Like marijuana, sleep deprivation can trigger food cravings

Up to 75 million adults in Canada and the United States suffer from sleep problems, with nearly 40% unexpectedly dozing off at some point during the day at least once a month. Lack of sleep can disrupt our mental processes and make work, school, driving, and social functioning more difficult. Studies show that sleep deprivation like marijuana can trigger food cravings.

Previous research has shown that inadequate sleep is associated with late-night snacking and junk food cravings. But a study published in the eLife journal examined the neural pathways that link craving symptoms and lack of sleep. When people got just four hours of sleep instead of the recommended eight hours, there was an increase in certain compounds in the body's endocannabinoid system that require high-calorie foods.

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The endocannabinoid system, or ECS, regulates various biological processes such as sleep, appetite, internal temperature and more. All mammals have an ECS, not just humans. These functions are adjusted by endocannabinoids that your body produces naturally and which are similar to the phytocannabinoids in marijuana. When you smoke marijuana, these receptors are activated, causing your body to crave high-calorie foods. According to this study, sleep deprivation works in much the same way.

At the start of the study, researchers asked 25 subjects to get seven to nine hours of sleep every night for a week. The following week, researchers randomly assigned half of the participants to sleep four hours on certain nights, while the other half followed standard sleep schedules. In a cruel experiment, the researchers then had all participants in the study eat from a buffet, with their food choices monitored, including what foods they ate and how much of it.

Photo by Flickr user Jenn Durfey

The study found that sleep deprivation did not necessarily increase the amount of food participants consumed. But it influenced the types of foods they chose, often opting for fattier and higher calorie foods.

“Importantly, the effects of sleep deprivation on dietary behavior persisted into the next day (after a night of unrestricted recovery sleep), with the percentage of calories consumed being higher,” the researchers wrote.

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Throughout the study, scientists also conducted regular fMRI scans to track the brain's olfactory system. Participants were exposed to different smells and their reactions were observed. Those who were sleep-deprived reacted far more strongly to food smells than to any other smells.

“Taken together, our results show that sleep-dependent changes in food choice are associated with changes in an olfactory signaling pathway related to the ECS,” the researchers write. “This pathway is likely not limited to sleep-dependent changes in food intake, but may also influence broader dietary decisions. In this regard, our current findings may help identify new targets for the treatment of obesity.”