Conducted by Columbia University’s Institute of Human Nutrition, the study looked at brain activity in well-rested and then sleep-deprived individuals. When shown unhealthy food options, tired participants experienced increased activity in the brain’s reward centers.
A separate study by researchers at the University of California, Berkeley concluded that sleep-deprivation leads to impaired activity in an area in the frontal lobe of the brain. This is the area of the brain that helps control behavior and process complex choices. When experiencing sleep deprivation, this area didn’t respond well – thereby making it easier for tired individuals to choose unhealthy foods.
The results aren’t surprising for two reasons. First, when we’re tired, we let our guard down. We’re not as vigilant in making decisions – and it’s easier to just “go for it.” Second, there’s probably an evolutionary advantage at play. When we’re tired, unhealthy (but calorie-dense) foods like soda and candy can give you a quick burst of energy and momentarily lift fatigue. Back when we lived in caves and fought for our survival, this could have been an evolutionary advantage.
The next time you’re tired and craving something unhealthy, remember this study and know what’s really happening. Grab a handful of unsalted nuts or slice up an apple… and then call it a night. Do your body a real favor and get some rest.