A new Northwestern Medicine study has suggested that staying up late every night and sleeping late could put you at risk for gaining weight.
It found that people who go to bed late and sleep late eat more calories in the evening, more fast food, fewer fruits and vegetables and weigh more than people who go to sleep earlier and wake up earlier.
"Late sleepers consumed 248 more calories a day, twice as much fast food and half as many fruits and vegetables as those with earlier sleep times," said the study.
They also drank more full-calorie sodas. The late sleepers consumed the extra calories during dinner and later in the evening when everyone else was asleep.
They also had a higher body mass index, a measure of body weight, than normal sleepers.
"The extra daily calories can mean a significant amount of weight gain – two pounds per month – if they are not balanced by more physical activity," said co-lead author Kelly Glazer Baron.
The findings also have relevance for night-shift workers, who eat at the wrong time of day related to their bodies” circadian rhythms.
The study was published online in the journal Obesity.