Staying Up Late at Night Could Make You Fat

It happens to be common to all teenagers: late night parties, assignment deadlines, Netflix re-runs, they're consumed with all that's happening around them which is probably why their bedroom light is on way into the night. If you're a concerned parent or a teenager yourself, it's time to put a stop to this very unhealthy habit. According a new study published in the journal Sleep, staying up late on weeknights could make a teenager put on a whole lot of weight in about 5 years.

"The results highlight adolescent bed times, not just total sleep time, as a potential target for weight management during the transition to adulthood," said Lauren Asarnow, lead author and doctoral student in University of California-Berkeley.

For the study, researchers analysed data from a nationally representative cohort of more than 3,300 youths and adults. They found that for every hour of sleep they lost, they gained 2.1 points on the body mass index (BMI). This gain occurred roughly over a five-year period.

The results show that many teenagers do not get the recommended nine hours sleep a night and report having trouble staying awake at school. The human circadian rhythm, which regulates physiological and metabolic functions, typically shifts to a later sleep cycle at the onset of puberty. The results suggest that adolescents who go to bed earlier will "set their weight on a healthier course as they emerge into adulthood", Asarnow added.