Why Sleep Is Important for Weight Loss?

The recommended sleep time for adults is seven to nine hours every night; however, many people sleep less than that. Studies have shown that sleeping less than the recommended amount of time is associated with increased body fat and an increased risk of obesity. It may also affect how easily weight can be lost when following a limited-calorie diet.

Usually, the goal of weight loss is to reduce the amount of fat in the body while retaining the most muscle mass possible. Not having enough sleep may limit the amount of fat that can be lost as well as the retained muscle mass while following a limited-calorie diet.

One study has shown that sleeping for five and a half hours every night for two weeks while following a limited-calorie diet led to losing less fat when compared to sleeping for eight and a half hours every night; however, it also led to losing a bigger amount of fat-free mass (including muscles).

Other studies have shown similar results over a period of eight weeks when the amount of sleep was reduced to one hour per night for five nights a week. These results have shown that even trying to catch up on sleep during the weekend may not be enough to reverse the negative effects of sleep deprivation while following a limited-calorie diet.

Metabolism, appetite, and sleep

There are a lot of reasons behind the association between excessive lack of sleep and weight loss. It includes changes in metabolism, appetite, and food choices.

Sleep affects two of the most important hormones that control appetite, which are leptin and ghrelin. Leptin is the hormone that reduces appetite, which is why, when its levels are high, we often feel more full. On the other hand, ghrelin is the hormone that stimulates appetite, and it is often called the “hunger hormone” because it is believed that it is responsible for feeling hungry.

A study has found that limiting sleep increases ghrelin and reduces leptin. Another study, which included a sample of 1024 adults, found that reduced sleep is associated with higher levels of ghrelin and lower levels of leptin. This combination can lead to increased appetite, which can make sticking to a limited amount of calories harder and make a person more prone to overeating.

Furthermore, overeating due to hormone changes can lead to weight gain, which means that sleep deprivation in the long run may lead to weight gain because of these changes in appetite.

Therefore, getting a good night’s sleep must be a priority. Along with the changes in appetite hormones, it has been shown that a lack of sleep affects food choices and the way the brain views food.

Researchers have found that the brain regions that are responsible for rewards are more active when responding to food after losing sleep (six hours only every night for six nights) when compared to people who slept well (nine hours every night for six nights).

This can explain why sleep-deprived people eat snacks most of the time and tend to choose carbohydrate-rich foods and sweet-flavored snacks when compared to those who get enough sleep.

Sleep duration also affects metabolism, specifically glucose (sugar). When you eat, our bodies produce insulin, which is a hormone that helps to process glucose in our blood; however, losing sleep could weaken our body’s response to insulin, which makes it less able to absorb glucose.

Sometimes, we may be able to make up for a night of sleep loss; however, in the long run, this may lead to health conditions such as obesity and type 2 diabetes.

Research has shown that one night of limited sleep (four hours only) is enough to weaken the insulin response to glucose intake in healthy young adults.  Considering that sleep-deprived people tend to choose foods that are rich in glucose due to increased appetite, the weakened ability to process glucose can make matters worse.

Extra glucose (whether it is from excessive intake or a reduced ability to absorb it) can be turned into fatty acids and stored as fats. Altogether, this can accumulate over the long term, which leads to weight gain.

Even so, physical activity is promising as a countermeasure against the negative effects of lack of sleep. Exercise has a positive effect on appetite by reducing ghrelin levels and increasing levels of peptide YY, which is a hormone produced by the intestines, and it is associated with feelings of sufficiency and satiety.

After exercising, people tend to eat fewer amounts of food, especially when energy consumption is taken into consideration. Research has also shown that exercise may protect against impaired metabolism caused by lack of sleep by improving the body’s response to insulin, which leads to improved control over glucose.

Moreover, research has shown the potential benefits of just one exercise session on glucose metabolism after sleep limitation. While this seems promising, studies haven’t determined the long-term effects of exercise on people who struggle with lack of sleep.

It is clear that sleep is important for weight loss because a lack of sleep could increase appetite due to hormonal changes. It can also affect how we lose body fat while counting our calories; therefore, sleep should be considered essential along with diet and physical activity as part of a healthy lifestyle.