A monitoring device that cut TV and computer time in half helped young, overweight children eat less and lose weight, US researchers said. And it worked without creating a lot of conflict between parents and their kids, they said.
"It reduces all of those battles. The parents have to make one decision. After they make the decision, the device does the rest," said Leonard Epstein of the University at Buffalo, the State University of New York, whose study appears in the Archives of Pediatric & Adolescent Medicine.
Many studies have shown that children across the industrialised world are getting heavier, brought on by a sedentary lifestyle, too much fast food, too few fruits and vegetables and TV advertising that encourages children to make unhealthy food choices.
Other studies have found that TV viewing has been linked to obesity. Dr Epstein wanted to see if a device that limited TV viewing could help younger children.
His team studied 70 children aged between four and seven whose body mass index or BMI was at the 75th percentile or higher for their age and gender. A BMI is a ratio of height and weight. All of the children regularly watched TV or played computer games at least 14 hours per week at home.
About half of the children had a TV monitoring device attached to their computers and TV sets that gradually reduced their TV time by 50 per cent.
Researchers used the TV Allowance device made by Mindmaster Inc. in the study, but such machines are also made by other companies.
The children needed to enter an access code to watch TV or play on the computer. When their allowance of screen time was used up, the TV or computer would not work.
Children in the control group had no restrictions on TV or computer use. Their families were given parenting tips on how to reduce their children's TV time.
After two years, children with no time limits had 5.2 hours less screen time per week, while children who had time limits reduced screen time by 17.5 hours per week. BMIs in the restricted group were also lower.
"At the end of the trial, 30 per cent of children (whose screen time was restricted) went from overweight to not being overweight. In the control group, only 18 per cent did," Dr Epstein said.
But there was no difference in the amount of physical activity in either group. Dr Epstein said restricting screen time may reduce mindless eating or eating prompted by TV commercials.
"Our data suggest parents who help children reduce their screen time may be helping them maintain a healthy body weight and prevent the development of obesity in the future," he said.
In a separate study in the same journal, researchers at Stanford University found that after-school sports teams made up of overweight children slowed their weight gain.
The pilot study involved 21 overweight children aged between nine and 11 in one school in a low-income community in California.
Nine of the children participated in an after-school soccer programme for overweight children; the rest got classroom education on diet and exercise.
After six months, all of the football participants saw improvements in their weight, but only five of those who got health education did. The researchers said overweight-only teams may help to overcome children's reluctance to join sports teams and control their weight.