Astute readers may note that when you sleep less, it also increases your calorie expenditure, because your metabolic rate is higher during wakefulness than during sleep. St-Onge and her team have shown that limiting sleep to four hours a night does indeed increase calorie expenditure, but only by about 100 Calories per day. Since her sleep-deprived volunteers ate nearly 300 excess Calories daily, that still leaves 200 Calories to accumulate around their midsections at the end of the day
