The Connection Between Sleep and Appetite

Our sleep duration affects the level of our body’s energy and release of hormones. Lack of sleep increases our appetite while reducing the level of satiety at the same time,

Have you ever wondered why do we feel such an urge to snack or eat junk food late at night? Could it be that there is an actual cause and excuse for our late night food cravings? You can be relieved, because science says yes, so keep reading to find all about it.

The amount of sleep that we have affects the level of our body’s energy and release of hormones, and when we do not get enough sleep, our appetite increases as a consequence. Sleep deprivation and obesity are two major health-related problems that affect millions of Americans, so it is not a surprise that they often go hand in hand. Our hectic lifestyles leave little or no space for regular sleeping habits but also for a healthy and balanced meal schedule, which is the reason why many choose to skip their breakfast or overeat during the late evening hours. One problem triggers another, and bad sleeping habits lead to irregular and unhealthy meals, which results in gaining weight.

Sleep deprivation begins as soon as you get less than 7 hours of sleep, that triggers many different problems with the way our body functions, and even just one hour less of rest can cause problems with our immune system, hormone release, etc. Lack of sleep increases our appetite while it is reducing the level of satiety at the same time, which cause us to crave particularly sugary food and carbs. If this condition lasts, and we continuously overeat, that increases our body weight and blood sugar level. The good news is that, if you are not chronically sleep-deprived, and it lasts only a few days, you can quickly reverse the adverse effects of it by simply giving yourself a few nights of proper 8 hours of sleep. Although it is comforting to know that, don’t rely on it too much and try avoiding unhealthy sleep patterns because it will be better for your health in the long run.


Loss of Sleep and Appetite

From a scientific point of view, it is all about hormones, they are in charge of our food cravings, and they suggest when we are full or hungry. Leptin is a hormone with a primary role to maintain the body’s weight, and it is released by the fat cells, so people who have more body fat will also have an increased level of leptin. With lower weight and body fat percentage, the level of leptin decreases. Leptin is the hormone in charge of signaling fullness to the brain, but when, for example, someone loses weight, and the level of leptin falls, that can trigger a sudden increase of appetite and food cravings, which hinders weight loss process.

When the body is functioning normally, excess fat cells produce leptin which is a signal to the hypothalamus to lower down the appetite, but the problem occurs with obese people who have above the average presence of leptin in their blood, because they are more prone to develop leptin resistance or lack of response to the hormone. Having a naturally low level of leptin is rare, but it happens, and this is called congenital leptin deficiency, which basically means that something is preventing our body from producing leptin. Low production of leptin, tricks our body into thinking that it has no fat, which results in with a strong feeling of hunger or cravings. This condition is usually common among kids and teenagers, and it is treated with leptin injections.

The second hormone essential for our appetite is called ghrelin. The ghrelin hormone is vital for appetite and the release of growth hormone, it is mostly produced in the stomach and small intestine, but some smaller amounts of it are also released in our brain and pancreas. It has many roles, and one of them is appetite control which is the reason why ghrelin became known as the “hunger hormone.” Ghrelin has an impact on the hypothalamus, which is the part of the brain in charge of appetite control, but it can also have an effect on some other parts of the brain which control reward processing. Besides that, it helps with the control of the release of insulin, and it has an overall protective role of the cardiovascular system.

When we are missing sleep, our body drops down its level of leptin, while at the same time level of ghrelin increases, which signals the feeling of hunger. For example, it has been shown that people who suffer from chronic insomnia, have a below average level of ghrelin, around 30% lower than the people who get enough sleep, while their level of leptin stays in the boundaries of the normal during the night. That suggests that insomnia promotes weight loss, not weight gain, but that does not mean that people who suffer from insomnia are safe from weight gain, because, during the day, their level of ghrelin suddenly increases for more than average, which stimulates the appetite. This dysregulation of the balance might be the cause of why so many insomnia sufferers gain weight over time.

Besides changes in the levels of ghrelin and leptin, sleep loss also impacts orexin levels in the brain. Orexin is a neuropeptide, also known as hypocretin, and it is in charge of regulation of wakefulness, arousal, and appetite, so it is pretty clear why it is so important for this topic. Neurons that produce orexin are located in the hypothalamus and perifornical area, and there is usually between 10.000 and 20.000 of them, which is not much, but since orexin was “recently” discovered in 1998. a lot of things about the way it works are still unclear and remain a mystery.

When we are tired and sleep-deprived, there are not many things that we are willing to do, but eating is not one of those things that we are ready to neglect so easy. Somehow at that state, we manage to find the energy and enthusiasm to eat, and that can be connected to the orexin because its system is more active when we are sleep-deprived. Usually, people who suffer from narcolepsy have a decrease of orexin, and a study performed on narcoleptic dogs showed that when they get exposed to food, they often experience a sudden cataplectic attack, which suggests us that something has been triggered in their orexin circuit.

When it comes to sexes, surprisingly there are some differences between men and women. After periods of poor sleep, men responded with a higher level of ghrelin than women did.


Can Lack of Sleep Cause Diabetes?

When it comes to serious health problems such as diabetes, we are aware that our family medical history and what we eat are mainly responsible for it, but the loss of sleep has also been connected to it as a possible cause. Sleep deprivation is often overlooked, but it is, in fact, a significant risk factor for type 2 diabetes.

Type 2 diabetes is the most common type of diabetes, and it usually signals that our body is not using insulin correctly, that it has insulin resistance. It is treated with changes in lifestyle, pills, and insulin. Insulin is a hormone produced in our pancreas, and it allows our body to use sugar from the food, while also regulating the level of our blood sugar. Our body cells need sugar for energy, but sugar cannot go directly into most of the cells – insulin is that key hormone that signals to the cells when they need and can absorb sugar. When our body is not producing enough insulin, or there is a state of insulin resistance, that leads to higher level of blood sugar, and many more other complications.

When our body is producing less insulin due to sleep loss, it also produces less stress hormones, for example, cortisol, which keeps us awake while hindering the way insulin should do its job. As a consequence of that, too much sugar (glucose) remains in our bloodstream, which increases the risk of developing type 2 diabetes. It has been proven that this is a possible outcome for people who sleep between 4 and 6 hours each night because they are not getting enough of that deep, restorative sleep which plays an important role in the maintenance of optimal insulin sensitivity and control of the blood sugar.

Lack of sleep messes our hormone levels, and it increases the level of cytokines in our bloodstream, which can sometimes result in insulin resistance. Another cause of it can be the increased release of growth hormone. While people who sleep regularly experience the release of growth hormone during their shut-eye time, researchers have found out that for people who are skipping on sleep that works a bit differently. The release of growth hormone from the brain is somehow split into two portions in people who are chronically losing their sleep. That means that instead of one portion of growth hormone per night, they get two, one before they fall asleep, and the other one after. Higher exposure to growth hormone throughout the body can lead to an increase in insulin resistance.


Tips for Developing Better Sleeping Habits

Since now you have read how serious the consequences of sleep loss on your health can be, it is time to turn to those positive things that you can do to prevent that and improve your health and lifestyle.

  • Exercise – regular exercise improves our health, and it will help all those sleep-deprived night owls to get more tired and hopefully fall asleep earlier and on time. Just try avoiding exercising right before the desirable bedtime, it is optimal to exercise at least four hours before because a higher level of endorphin and body temperature can keep us awake.
  • Natural light – exposing yourself to more natural light will help your body improve its circadian rhythm, and it will be easier for the body to recognize when the night begins to fall.
  • Scheduled meals – eating healthy and regularly is also essential. Moderated and timed portions of food should be practiced each day, at approximately the same time, which will help our body to develop patterns and release hormones at the same time. Avoid eating before bed, high-fat junk food and sugary food especially, because not only that it is not good or healthy, but those digestive processes can interfere with your sleep.
  • Bedtime routine – by now we should all probably know the benefits of a healthy sleep routine, consistent sleep schedule will train our brain to release the sleep hormones at the same time each day. Try sticking up to this routine even during the weekends, and your body will be grateful.
  • Stress – this is a major cause of insomnia and sleep deprivation among people, and although it seems hard, it is important to find a way of going to bed relaxed and free of worries. Yoga and meditation can reduce stress and also help with insomnia symptoms, but if that’s not your thing, try finding something that will relax you before falling asleep.


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