We’ve already discussed how sleep impacts every aspect of our lives, from making healthy people hurt, overeating, and making us less tolerant, more frustrated and angry. Now lack of sleep is linked to not only overeating but specifically, overeating junk food. The question is, why?
It’s important to realize that adequate sleep is an integral component in maintaining good health and weight levels.
Part of the answer seems to be that skimping on sleep can disrupt our circadian rhythms. But lack of sleep can also alter hunger and satiety hormones. I’ve reviewed how two hormones help to regulate hunger—ghrelin and leptin. Both have been shown to be affected by sleep. Ghrelin stimulates appetite, while leptin decreases it. When the body is sleep deprived, the level of ghrelin spikes, while the level of leptin falls, leading to an increase in hunger.
Now, a new study finds evidence that sleep deprivation (getting less than five hours of sleep per night) produces higher peaks of a lipid in our bloodstream known as an endocannabinoid, that may make eating more pleasurable.
So, what’s an endocannabinoid? If you look at the word closely, you may already have a clue. The prefix endo means inner, or within. And cannabinoid looks like. . .you got it: cannabis. Our bodies produce compounds that seem to act on the same parts of the brain as marijuana does. We’ve all heard of the marijuana munchies, right? In this new study, based on blood samples, an interesting finding was seen – the daily rhythm of a particular endocannabinoid, known as endocannabinoid 2-arachidonoylglycerol (2-AG). is altered by a lack of sleep. This link is important because the hormone 2-AG controls the desire for food.
These changes “could be the driving force for craving more palatable foods,” according to Erin Hanlon, a Neuroscientist at the University of Chicago Medical Center and the author of this study, published in the journal Sleep. She and her colleagues enrolled 14 healthy 20-somethings who ate the same meal three times a day at 9 a.m., 2 p.m., and 7 p.m. The research team compared the effects of clocking 8.5 hours of sleep over four nights, versus 4.5 hours of sleep over another four nights. The participants also underwent 24 hours of surveillance to monitor hunger, appetite and food intake levels in a sleep laboratory.
After restricted sleep, the young adults had 33 percent greater levels of 2-AG, compared to when they got a normal night’s sleep. The hunger levels also peaked about 90 minutes later, again at 2 p.m. and remained elevated until about 9 p.m.
Sleeplessness also increased the pleasure and satisfaction signals in the body gained by eating food. 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. After the fourth night of restricted sleep, participants were offered a plethora of snack foods. Even after a large meal less than two hours prior to the snack time, they chose sweets and chips that offered 50 percent more calories and twice the amount of fat over healthier options when insufficiently rested.
The large overarching message is sleep restriction and sleep deficiency have been shown to cause multiple harmful outcomes. It’s important to realize that adequate sleep is an integral component in maintaining good health and weight levels. People who believe in the old adage ‘I’ll sleep when I’m dead’ need to revisit their thinking.
Frank Scheer, a chronobiologist at Harvard Medical School, wrote a commentary on the new study that also appears in Sleep. “The hypothesis has always been that food is more appealing when endocannabod levels are higher. But we didn’t know whether those levels would be effected by insufficient sleep, so this is really the first study to nicely show that.”
These findings fit perfectly with brain-imaging studies of sleep-deprived people. They also show increased activity in the brain areas that involve our reward centers when people see images of salty, sugary and fatty snacks.
Not only does a lack of sleep interfere with hunger signals, but there’s also the problem that less time in bed simply gives you more hours of the day to eat. Preventing overeating, and in conjunction, obesity, starts with creating a healthy bedtime routine. To manage your weight and how much food you consume, aim to go to sleep and wake up at the same time every day of the week, and give yourself enough time in bed to get at least 5 hours to counteract the munchies. But, the full benefit comes with 7-9 hours of sleep.
There’s still a lot to learn about all the ways that sleep can influence our appetites and eating behaviors, but these findings serve as a reminder of the importance of getting a good night’s sleep.