According to a two-year study conducted by researchers at the University at Buffalo, limiting television and computer use has a significant impact on helping children lose weight.

Researchers followed 70 children, aged four to seven, who were in the heaviest portion of their age group based on body mass index (BMI). All 70 watched or played video games for at least 14 hours per week.

The children were split into two groups. One group was allowed to continue with their old habits, limited only by their parents. The other had a device connected to their televisions and computers that gradually cut back their viewing time by 50%. The children were able to choose what they wanted to watch or play during the day. However, a username and password was required before they could access their TVs or computers. Once an allotted daily time was spent, the device would no longer work for the remainder of the day.

At the end of two years, researchers found that the children who did not have set time limits spent 5.2 hours less time per week in front of a screen. But those who did have limits reduced their screen time by 17.5 hours per week; also, their BMI was lower.

However, research indicated that decreased TV time did not always lead to more physical activity.

A separate study by researchers at Stanford University found that sports teams designed for overweight children could help them lose weight. Researchers followed 21 nine- and ten-year-olds who were overweight, 14 of whom had never played team sports. Two groups were created: one included nine children who attended a boys-and-girls soccer team that met three times a week; the other attended weekly health classes, which taught the children about exercise and nutrition. After six months, researchers found all nine soccer players reduced their BMI—but only 5 of the 12 who attended the health class managed to do the same.