A new study has found that cutting the amount of time kids use the TV or the computer in half had two positive effects: the kids ate a lot less and they lost significant amounts of weight.

This is very welcome news, especially in the U.S., with its explosion of childhood obesity. Today, an estimated 16 percent of children between 6 and 19 are overweight — 45 percent higher than a decade ago.

"Television viewing is related to consumption of fast food and foods and beverages that are advertised on television," the study authors said. "Viewing cartoons with embedded food commercials can increase choice of the advertised item in preschoolers, and television commercials may prompt eating."

In the study, Leonard H. Epstein, professor at the SUNY Buffalo, and colleagues studied 70 overweight children, aged 4 to 7, who watched TV or played computer games for 14 or more hours a week. Researchers installed a monitoring device on each television and computer the child used; they then reduced the children's weekly screen time by 10 percent a week until a 50 percent reduction had been reached. In addition, the kids received incentives including money and stickers to entice them away from the TV or computer screen.

A control group of overweight children had no limits put on their use of TVs or computers.

Epstein's team found that, during the study, the children who had no restrictions on their computer or TV use reduced their TV watching or computer-games playing by 5.2 hours a week. But the kids with restricted use cut their TV and computer time by 17.5 hours a week. The children who watched less TV and spent less time on the computer lost more weight than the other children. Interestingly, there was no difference between the two groups in type or amount of physical activity.

Dr. David Katz, director of the Yale University School of Medicine Prevention Research Center, said the study, "shows the upside to this ominous mix — reducing screen time can help prevent childhood obesity by several mechanisms. Less screen time may be even more important to dietary pattern than to physical activity pattern. But by either means, the ends here are encouraging and highlight the importance of this strategy."

This study is published in the March issue of the Archives of Pediatrics & Adolescent Medicine.