After having a bad night in which we have had little and bad sleep, we may feel more attracted to unhealthy foods. According to a new study carried out by researchers at the University of Chicago (USA), this happens because lack of sleep increases appetite in a similar way to how marijuana does, since it raises the blood levels of a person. Chemical signal that increases the sensation of pleasure that eating causes us , also enhancing our desire for foods rich in sugar, fat or salt (sweets, chips …)
” Sleep restriction appears to increase the endocannabinoid system , the same system driven by the active ingredient in marijuana, to increase cravings for food,” explains study leader Erin Hanlon.
To shed light on this theory, the experts involved 34 healthy, non-obese young volunteers (14 men and 20 women) aged around 20 years and monitored for two 4-day periods. In the first phase of sleep at the University’s Clinical Research Center, participants could spend up to 8.5 hours in bed and slept an average of 7.5 hours each night. In the second phase of the study, for 4 days they were only able to spend 4.5 hours in bed, and they slept an average of 4.2 hours per night.
In both stays, they all ate the same meals three times a day, measuring their blood levels of ghrelin , a hormone that triggers appetite, and leptin, which is responsible for the feeling of satiety. They also measured levels of endocannabinoids, a type of molecule that is naturally synthesized by the brain and that “turns on” the brain’s reward system .
The researchers identified a normal pattern in endocannabinoid levels on the nights that the participants were able to sleep nearly 8 hours. However, the days of reduced sleep there was a 33% increase in these levels. In addition, the participants reported an increase in hunger, especially after consuming the second serving of the day, that is, the same time that endocannabinoid levels peaked.
Thus, according to experts, lack of sleep increases appetite due to the guidance of the endocannabinoid system, which “ could be a mechanism by which recurrent sleep restriction ends in excessive food intake, especially in the form of snacks , despite of minimal increases in the need for energy, ”Hanlon explains.
The work has been published in the journal Sleep .
