Sleep and Weight Loss – Why isn’t your exercise working?

Does sleep affect weight loss? Studies show that if you’re trying to lose weight, the amount of sleep you get may be just as important as your diet and exercise. Keep watching this video to find out how exactly lack of sleep undoes your exercising efforts.

Written by:


Last Updated: Thu, June 6, 2019

Your workout routine and diet are perfect, and even your heart is in the right place. Still, no matter how hard you work to lose weight, you struggle with the process and can’t get the body you desire.

The worst thing is that someone else who follows the same program GETS the desired results.

When you talk, you find out that both of you share a common approach to weight loss:

Yet, there is a difference between you two. You are the one that continues to struggle. You can’t maintain your focus. You have a hard time controlling your hunger, always crave sweets, and despite your biggest efforts in the gym, you don’t achieve the same results as someone else following the same fitness and dietary plan.

What is the problem? Why isn’t your exercise working?

Maybe you don’t know how to train properly. Maybe you lack the willpower or maybe it’s genetics and there is nothing you can do about it.

There is definitely an answer to your question, and there is definitely a solution for your problem.

Most likely, your problem is lack of sleep.

Studies show that if you’re trying to lose weight, the amount of sleep you get may be just as important as your diet and exercise. Keep watching this video to find out how exactly lack of sleep undoes your exercising efforts.

How Does Sleep Control Your Diet?

Most people who are trying to lose weight believe that a healthy weight loss revolves around eating and movement. Simply put, to look better you need to eat less and move more. However, that’s not so easy to do, and also not the most important thing.

Between living your life, working, and exercising, you’re probably forgetting to sleep enough. Or even worse, you don’t realize that sleep is the key to being rewarded for your diet and fitness efforts. Let’s take a look at some epidemiological research that found the link between sleep and weight gain.

Several studies have been conducted looking at the correlation (degree of association) between body fat and sleep. The results of the research indicate an inverse correlation – less sleep is being associated with more body fat[1], and that is further associated with more fat mass gain over time.[2]

According to the study published in the Annals of Internal Medicine, sleeping less than 7 hours per night can reduce or even undo the benefits of dieting.[3] When our bodies receive less than adequate rest, the amount of fat loss is cut in half. Due to hormonal imbalance, you also become hungrier, feel less satisfied after meals, and lack energy to exercise.

You may be thinking this is correlation research, and therefore it’s not conclusive. However, there is also a persistent relationship between less sleep time and greater fat mass. The link persists even after controlling the possible confounding factors.

For example, in a study published in the Journal Sleep Medicine, researchers have excluded the possible confounding agents, and concluded that the association between lack of sleep and weight gain persists even after controlling demographic, lifestyle, work and health related factors.[4]

We should also mention that researchers have found out that shorter sleep increases expression of genetic risks for high body weight. At the same time, longer sleep duration may suppress genetic influences on body weight.[5]

How Sleep Deprivation Affects Weight Loss

So, how exactly sleep deprivation affects weight loss? Try to remember how you feel when waking up after a bad night of sleep. Do you feel exhausted, dazed, and even confused? Maybe a bit grumpy? If you do, you should know that your brain is not the only one – your metabolism and especially fat cells feel the same way too.

When you are sleep deprived, your body experiences “metabolic grogginess”. The researchers from the University of Chicago came up with this term after observing that due to lack of sleep, the body’s ability to properly use insulin becomes completely disrupted.[6]

Epidemiological research shows a strong correlation between abnormal sleep patterns and metabolic syndrome.[7] Lack of sleep over time leads to insulin resistance, hypertension, diabetes type 2 and obesity.[8]

Reducing sleep for only 2 hours daily can lead to a state of insulin resistance in otherwise healthy persons within a week.[9] Reducing your sleep time for 4 hours affects your metabolism so severe that insulin resistance can be developed only after one single night.[10]

So, why is insulin important for weight loss?

Insulin is a peptide hormone that regulates your body’s ability to process food into energy. Insulin resistance is a very bad thing for weight loss, because when insulin is functioning well, fat cells remove fatty acids and lipids from your blood stream and prevent fat storage. If you are insulin resistant, the lipids will circulate in your blood stream, which leads to producing more insulin. Eventually, the excess insulin will start storing fat instead of using it. This is how you not only become fat, but also increase your chances of getting diabetes.

Apart from insulin, sleep deprivation affects 3 other hormones related to weight gain:

The mentioned hormones are disrupted due to lack of sleep which results in making you feel constantly hungry and therefore hindering your weight loss efforts. Here is how.

Hunger is controlled by two hormones: leptin and ghrelin. Leptin is a hormone that is produced in your fat cells, and which tells your brain when you are full. Ghrelin is known as the hunger hormone and the more you produce it, the more you stimulate hunger while at the same time reducing the amount of calories you burn and increasing the amount of fat you store. To successfully lose weight, you need to control leptin and ghrelin, and as almost every other hormone in your body, these two are also significantly influenced by sleep.

Research shows that lack of sleep increases hunger, and particularly depresses leptin while at the same time increases the amount of ghrelin you produce on a daily basis.[11]

Poor sleep is also linked to changes in serotonin levels – a hormone that significantly influences your appetite. Lack of sleep increases the levels of the stress hormone cortisol, and activates the reward centers in your brain that trigger a need for serotonin. Serotonin is often released by consuming fat and carbs, so this is why you may be constantly craving for sweets and junk food.

So, briefly explained, cortisol makes you want food more, while sleep loss also causes your body to produce more ghrelin. A combination of high ghrelin and cortisol basically shuts down the areas of your brain that leave you feeling satisfied after a meal, meaning you feel hungry all the time—even if you just ate a big and heavy meal.

The hormonal imbalances caused by lack of sleep we just mentioned above, result in an internal battle that makes it almost impossible to lose weight even if you do everything the right way.

How Sleep Loss Sabotages Your Exercising Efforts

As everything we mentioned isn’t enough, sleep loss also sabotages your gym time. No matter whether you want to lose weight or gain muscle, in order to lose fat, you need muscles. Why? Because muscles are the enemy of fat, and they help to burn it.

However, lack of sleep is the enemy of muscle, and studies have shown that sleep deprivation reduces protein synthesis (your body’s ability to make muscles) and causes muscle loss.[12]

Even short term deprivation may completely undo your exercising efforts. According to research, long-term sleep deprivation, may result in higher fat mass gains (due to insulin resistance), while short term sleep deprivation appears to hinder fat loss attempts by reducing the percentage of weight loss that is actually fat mass.

In a study published in the Annals of Internal Medicine in 2010, sleep deprivation adversely affects nutrient partitioning during weight loss. Nutrient partitioning is all about where the energy from the nutrients you take in goes, and whether the calories from those nutrients are burned as fuel, stored as fat, or taken up by muscle tissue to build new muscles. The degree to which each takes place depends on a variety of factors, including genetics and hormonal influences, particularly insulin.

If you are on a weight loss diet, reducing your sleep by 3 hours will result in a rather unfavorable nutrient partitioning effect or simply explained, you will be losing more weight from lean mass than fat mass.[13]

Lack of sleep will also make your body harder to recover from exercise. In order to repair your muscles, your body needs to produce growth hormones and growth hormones are particularly produced in slow wave sleep. Studies show that, in case of sleep deprivation, the body compensates for the lack of GH during the day, and that overall daily exposure to GH is left not significantly different.[14] However, that’s when cortisol comes in to mess things up even more.

Cortisol (which is triggered by sleep deprivation) also slows down the production of growth hormones.[15] So, when you are sleep deprived, the already reduced production of growth hormone is further slowed down by high cortisol levels in your body. When you’re suffering from slept debt, this makes everything you do more challenging, especially your workouts. So, if you’re someone who doesn’t particularly enjoy exercising, this will make it almost unbearable.

Wrapping Up

As you can see, the connection between sleep and weight gain is very hard to ignore, and getting proper night’s rest is equally as sticking to your workout routine and diet.

With our hectic schedules and lifestyles, it may be very hard to get the recommended 8 hours of sleep per night. However, the least you can do is to make sure that one night of bad sleep isn’t followed by a few more. It doesn’t seem like much, but you’re at least off to a good start. Take a look at the resources we found to create this article and let us know your experience in the comments below!


[1] Yi S, Nakagawa T, Yamamoto S, Mizoue T, Takahashi Y, Noda M, Matsushita Y, Short sleep duration in association with CT-scanned abdominal fat areas: the Hitachi Health Study. International Journal of Obesity, 2013. available at “Shorter sleep duration is associated with higher BMI, WC and SFA in men”

[2] Hairston KG, Bryer-Ash M, Norris JM, Haffner S, Bowden DW, Wagenknecht LE, Sleep duration and five-year abdominal fat accumulation in a minority cohort: the IRAS family study. Journal Sleep, 2010. available at “In this minority cohort, extremes of sleep duration are related to increases in BMI, SAT, and VAT in persons younger than 40 years old.”

[3] Insufficient Sleep, Diet, and Obesity. Ann Intern Med. ;153:I–28. doi: 10.7326/0003-4819-153-7-201010050-00002 available at

[4] Di Milia L, Vandelanotte C, Duncan MJ. The association between short sleep and obesity after controlling for demographic, lifestyle, work and health related factors. Sleep Medicine, 2013. available at “After adjustment of several confounding variables, a significant association between short sleep and obesity was obtained, but there was no association between short sleep and being overweight.”

[5] Watson NF, Harden KP, Buchwald D, Vitiello MV, Pack AI, Weigle DS, Goldberg J., Sleep duration and body mass index in twins: a gene-environment interaction. Journal Sleep 2012. available at “Shorter sleep duration is associated with increased BMI and increased genetic influences on BMI, suggesting that shorter sleep duration increases expression of genetic risks for high body weight. At the same time, longer sleep duration may suppress genetic influences on body weight.”

[6] Kristen L. Knutson, PhD,1Karine Spiegel, PhD, Plamen Penev, MD, PhD, and Eve Van Cauter, PhD, The Metabolic Consequences of Sleep Deprivation, Sleep Med. Rev. 2007 available at “…chronic partial sleep loss may increase the risk of obesity and diabetes via multiple pathways, including an adverse effect on parameters of glucose regulation, including insulin resistance, a dysregulation of the neuroendocrine control of appetite leading to excessive food intake and decreased energy expenditure.”

[7] Najafian J, Toghianifar N, Mohammadifard N, Nouri F, Association between sleep duration and metabolic syndrome in a population-based study: Isfahan Healthy Heart Program. Journal of research in medical sciences: the official journal of Isfahan university of Medical sciences, 2011 available at

[8] Knutson KL, Sleep duration and cardiometabolic risk: a review of the epidemiologic evidence. Best practice & research. Clinical endocrinology and metabolism, 2010. available at

[9] Broussard JL, Ehrmann DA, Van Cauter E, Tasali E, Brady MJ, Impaired insulin signaling in human adipocytes after experimental sleep restriction: a randomized, crossover study. Annals of Internal Medicine, 2012 available at “Sleep restriction results in an insulin-resistant state in human adipocytes. Sleep may be an important regulator of energy metabolism in peripheral tissues.”

[10] Robertson MD, Russell-Jones D, Umpleby AM, Dijk DJ, Effects of three weeks of mild sleep restriction implemented in the home environment on multiple metabolic and endocrine markers in healthy young men. Metabolism: Clinical and Experimental, 2013 available at

[11] Benedict C, Brooks SJ, O’Daly OG, Almèn MS, Morell A, Åberg K, Gingnell M, Schultes B, Hallschmid M, Broman JE, Larsson EM, Schiöth HB, Acute sleep deprivation enhances the brain’s response to hedonic food stimuli: an fMRI study. The Journal of Clinical Endocrinoloy and Metabolism, 2012. available at “…acute sleep loss enhances hedonic stimulus processing in the brain underlying the drive to consume food… These findings highlight a potentially important mechanism contributing to the growing levels of obesity in Western society.”

[12] Janne Grønli, Jonathan Soulé, and Clive R. Bramham, Sleep and protein synthesis-dependent synaptic plasticity: impacts of sleep loss and stress, Frontiers in behavioral neuroscience, 2013 available at

[13] Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD, Insufficient sleep undermines dietary efforts to reduce adiposity. Insufficient sleep undermines dietary efforts to reduce adiposity 2010 available at “The amount of human sleep contributes to the maintenance of fat-free body mass at times of decreased energy intake. Lack of sufficient sleep may compromise the efficacy of typical dietary interventions for weight loss and related metabolic risk reduction.”

[14] Spiegel K, Leproult R, Colecchia EF, L’Hermite-Balériaux M, Nie Z, Copinschi G, Van Cauter E., Adaptation of the 24-h growth hormone profile to a state of sleep debt. American Journal of Physiology. Regulative, integrative and comparative physiology, 2000 available at

[15] Madhusmita Misra, Miriam A. Bredella, Patrika Tsai, Nara Mendes, Karen K. Miller and Anne Klibanski, Lower growth hormone and higher cortisol are associated with greater visceral adiposity, intramyocellular lipids, and insulin resistance in overweight girls, American Journal of Physiology, Endocrinology and Metabolism, 2008 available at

Sleep Related

Was this post helpful?

+ posts

A wannabe journalist who somehow ended up as an art historian. She is a gamer, a coffee addict and a sleep aficionado. When she is not researching about sleep and finding out new ways to fight off the insomnia beast, she's spending time with her friends, gaming or visiting local museums.

Leave a Reply

Your email address will not be published. Required fields are marked *