Sleep deprivation leads to junk food cravings

A new UC Berkeley study reveals that a sleepless night can make you more likely to reach for junk food instead of a healthy meal.

The findings could help shed light on the link between sleep deprivation and obesity, researchers said.

Brain region responsible for judgment affected

Using functional magnetic resonance imaging (fMRI), the researchers examined the brains of 23 healthy young adults – first after a normal night's sleep and then after a sleepless night. Scans from the sleep-deprived night revealed impaired activity in the brain's frontal lobe – an area that governs complex decision-making processes. Not only that, but results showed an increased activity in the brain centers responsible for pleasure and rewards after a sleepless night.

Participants also outwardly favored more unhealthy foods the day after they were sleep deprived.

"What we have discovered is that high-level brain regions required for complex judgments and decisions become blunted by a lack of sleep, while more primal brain structures that control motivation and desire are amplified," said Matthew Walker, senior author and UC Berkeley professor of psychology and neuroscience, in a press release.

Unraveling the sleep-obesity connection

While previous research has shown that poor sleep leads to a bigger appetite, these results show exactly how the brain becomes impaired when functioning on a lack of sleep.

"This combination of altered brain activity and decision-making may help explain why people who sleep less also tend to be overweight or obese," Walker said.

When presented with things like vegetables, strawberries, apples, carrots, pizza, burgers and doughnuts, the unhealthy foods were chosen more frequently by participants after a night of poor sleep.

"Getting enough sleep is one factor that can help promote weight control by priming the brain mechanisms governing appropriate food choices," Walker said.

Source: University of Berkeley