COURTESY THE NEW YORK TIMES
Evidence has suggested for some time that sleep deprivation can lead to obesity, among a host of other ills. Now researchers are digging into the mechanisms that cause our sleep-deprived brains to crave food they do not need.
A study published on Tuesday in the journal SLEEP suggested that the brain receptors that can lead the sleep-deprived to crave unnecessary food were the same as those activated by marijuana. Essentially, not sleeping can give you a ferocious case of the munchies.
The study took a close look at receptors affected by endocannabinoids — so named for cannabis, the marijuana plant — which it found were closely involved in the food cravings that come from sleep deprivation. Sleep restriction in the study’s subjects led to amplified endocannabinoid levels in the blood, leading to hunger pangs, which generally intensify in the early afternoon, to increase further.
Fourteen healthy, non-obese subjects between the ages of 18 and 30 participated in the study. All of the subjects participated in both aspects of the study, undergoing four nights of either healthy sleep or sleep deprivation, after which they were given two regular meals as well as unlimited access to “palatable snacks,” including candy, chips with guacamole and salsa, Doritos, Cheetos and ice cream, as well as healthier options such as fruit and yogurt.
Subjects who were deprived of sleep said that they felt hungrier, and had more trouble controlling themselves when faced with the snacks. They ended up consuming nearly twice as much fat and protein as the control group. (There was not a significant difference between the calories consumed by each group during regular meals.) Previous studies have shown that the sleep-deprived are particularly vulnerable to foods that are high in fat and carbohydrates.
Identifying the system involved in uncontrollable food cravings may help scientists develop new areas of research that could help people harness unnecessary eating, the study said.
“Just knowing what systems are in play to cause increased hunger and appetite in sleep restriction presents a novel avenue” for helping people control those cravings, the lead author of the study, Dr. Erin Hanlon, said in an interview.
She agreed that a less-than-novel solution — getting more sleep — would also help.
The endocannabinoid system is involved in various brain functions, including stress management, immune response and pain modulation. It has even been linked to the “runner’s high” that many feel after aerobic exercise. But the new study represents the first time that scientists have found the system to be affected by sleep deprivation, Dr. Hanlon said.
Research suggests that losing sleep slightly increases the body’s need for calories, but that people who are sleep deprived often consume far more than they need.
The study comes as Americans are voluntarily curtailing their own sleep, a practice that may correspond to a sharp rise in obesity rates over the last several decades.
Between 2005 and 2007, nearly 30 percent of adults said that they slept six hours or less per day, according to data from the National Health Interview Survey. That’s an hour less than the minimum amount of sleep recommended for adults.