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Why insomnia makes you eat

The less sleep you get, the more likely you are to be overweight. Now, The New York Times reports, scientists have discovered one reason why: Sleep loss causes changes in the brain that make you crave high-calorie foods and weakens your willpower to resist them. Researchers at the University of California, Berkeley, scanned the brains of volunteers while they looked at pictures of various foods and selected those they’d like to eat—first, after a night during which they got eight hours of sleep, and then after a night during which they got none.

They found that when sleep-deprived, the volunteers gravitated toward high-calorie options like chocolate and potato chips. Their brains showed increased activity in the amygdala, a region that governs our desire for food, and decreased activity in frontal-lobe regions that regulate decision-making. Not sleeping allows a substance called adenosine to build up in the brain, possibly causing that “double hit” in undesirable brain activity, says study author Matthew P. Walker. Sleeping, he says, is “the single most effective thing people can do every day to reset their brain and body health.”