Sleep deprivation causes changes in metabolism and hormone functioning, which can affect how the body burns and stores fat.
There is also a particular link between sleep loss and obesity, because a lack of sleep lowers leptin, an important hormone that tells the body when it has eaten enough food, and increases ghrelin, the opposite hormone that tells the body to eat more food. The two combined can set the stage for overeating, which in turn may lead to weight gain.
Ghrelin and leptin are both produced in the body. It has been found that thinner people have higher levels of ghrelin production during certain night-time hours, something that is lacking in people who suffer from obesity. People who fail to sleep properly over-stimulate their ghrelin production, which increases the desire for food. Simultaneously, lack of sleep reduces the production of leptin, which is the body’s appetite suppressant. So, if you don’t get enough sleep, the hormones in your body get all out of whack and you think that you’re hungry when you really don’t need the food.
Getting the right amount of sleep can be the first step to making sure that you’re getting the ghrelin and leptin balance that your body needs to naturally maintain a healthy weight. You should also be getting sleep at the right times, i.e. not going to bed excessively late or sleeping only a little one day and then a lot the next day to make up for it. You should endeavour to sleep between six to eight hours each night if you want to naturally balance your ghrelin and leptin levels.
Studies have shown that those who slept less than eight hours a night not only had lower levels of leptin and higher levels of ghrelin, but they also had a higher level of body fat. What’s more, that level of body fat seemed to correlate with their sleep patterns. Specifically, those who slept the fewest hours per night weighed the most.
Food cravings increase as the body seeks an immediate source of energy to compensate for the sleep deprivation.
Deep restorative sleep not only helps keep the satiety hormones at healthy levels but also improves glucose tolerance and insulin sensitivity, lowers cortisol, increases growth hormone and improves thyroid function.
Also, people who are well rested are more likely to engage in physical activity or exercise and have a more positive attitude.
We often turn to food when we are feeling unwell or are tired. Sleep restores and re-builds the body, which leads to an increase in metabolism.
The way you sleep is a habit, and like all habits your sleeping habits can be changed. Bad habits can be hard to break but, with persistence, it is possible to return to an unbroken night of sleep. Your circadian rhythm, which is a 24-hour cycle, helps allow consistent sleep patterns. An increase in the level of the hormone melatonin in the late afternoon and one to two hours before your habitual bed-time enables you to get to sleep.
While some people may seem to function properly without the average eight hours of sleep a night, the same people may find that their body needs to catch up on sleep on weekends, or on trains or planes. Other early signs are micro-sleeps and drowsiness when driving or lack of concentration. These people should be concerned about the long-term consequences of sleep loss on their health.
The combination of an unhealthy lifestyle of bad eating habits, too little exercise and sleep loss leads to a dangerous increase in risk of diseases, including heart disease.
“Among other hormonal effects, we found that sleep restriction caused an increase in ghrelin levels in the blood. Ghrelin is a hormone that has been shown to reduce energy expenditure, stimulate hunger and food intake, promote retention of fat, and increase glucose production in the body. These results highlight the importance of adequate sleep for maintenance of fat-free body mass when dieting to lose weight”. – Dr. Plamen Penev MD Section of Endocrinology at the University of Chicago