If you're not sleeping enough, you'll probably get a case of the munchies, the same that a marijuana smoker gets, according to research released on Monday.
The new study from University of Chicago and other institutions found that people overeat after a poor night's sleep because food appears far more appealing at this time, with the cannabis-like chemicals of the brain likely producing this effect.
The findings were published in the journal Sleep.
In an interview with NBC News, study author Erin Hanlon said it is quite established how people overeat when they use cannabis, tending to favor yummy and rewarding treats. Their work particularly focused on endocannabinoids 2-arachidonoylglycerol (2-AG), a brain chemical resembling the same ones in cannabis and affects areas like appetite, pain and pleasure.
In the small study involving 14 individuals in their 20s, the team has found that sleep-deprived subjects had higher 2-AG levels for longer periods of time, and led them to snack on unhealthier food items.
"We know that when you activate the cannabinoid system, it modulates brain reward pathways," says Hanlon in the interview. "When you activate the cannabinoid system you are exciting the reward system."
What this means: one will likely find junk food much more irresistible if he or she lacks sleep.
Subjects who were awakened each day at 5:30 in the morning — which slashed their sleep by nearly half — consumed an added 1,000 calories later in the day and chose "highly palatable, rewarding snacks" like chips and sweets. Their 2-AG levels rose higher as well, corresponding to the time they disclosed feeling hungrier.
Those who had adequate sleep also overate but only by an estimated additional 600 calories.
For the researchers, it may be time to take sleeplessness and weight challenges seriously in a nation where two-thirds are obese or overweight and more than one-third are not experiencing enough sleep.
But while sleep restriction inhibits cognitive performance and drives one to overeat, the relationship between poor sleep and overeating is definitely complicated, added Hanlon, whose team now seeks to where and how the endocannabinoids are being overproduced in the brain.
Previous studies have also probed the effects of sleeplessness in the so-called "appetite hormones" ghrelin and leptin, although the relationships also remain unclear.
In a commentary that accompanied the study, Frank Scheer of Boston's Brigham and Women's Hospital said that the results make for "compelling evidence" that food reward mechanisms underlie sleeplessness-related excess food intake and weight gain.
He warned, however, that anti-obesity medications created to target endocannabinoids need to be carefully considered to prevent unwanted side effects.
The drug rimonabant, developed by Sanofi and marketed under brand names Acomplia and Zimulti, was intended to turn off the same brain circuit that leads to the munchies. It was pulled off the market when it was discovered to cause side effects such as depression.
Photo: Juliana Dacoregio | Flickr