TV and video games are often blamed for reducing physical activity among children and contributing to the childhood obesity epidemic. But a new study suggests that more exercise may not be enough to combat the problem.

The authors concluded that regular exercise in the absence of good nutritional practices is not likely to prevent childhood obesity, although they acknowledged that more exercise might have produced a different result.

The study was conducted among children attending 36 day care centers in Glasgow, Scotland. Two hundred thirty-one kids participated in extra 30-minute exercise sessions three times a week. The parents of those children were encouraged to engage them in more physical activity and to limit TV time.

Two hundred fifty children had no extra exercise classes. A comparison at the end of the six-month study period showed that 62 percent of the exercising youngsters were overweight, as opposed to 61 percent of those with no regular exercise sessions. In other words, there was no observable difference between the more active and less active groups.

It's important to address weight issues early, because studies have shown that overweight or obese children are more likely to become overweight or obese teens and adults.

Correcting the problem of childhood obesity requires interventions at every contact point, the authors emphasized -- at home, at school and in the wider environment. Dietary changes might be essential, they noted.