Why Sleep Loss Makes You Eat MoreIt has long been known that when you skimp on sleep, you're far more likely to overeat, make poor food choices and gain weight. But why? Researchers from the University of Chicago Medical Center have figured it.
The short answer: Too little sleep gives you the munchies.
The long answer: Sleep loss amplifies and extends blood levels of a chemical signal that enhances the joy of eating, particularly the guilty pleasures gained from sweet or salty, high-fat snack foods.
Fourteen sleep-deprived participants in this study, all of whom were young, healthy volunteers, were unable to resist cookies, candy and chips--even though they had consumed a meal that supplied 90 percent of their daily caloric needs two hours before.
The effects of sleep loss on appetite were most powerful in the late afternoon and early evening, times when snacking has been linked to weight gain.
"We found that sleep restriction boosts a signal that may increase the hedonic aspect of food intake, the pleasure and satisfaction gained from eating," said study author Dr. Erin Hanlon. "Sleep restriction seems to augment the endocannabinoid system, the same system targeted by the active ingredient of marijuana, to enhance the desire for food intake."
If you're interested in the science, here goes: This chemical signal is the endocannabinoid 2-arachidonoylglycerol (2-AG). Blood levels of 2-AG are typically low overnight. They slowly rise during the day, peaking in the early afternoon. When the study subjects were sleep-deprived, however, endocannabinoid levels rose higher and remained elevated through the evening, beyond the typical 12:30 p.m. peak. During that period, sleep-restricted study subjects reported higher scores for hunger and a stronger desire to eat. When given access to snacks, they ate nearly twice as much fat as when they had slept for eight hours.
The takeaway: When you get less than five hours of sleep, it will likely result in binge-eating the next day to the tune of an extra 300 calories. If you do this repeatedly, you will gain significant weight.
The study findings were reported in SLEEP.