Study: Less TV and computer use lowers BMI in young children

May 1, 2008

Child BMI could decrease thanks to less TV time and computer use.

Though watching less television has been shown to slow increases in body mass index (BMI) in school-aged children, the effects of such reductions on younger children have not been thoroughly studied. A recent study in children 4 to 7 years old fills that gap. Using newspaper advertisements and direct mailings, investigators recruited 70 children with BMIs at or above the 75th percentile for age and sex, and divided them into intervention and control groups.

Youngsters in the intervention group reduced television viewing and computer use by 10% per month until they spent half as much time at these activities as they did at baseline. Time spent with the TV or computer was kept to no more than this amount for the rest of the two-year study period by installing a TV Allowance in each intervention family's home. The TV Allowance is an automated device that controls and monitors the use of televisions or computer monitors, making it impossible to turn on the computer or TV once the weekly TV/computer budget was reached. Children in the intervention group also earned 25 cents for each half hour under budget they spent in television/computer use, up to $2 a week.

Children in the control group had unlimited access to television and computers, and received $2 a week for participating in the study. Investigators provided both groups with monthly newsletters designed to motivate participants to reduce viewing, be more active, and eat less. Investigators also monitored participants' BMI, caloric intake, and physical activity every six months.

Commentary:

It seems that the weight loss seen here was caused primarily by decreased caloric intake rather than increased physical activity-an illustration of the link among TV viewing, food advertisements, and eating.