No doubt you already know that weight gain is a matter of calories eaten minus calories burned, but a new study of mice suggests calories add up faster if they’re eaten when you ought to be sleeping. When researchers at Northwestern University fed mice during the day—when they normally sleep—the rodents gained more weight than mice that ate a night, when they’re usually active. In fact, although the two groups ate about equal amounts of food and got the same amount of exercise, the day-fed mice ended up putting on two and a half times as much weight. Other studies hint that the effect holds true for humans, too. Still, if you regularly consume more calories than you burn, math will trump timing—you’re going to gain weight.
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