6 Ways How a Lack of Sleep Causes Weight Gain and Obesity

1. Disruption of Key Hormones That Regulate Appetite

Research indicates that a lack of sleep causes an imbalance of two hormones in your body. These hormones are called ghrelin and leptin. These hormones are crucial for regulating your appetite. Individuals in a state of sleep deprivation have a decreased concentration of the hormone leptin. This hormone is responsible for signaling the sensation of feeling full. Furthermore, they have elevated levels of the hormone ghrelin in the body. This hormone is responsible for signaling the sensation of hunger. Studies indicate that just a single night of sleep deprivation already causes these hormonal imbalances.

As a result, sleep deprived individuals have a much larger appetite then usual. Additionally, they don’t feel as satisfied by food even after a big meal. This combination often leads to significantly overeating. The imbalance of these two hormones caused by a lack of sleep can increase appetite by as much as 50%.

2. Increased Cravings for Unhealthy High Caloric Foods

Sleep deprived individuals have an increased craving for calorie dense, high carb and high fat foods. Research has established that individuals who regularly sleep less than six hours a night have elevated levels of endocannabinoids. These are chemicals produced by the body which create a very similar effect as does the drug cannabis (the munchies). This chemical stimulates appetite and increases the desire to snack on sweets (cookies, chocolate and ice cream), complex carbohydrates (bread and pasta) and salty snacks (chips and pretzels).

Furthermore, studies indicate that a lack of sleep causes an increase of cortisol in the body. Cortisol is the stress hormone and at normal levels it plays an important role. When you are under stress, cortisol increases your blood pressure and blood glucose levels to provide a quick burst of energy. This is a survival mechanism developed over many millennia of evolution.

Unfortunately, insufficient sleep causes higher levels of cortisol than is healthy. This causes high blood sugar levels as well as a craving for high carb foods as fuel during this ‘stressful’ time. Over time this increases the likelihood of developing obesity and diabetes. To make matters worse, increased cortisol levels hinders your ability to sleep. This creates a vicious cycle.

More information on this topic can be found on the page focused on the Increased Risk of Diabetes as a result of sleep deprivation.

3. Significantly Lowered Metabolism

Studies indicate that the amount of sleep we obtain at night has an impact on our Basal Metabolic Rate (BMR). The BMR determines how many calories our body burns when resting and sleeping. Generally, the BMR is responsible for around 60% of the calories we burn each day. When we are not obtaining enough sleep at night our body automatically goes into ‘energy conservation mode’. As a result, our body slows down the rate of calories we burn to compensate for the increased amount of waking hours. Consequently, we burn 10% less calories compared to when being well rested. This 10% a day builds up over time for as long as the person is sleep deprived and can lead to significant weight gain.

4. Low Energy and Reduced Motivation to Exercise

Regular exercise and activity is crucial for maintaining and/or losing weight. Studies indicate there is a strong connection between sleep and the motivation to exercise. Individuals who sleep less have a drastically reduced motivation to exercise. Studies indicate that the relationship between sleep and exercise is bi-directional. In other words, if you obtain more sleep you will be more motivated to exercise. Additionally, if you exercise consistently, your sleep is going to improve.

Sleep also plays an important role in Non Exercise Activity Thermogenesis or NEAT. This refers to all the common activities you do as part of your daily life such as walking, cleaning, playing with your kids, etc. The daily activities falling under NEAT account for around 15% to 20% of your daily calorie expenditure. For most people NEAT accounts for more calories burned each day than intentional exercise. Therefore it has an important role in weigh management. If you are sleep deprived then you will often feel sluggish and less energetic. Consequently, the amount of incidental movement you do throughout the day as well as the amount of calories you burn is significantly reduced.

5. Lowered Impulse Control Leading to Bad Food Choices and Late Night Binges

Studies indicate that sleep deprived individuals have decreased levels of impulse control. This is because they experience a shift towards a more primitive pattern of brain activity. Consequently, this causes high-calorie foods to become significantly more desirable.

Additionally, many people are the victim of a phenomenon known as decision fatigue. On average we make around 200 food related decisions each day. Our ability to make good food choices drop throughout the day as we are forced to make more and more decisions. As a result, we are more likely to make poor food choices late in the day compared to early in the morning when we feel more refreshed.

Sleep deprivation causes your decision fatigue to be much higher. Consequently, you are more likely to succumb to food temptations. This increases the likelihood of making unhealthy food choices especially late in the evening. Furthermore, the simple fact of being awake for more hours during the day increases the odds that you are going to be hungry late at night when the likelihood of making poor food choices is the greatest. All of these factors contribute to the increased probability of late night binge eating of unhealthy foods.

6. Increased Difficulty to Lose Fat While Sleep Deprived

Studies indicate that the amount of sleep you get at night determines whether your body burns fat or lean tissue for energy. Sleep deprived individuals burn much less fat compared to well rested individuals. This is because when you are not getting enough sleep the body does not want to give up fat. Instead, mostly lean tissue such as muscle mass is depleted while fat is retained. Presumably this is done to conserve energy. Consequently, people who are dieting and trying to lose fat are much less effective if they are sleep deprived.