5% lower leptin and 14.9% higher ghrelin levels in their bodies, compared to the ones who enjoyed sound sleep at night. The people who slept for shorter durations had higher BMIs too.

If that wasn't enough, the people who don’t get sufficient sleep witness increased concentration of cortisol in their bodies. As you may be aware, cortisol is a stress hormone which is directly related to increase in appetite.

2. Sleep Helps You Burn More Calories:

burn more calories by having a good sleep

A study carried out by Matthew P Walker along with his research team discovered that human body is likely to burn anywhere from 50 to 100 calories per hour during sleep.

As per Walker, whenever you dream during your sleep, your brain is at least as equally active as when you’re awake.

So, if we were to address the question - How much weight do you lose when you sleep? – it’s about how many hours of good quality sleep you can get each night, without going overboard.

Experts have also learned that getting sufficient sleep can encourage healthy metabolism while sleeping for a lesser number of hours can send it for a toss.

For instance, a study published in the year 2012, in Annals of Internal Medicine clearly showed how a group of women and men sleeping for just 4 hours per night experienced higher insulin resistance, thus becoming more prone to diabetes and obesity.

More research in this field has shown that people who stay in cooler temperatures develop a type of fat, referred to as brown fat, responsible for increased calorie burning and also for better insulin sensitivity in the body.

In a study carried out in the year 2014, a group of healthy men were made to sleep in a room with temperature regulated at a steady 66°, for a month. Having continuously slept in that chilly environment, these men experienced 42% increase in brown fat in their bodies and a 10% improvement in their metabolic activity.

Although sleeping inside of cold room may seem like an excellent alternative, please note, you just can’t turn off the AC and then wrap yourself in a blanket! That won’t solve any purpose!

These researchers discovered that it’s the shivering because of the cold that’s one of the important drivers behind this effect. So you must feel cold in the real sense!

No one in the science world suggests that you can successfully lose weight by just sleeping and not making any other behavioral changes. However, considering that majority of weight loss routines are difficult to sustain, what’s the harm in sleeping well enough?

After all, the idea is to improve your metabolic rate, and what you do for it in your sleep may be equally important as whatever you do for it during your waking hours.

3. Lack of Sleep Can Reduce Your Resting Metabolism:

RMR or Resting Metabolic Rate refers to the number of calories burned by our body in its state of complete rest. And this RMR is impacted by various factors including muscle mass, sex, height, weight, and age. Research has revealed that sleep deprivation may directly lead to a lower RMR.

In a study carried out in the year 2011, 14 normal weight men were made to stay awake non-stop for 24 hours. Later on, their RMR was found to be 5% lower compared to the days when they had a normal 8-hour sleep at night.

Their metabolic rate also reduced by 20% (after eating) on the days when they were awake for 24 hours. On the other hand, some scientific studies suggest no major changes in BMR as a direct result of sleep loss. Hence, there’s scope of more research to ascertain the actual impact of sleep loss on BMR.

Nevertheless, other findings in this area suggest that lack of sleep can lead to muscle loss. Muscles burn a greater number of calories during the state of rest, compared to the amounts burnt by fat. Hence, any muscle loss directly impacts and reduces resting metabolic rate too.

In another study, carried out in the year 2010, 10 overweight adults were put on a 14-day diet program wherein they were to moderately restrict their calorie intake. Apart from that, these subjects were allowed either 5.5 hours or 8.5 hours of sleep every night.

Although both these groups witnessed muscle as well as fat loss in their bodies, the ones who slept for no more than 5.5 hours, lost less amount of fat and more of muscle.

As per a study published in the American Journal of Clinical Nutrition, a 10 kg or 22 lbs loss in muscle mass can directly lower the body’s Resting Metabolic Rate by around 100 cals per day.

4. Sleep Helps You Fight Cravings:

Research has revealed that the willpower of people who’re able to order a salad over a burger is partly because of the amount of sleep they had clocked the previous night!

good sleep prevents food cravings

A small yet intriguing study carried out by Matthew P Walker (whom we also mentioned earlier) and his team members in the year 2013, which was also published in Nature Communications, involved 23 non-obese and healthy women and men who were put through two different sleep-related tests.

The first experiment involved them getting full 8-hours nocturnal sleep, while in the second they were asked to stay awake the entire night.

In both the cases, each one of them was placed under a brain scanner the next day and were asked to rate the desirability of certain food items, right from a simple fruit to something more tempting like an ice cream.

When they got a full night’s rest, these people tended to select healthier food items. On the other hand, the same women and men after sleep deprivation experienced increased cravings for not just junk food, but the corresponding areas of their brains (frontal lobe which is responsible for self-control and decision-making, for instance, selection of healthy foods) were greatly inhibited.

On the whole, it was found that the sleep-deprived subjects wanted food items that consisted of an average 600 calories higher than what they opted for after having rested well enough.

In the opinion of Walker, getting a full night of good sleep helps to reboot and refresh the human brain’s circuits, enabling it to make better food choices. Such food choices can be ideal to put one on a path towards better weight control, instead of weight gain.

Please note, it’s not just one single night out that can throw you off your weight loss routine, a 2013 study by the researchers at the University of Colorado revealed that even compromising on a few hours of sleep, continuously for a few nights can lead to weight gain.

Hence, we can infer that lack of sleep hampers the way our brain functions, making it hard for it to make healthy food choices and resist the temptation of high-calorie food items.

5. Sleep Helps Prevent Insulin Resistance:

As you may be aware, insulin is a very important hormone responsible for moving sugar from the bloodstream to the body’s cells, where it can be utilized for energy needs.

As also highlighted earlier, lack of sleep can often lead to body cells becoming more insulin resistant. This has also been successfully verified through many studies, including these two: Study A and Study B.

Any excessive insulin in the body makes one feel hungrier, sending a signal that the body needs to store more amounts of calories as fat. Resistance to insulin is also a precursor to weight gain and type II diabetes.

The Study B we mentioned above involved 11 men who were allowed to sleep no more than 4 hours at night for 6 consecutive days.

Thereafter, it was found that their body’s natural ability to reduce blood sugar levels dropped by as much as 40%. It tells that you need only a few nights of insufficient sleep to make your body cells become insulin-resistant.

6. Sleep Can Enhance Physical Activity:

It has been found that lack of sleep causes daytime fatigue, making a person feel less motivated and less likely to indulge in grueling physical tasks.

A study carried out on 15 normal weight, healthy men, in the year 2009 (published in the American Journal of Clinical Nutrition), found a significant drop in the intensity and amount of their physical activity when they were sleep deprived.

Getting adequate amounts of sleep helps in improving the athletic performance of people. This was proved through another study wherein college-level basketball players were made to spend 10 hours in bed at night, continuously for a time-period of 5 to 7 weeks.

sleep can enhance physical activities

When they did so, they experienced a significant improvement in their speed and reaction times. Furthermore, their fatigue levels also dropped significantly and accuracy got better.

One of the primary reasons why getting ample sleep is closely connected to weight loss is because it helps in making a person feel motivated enough to stick to his/her goals.

Other researches have shown that people who always feel sleepy through the day, tend to exercise less, and often opt for more sedentary activities such as watching television.

7. Sleep Helps You Stick to Your Diet Plan:

In the year 2012, a researcher named Charles Elder at the Kaiser Permanente Center for Health Research carried out a study on 472 obese adults through a weight loss program wherein he held weekly group meetings and counseled them on exercise routines and diet plans.

Elder, along with his colleagues studied many different factors, including the levels of depression, stress and sleep in these people.

Elder stated that during the initial stages of the study, people who were regularly getting 6 to 8 hours of sleep at night fared pretty well when it came to weight loss, compared to those who were sleeping for less than 6 hours or more than 8 hours per night. Stress was another determining factor.

People with low-stress levels and 6 to 8 sleeping hours were almost two times likely to achieve success in their weight loss program, compared to the ones who had higher stress and were sleeping either too little or too much.

Another study in the year 2014, on women aged between 25 and 65, who were officially classified as obese or overweight, also proved these results.

These women took part in a 7-month long weight loss program which revealed that the ones who had fragmented sleep patterns and woke up at least 5 times during the night, lost less amount of weight compared to the ones who enjoyed higher-quality sleep.


The above detailed points are clearly showing that there’s a very solid connection between sleep and weight loss. Anyone who wishes to lose and maintain weight must pay attention to not just exercise and dieting, but adequate amounts of quality sleep too.

As is revealed by many studies, our sleep patterns significantly change the way our body responds to food intake. To begin, if you don’t sleep well enough, you will not be able to resist temptations, your appetite will increase and you’ll never be able to control food portions.

What makes matters worse is that it may become a vicious cycle for you. The less you sleep, the more weight you’ll put on. Then the more amount of weight you put on, the more difficult it’ll become for you to get quality sleep. So go ahead, hit the sack and get some sleep! 

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