To eat right tomorrow, get a good nights sleep tonight. Two studies presented at the annual meeting of the Associated Professional Sleep Societies report that sleep-deprived subjects show brain changes that affect their decision-making and predispose them to poor dietary choices. Both were crossover studies, in which 23 and 25 healthy subjects were tested after being shorted on sleep and after sleeping normally; both used functional magnetic resonance imaging (fMRI) to study brain activity. The first study compared sleeping normally with staying up all night, with snacks at 2:30 a.m. and breakfast at 8:30 a.m. Participants were then quizzed about food desires and given fMRI scans. When subjects were well-rested, the scans showed greater frontal-lobe activity in areas indicative of decision making. The second study compared six days of sleep deprivation with normal sleep. When sleep deprived, subjects responded to fatty, sugary foods with brain activity much like that in studies of the obese.
