Gender Dependent Effects of TV Consumption on Body Fat Percentage of Canadian Teens

A longitudinal study (57 months) published by the American Journal of Epidemiology on July 8, 2010 found that although there is a negative effect of increased TV-consumption on boys (12–13y), no such correlation exists for the girls:

"Relative to that of steady-low screen-time trajectory group boys, percent body fat was 2.9 (95% confidence interval: 0.7, 5.0) and 2.4 (95% confidence interval: 0.5, 4.2) percentage units higher on average among "increasers" and "steady-high" trajectory group boys, respectively. There was no evidence that screen time has an effect on percent body fat in girls overall, although physical activity modified the association between screen time and percent body fat in both sexes."

Despite these findings, the scientists conclusion,

"Efforts to prevent obesity in youth should emphasize reducing screen time,"

unquestionably holds true, even if it is your daughter who is sitting in front of her TV-screen 24/7 ;-)