A sleepless night makes us more likely to reach for doughnuts or pizza than for whole grains and leafy green vegetables. Matthew P. Walker, from the University of California/Berkeley (California, USA), and colleagues used functional magnetic resonance imaging (fMRI) to scan the brains of 23 healthy young adults, first after a normal night’s sleep and next, after a sleepless night. They found impaired activity in the sleep-deprived brain’s frontal lobe, which governs complex decision-making, but increased activity in deeper brain centers that respond to rewards. Moreover, the participants favored unhealthy snack and junk foods when they were sleep deprived. Writing that: “These findings provide an explanatory brain mechanism by which insufficient sleep may lead to the development/maintenance of obesity through diminished activity in higher-order cortical evaluation regions, combined with excess subcortical limbic responsivity,” the study authors submit that lack of sleep: “[results] in the selection of foods most capable of triggering weight-gain.”
