People who are tired tend to eat more. For many, this is a major cause of weight gain. But how exactly does that work?
A study has shown that the brains of people who have had less sleep contain higher levels of the natural chemical ghrelin, which increases appetite and cravings for high-calorie foods. Ghrelin is produced by the stomach when it’s empty. In mice, higher ghrelin levels didn’t lead to eating larger portions, but to eating more frequently.
The body is complex, and ghrelin levels aren’t always higher in people with obesity. It may also work the other way around: frequently eating “pleasure foods” can lead to elevated ghrelin levels in the blood. There is a complex interaction between hormones, hunger, and the mind.
Another team of researchers, whose study was published in April 2017, discovered that the brains of sleep-deprived people also respond more strongly to the smell of food. These participants were only allowed 4 hours of sleep for one night, after which they had to smell and evaluate different foods.
Lack of sleep makes you crave food more—and usually less healthy food. A good night’s sleep, a rested body, and a clear mind all contribute to a healthy weight and lifestyle.