Sleeping for ten hours a day helps to reduce the prevalence of obesity in adolescents. Short sleep duration can lead to obesity.

Links between the duration of sleep and BMI had been established by previous studies, but the scientific community had not succeeded in bringing out a unified theory to explain it. Short sleep duration can lead to obesity; one theory suggests that people who sleep less engage in less daytime physical activity due to tiredness. Sleep-deprived people, who are awake most of the time, consume more calories, says another theory. Hormonal changes have also been suggested as an explanation.
Adolescents who fall in the upper half of the BMI distribution are the ones benefitted most from sleep. A higher reduction in BMI was observed with each additional hour of sleep in this group when compared with those in the lower tail of the distribution. The current study is different from most of the previous ones that explored the link; analysis was performed after adjusting time spent in front of computer and television screens, and time spent on physical activities.
Authors fear that educating teens on the benefits of sleep and good sleep hygiene may not have a desired impact on their sleep duration. Instead, they suggest that high schools delay the start of the school day, since this could gift the teens an additional hour or so for extra sleep. Parents can also play key role in helping teens to establish and keep routine bedtimes and wake-up times. Distracters like televisions or computers may be kept away from bedrooms.
Reference: Beyond sleep duration: distinct sleep dimensions are associated with obesity in children and adolescents; Jarrin et al; International Journal of Obesity 2013.
Source-Medindia