If you’re trying to lose weight, the amount of sleep you get may be just as important as your diet and exercise.
Unfortunately, many people aren’t getting enough sleep. In fact, about 30% of adults are sleeping fewer than six hours most nights, according to a study of US adults.
Interestingly, mounting evidence shows that sleep may be the missing factor for many people who are struggling to lose weight. Here are seven reasons why getting enough sleep may help you lose weight.
Poor sleep has repeatedly been linked to a higher body mass index (BMI) and weight gain.
People’s sleep requirements vary, but, generally speaking, research has observed changes in weight when people get fewer than seven hours of sleep a night.
A major review found that short sleep duration increased the likelihood of obesity by 89% in children and 55% in adults.
Another study followed about 60,000 non-obese nurses for 16 years. At the end of the study, the nurses who slept five or fewer hours per night were 15% more likely to be obese than those who slept at least seven hours a night.
While these studies were all observational, weight gain has also been seen in experimental sleep deprivation studies.
One study allowed 16 adults just five hours of sleep per night for five nights. They gained an average of 1.8 pounds (0.82 kg) over the short course of this study.
Additionally, many sleep disorders, like sleep apnea, are worsened by weight gain.
It’s a vicious cycle that can be hard to escape. Poor sleep can cause weight gain, which can cause sleep quality to decrease even further.
Many studies have found that people who are sleep-deprived report having an increased appetite.
This is likely caused by the impact of sleep on two important hunger hormones, ghrelin and leptin.
Ghrelin is a hormone released in the stomach that signals hunger in the brain. Levels are high before you eat, which is when the stomach is empty, and low after you eat.
Leptin is a hormone released from fat cells. It suppresses hunger and signals fullness in the brain.
When you do not get adequate sleep, the body makes more ghrelin and less leptin, leaving you hungry and increasing your appetite.
A study of over 1,000 people found that those who slept for short durations had 14.9% higher ghrelin levels and 15.5% lower leptin levels than those who got adequate sleep.
The short sleepers also had higher BMIs.
In addition, the hormone cortisol is higher when you do not get adequate sleep. Cortisol is a stress hormone that may also increase appetite.