Scientists have long associated sleep deprivation with obesity, but whether one causes the other has been unclear.
According to two new studies, sleeping fewer hours than your body needs does in fact impact how you interpret unhealthy food choices.
In one of the studies, 25 men and women of normal weights were placed in an fMRI scanner and then shown photos of nutritious and unhealthy foods. This experiment was conducted after the subjects had either gotten four or up to nine hours of sleep. The other study examined 23 healthy adults after nights of normal and restricted sleep, where the participants rated their food cravings while inside a fMRI scanner.
"The results suggest that, under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods," said Dr. Marie Pierre St. Onge, a research associate at the New York Obesity Research Center and leader of the first study, in an interview with The Telegraph.
Lack of sleep impairs cognitive ability, and makes fast food appear more attractive, since it's a way to obtain a quick burst of energy. On the flip side, there are many benefits to a good night's sleep: It leads to a stronger memory and attention span, curbs inflammation, and reduces stress.