Don't Blame Web Surfing for Teenage Weight Gain

By Lisa Rapaport

October 02, 2015

NEW YORK (Reuters Health) - Web surfing may not be as big a factor in teenage weight gain as how children's weight at the start of adolescence, a Swiss study suggests.

Researchers followed 621 youths from age 14 to 16 and found the teens who were overweight at the start of the study were 20 times more likely to be overweight two years later than their peers who began at a healthy weight. For those who became overweight, excessive Internet use wasn't linked to the added pounds.

"Internet use could at most reinforce an already existing risk of being overweight," the study team concludes in an article online September 8 in the International Journal of Obesity.

"Nowadays Internet use is almost a necessity to survive in this world, as youths are asked to use this technology," lead author Yara Barrense-Dias of the Institute of Social and Preventive Medicine at Lausanne University Hospital told Reuters Health by email.

"For this reason we must differentiate between screen time devoted to school or work and screen time devoted to leisure," Barrense-Dias added.

To explore how web surfing influences weight gain, Barrense-Dias and colleagues surveyed teens to gather data on their height and weight, how much time they spent online and how much they devoted to exercise, as well as their eating habits, among other things.

At the start of the study, 13.5% of boys and 8.8% of girls were overweight. By the end, 19.4% of boys and 12.4% of girls were overweight, the study found.

Teen boys got more than three days a week of exercise at the start of the study, but less than three days by the end. Girls, meanwhile, started out with slightly less than three days a week of activity and ended with slightly more than two days.

Internet use didn't appear to affect whether the teens gained weight during the study period, though boys were more likely to be overweight than girls.

Limitations of the study include the reliance on teens to report on their own activities, height, and weight, the researchers acknowledge. The study also excluded other screen time such as television or video games.

It's possible the study is too small, and the self-reported results too unreliable, to draw broad conclusions about the connection between teen Internet use and weight gain, Dr. Paul Collings of the Bradford Institute for Health Research in the UK, told Reuters Health by email.

From a biological standpoint, sedentary time can be associated with pediatric obesity because kids who sit around may burn fewer calories, snack more, and sleep less, Dr. Jonathan Mitchell, a pediatrics researcher at the Children's Hospital of Philadelphia, told Reuters Health by email.


Int J Obesity 2015.