Sleep Less, Eat More

While sleep needs vary by individual, Mayo Clinic (Minnesota, USA) researchers report that insufficient sleep may cause people to eat more. Andrew D. Calvin and colleagues studied 17 healthy adults, ages 18 to 40 years, who spent eight days and nights in a supervised laboratory. Subjects were free to eat whatever food they wished, but were randomly assigned to either have their normal sleep time cut by one third, or to sleep normally. Among sleep-deprived individuals, continuous brain wave monitoring showed that they spent only 5.2 hours asleep, as compared to 6.5 hours at baseline. The extra time awake did not raise active energy expenditure, but it did raise average caloric intake by 549 kcal per day. Comparatively, the subjects who slept normally reduced their caloric intake by 143 kcal per day while in the laboratory .