A new study could explain the three bags of chips you just consumed in the last 10 minutes, even though you just ate lunch two hours ago. Chances are, you're a sleep-deprived mom and you've got the munchies! (Yes, like the pot-smoking munchies.)
According to researchers from the University of Chicago, the lack of sleep produces brain chemicals similar to those found in cannabis (called endocannabinoid 2-arachidonoylglycerol or 2-AG), which makes food more appealing and can lead to overeating.
The researchers wanted to know how sleep loss connected to weigh gain so they closely monitored 14 healthy volunteers in their 20s in the university's sleep center. The volunteers spent four days with either 8.5 hours in bed each night (average of 7.5 hours of sleep) or 4.5 hours in bed each night (average of 4.2 hours of sleep).
They ate identical meals at 9 a.m., 2 p.m. and 7 p.m. every day. After four nights, no one got to eat anything until 3 p.m. but could eat as much of their favorite foods as they wanted after. While everyone overate and consumed about 2,000 calories (about a day's worth) at once, those sleep-deprived ate another 1,000 calories a few hours later in the day (vs. another 600 calories for participants with normal sleep) and chose foods with twice the amount of fat and snacks that tasted good and were rewarding (think junk food).
"We know that when you activate the cannabinoid system, it modulates brain reward pathways," lead researcher Eric Hanlon told NBC News. "When you activate the cannabinoid system, you are exciting the reward system."
When the researchers took blood samples, they noticed that for normal sleepers, 2-AG levels in the blood were low overnight and rose slowly, peaking in the afternoon. For sleep-deprived participants, 2-AG levels rose higher by about 33 percent, peaked later and remained elevated until around 9 p.m.
"At the same time, where we see people having this lack of ability to inhibit snack intake corresponds to the time that we see an increase in concentrations of circulating endocannabinoids," Hanlon said.
The statistics are hard to ignore. Every 2 in 3 adults surveyed as overweight or obese in the U.S., and more than a third of Americans are not getting enough sleep. Both obesity and lack of sleep can increase chances of serious health problems like heart disease.
For parents, especially, the lack of sleep is seen as a typical and inevitable part of parenthood instead of a public health issue; only recently has the government offered "practical help and support" for sleep-deprived moms and dads.
"I feel that parental sleep deprivation in the 21st century is more of a systemic problem," writes mom.me contributor Tracy Brennan. "When more and more both parents are—whether by choice or necessity—working full-time, there needs to be more resources out there. It shouldn't seem taboo to seek help."