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When Fridays roll around, I’m so tired and exhausted, all I want is to curl up in bed with Netflix and wait for a delivery man to bring me something terrible and delicious—fried pickles, pizza, macaroni and cheese, any of those will do. In the past three weeks, I averaged around five hours of sleep per night, and I’m not alone. In America, 30% of the population gets less than six hours of nightly sleep. Although I’m lucky enough to not be part of 35.7 percent of the U.S. population that suffers from obesity, at this rate, it won’t take me to join the club. And it’s not just Americans that are losing zzzs and gaining lbs, either. It’s happening in industrialized countries across the globe.
It turns out, there’s a link between sleep deprivation and obesity, and public health agencies are on it. In a study published August 6 in the journal, Nature, researchers at University of California, Berkley, sought to determine how sleep deprivation impacts brain mechanisms governing food selection and desire. They did it by submitting well-rested or sleep-deprived individuals to a food-decision task while scanning their brains in a functional MRI.
The researchers watched their subjects like hawks to ensure that they got either eight hours of rest or twenty-four hours of wakefulness before the test. Then the following morning, they fed them a piece of toast with strawberry jam and put them to work inside the scanner. Their task was to rate a photograph of food on a scale of one to four to show how much they wanted the food “right now.” Foods ranged in caloric value and fit into the categories of salty, sweet, fruit, dairy and starchy. As subjects rated photos of chips and apples, researchers kept a keen eye on the activity in a few parts of the brain they had predetermined would play a role in food choice.
Because one hallmark of sleep loss is abnormal function in the frontal cortex, researchers picked out three cortical areas including the anterior insular cortex, lateral orbital frontal cortex and anterior cingulated cortex. These areas are involved in signaling and integrating food features like taste and smell and values that lead to appetitive choices. They also looked at a subcortical area, the amygdala, because it is especially responsive to food stimuli. It’s also involved in processing threats. They found sleep-deprived subjects exhibited decreased activity in all three cortical areas and increased activity in the amygdala. In addition, the sleep-deprived subjects tended to want more high-calorie foods (by about 600 calories) than rested subjects. And the sleepier they were, the higher the calories.
What might be going on is that with sleep loss we are heightened to food stimuli and unable to value them properly. Our body is worried about why we’re not taking time to rest. Is there something threatening out there? Quick, load up on calories. We may need them to fight. Survive. Bring on the fried pickles. - by JoAnna Klein
