We all know the importance of getting aĀ good nightās sleepĀ regularly, but according to the CDC, 1/3 of adults donāt get enough sleep. At least seven hours per night is recommended, as chronic sleep deprivation is associated with an increased risk of developing unhealthy conditions like obesity, diabetes, high blood pressure, heart disease and stroke. But itās not just the body that suffers ā too little sleep can also cause mental distress, junk food cravings and poor decision-making. Consider that some of those decisions involve what you eat and drink, and the bodily effects of sleep quality and duration are compounded.
THE LINK BETWEEN SLEEP LOSS AND CRAVINGS
A 2012 Swedish studyĀ published in The Journal of Clinical Endocrinology & Metabolism looked at the connection between sleep and junk food cravings. They noted sleep deprivation is known toĀ stimulate appetite and food intake, so they hypothesized tired humans are more sensitive to the ārewarding food stimuliā of high-calorie foods. After the study period, they found participants who experienced acute sleep loss (those who were not allowed to sleep as much as the others) reported increased hunger and displayed changes in their brains that showed increased activation in response to food images.
The longer the sleep deprivation lasts, the worse things get. The study results suggested prolonged periods of inadequate sleep lead to a greater reward response in anticipation of food. These changes can drive hedonic impulses to consume unhealthier food and to eat larger quantities than necessary.
The researchers note their findings may highlight a potentially important mechanism that is contributing to the growing levels of obesity in Western society. In other words: We donāt sleep enough, and that may be one reason why weāre collectively gaining weight.
AROMAS ARE MORE ENTICING WHEN WE’RE TIRED
A 2019 Northwestern University studyĀ published in the journal eLife looked specifically at why we crave junk food after a night of bad sleep. Like the Swedish study, it noted sleep deprivation impacts food intake and is associated with a preference toward high-calorie options. But it also found our noses are to blame.
According to the researchers, when weāre tired, the olfactory system goes into overdrive to identify food. It also changes how it communicates with the brain, which results in our nose steering our decision-making toward more energy-dense options. This may be why we feel more susceptible to enticing aromas when weāre tired. Just picture the commercials and cartoons showing people rising from bed, as if on a string, as their noses follow the wafting scents of olfactory delights, like bacon and coffee.
In the study, the scientists noted that individuals who slept less were more likely toĀ snack throughout the day, choosing not only more food but higher-calorie foods.
āWe found participants changed their food choices,ā said the studyās senior author, Thorsten Kahnt, an assistant professor of neurology at Northwesternās Feinberg School of Medicine. āAfter being sleep deprived, they ate food with higher energy density (more calories per gram) like doughnuts, chocolate chip cookies and potato chips.ā
THE BOTTOM LINE
So, if you want to curb those junk food cravings, start with a good nightās sleep. Not only will you make better food choices the next day, but keep it up, and youāll feel less susceptible to the charms of sugary, high-fat foods overall. This can help you stave off weight gain, as well as associated conditions like diabetes, high blood pressure and heart disease.
Originally published December 2020, updated May 2022
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