How Poor Sleep Can Lead to Weight Gain

Date Published: 28 Aug 2018 Categories: News
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Are you trying to lose weight by eating more healthy and exercising more? Great! But chances are you are ignoring another important aspect of weight loss: sleep!


Poor sleep can lead to weight gain

A lot of research has been done towards the relationship between poor sleep and weight gain. For example, one study has shown that adults who sleep less than 5 hours per night have a 55% higher risk of being obese. Another study has shown that obese adults generally sleep 1.5 hours less than lean adults, and lean men who sleep less than 5 hours each night have a 91% higher chance of becoming overweight than those who slept more than 5 hours. These studies are just the tip of the iceberg, and present a clear message: sleep cannot be ignored in the fight against weight gain. Let’s take a look at why sleep is so important for losing weight.


Five reasons how poor sleep can lead to weight gain.

Sleep is the foundation of a healthy individual: it is important for our immune system to work well, for our brain and cognitive performance to stay optimal, and for our body to recover from injury and illness. Here are five reasons how poor sleep can lead to weight gain.


  1. Poor sleep can make you feel more hungry

Two hormones that are important in gaining or losing weight are leptin and ghrelin. Leptin decreases appetite, while ghrelin increases appetite. These hormones are important for maintaining a healthy energy intake. However, even after just one night of poor sleep, the leptin levels decrease, and the levels of ghrelin significantly increase, which causes an increased feeling of hunger. Being hungry in a world where food is available on every streetcorner is not going to help a person stay lean or lose weight.


  1. Poor sleep affects our decision making

Because poor sleep affects our decision making abilities, and our judgement, we may be more likely to opt for an unhealthy snack as opposed to something more healthy when we get hungry.


  1. Poor sleep reduces your metabolism

Melatonin and Thyroid-Stimulating Hormone, or TSH for short, are two other hormones that play an important role in weight gain. Melatonin is also called the “dark hormone” as its production is suppressed by light.  Short-sleeping individuals may be exposed to more light at night, and thus their melatonin levels are suppressed. As a consequence, the reduction in insulin secretion leads to elevated blood glucose, which may result in weight gain, insulin resistance and diabetes. TSH stimulates the production of two other hormones; T3 and T4, which help your body with energy metabolism. However, poor sleep decreases the production of TSH, which leads to the reduction in T3 and T4 hormones, and eventually to the reduction in metabolism. Thus, as a result of poor sleep, your metabolism, or energy expenditure, will decrease.


  1. Poor sleep decreases physical activity

Studies have also shown that after just one night of poor sleep, a person is more likely to be physically inactive, decreasing the energy expenditure even further.


  1. Poor sleep reduces fat burning

Poor sleep also results in our body burning more carbohydrates and less fat for energy, which may also lead to weight gain, insulin resistance and diabetes.


The relationship between poor sleep and obesity goes two ways: we have already mentioned how poor sleep can lead to weight gain and obesity, but weight gain or obesity can also lead to poor sleep. For example, people with excessive body weight are more likely to experience depression and stress, which are both known to influence sleep and cause insomnia. But lifestyle factors that are often associated with living with excessive body weight such as poor eating habits and lack of physical activity also have a negative effect on sleep.


If you are trying to lose weight, it is important to make sure you are getting between 7 and 9 hours of sleep each night, and that your sleep is of good quality. Visit for more information on how you can improve your sleep.


By SSISA Sleep Scientist Rob Henst

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