Neuroscientists at the University of California at Berkeley (USA) have shown that spending a sleepless night makes us crave donuts, pizza and other dishes classified as "junk food ." The finding provides a new explanation for the relationship between sleep and obesity.
The researchers used functional magnetic resonance imaging to study the brains of 23 young adults after a normal night's rest and after a sleepless night. In the second case, the frontal lobe, which deals with complex decision-making, showed less activity than usual , while the brain's reward center was hyperactive. This would explain why when participants were offered food, those who had been sleep deprived chose unhealthy snacks and junk food, especially hamburgers, pizzas, and donuts. After an 8-hour night of deep sleep, however, the subjects chose the "healthy" option, consisting of strawberries, apples, and carrots.
" If we don't sleep, the brain structures that control motivation and desire become overactive, " concludes Matthew Walker, co-author of the paper published in Nature Communications . If to this is added that the neurons in charge of evaluating the options and making "adequate" decisions do not work well when we lack rest, the consequence is that those who do not sleep well are unable to make adequate decisions about their diet, they eat excessively caloric foods and they are more predisposed to obesity.
