Everyone knows children are getting fatter and that both a poor diet and a lack of exercise are to blame. But, what researchers have been unable to discover until now, is exactly how major a role activity plays in the battle to keep obesity at bay.

Now a new report published in the journal PLoS Medicine, offers new hope for parents concerned about the growing obesity epidemic. It suggests that making even small increases to your daily exercise routine, such as walking your child to school each day instead of taking the car, could have dramatic long-term results.

Using the latest cutting-edge techniques, researchers discovered that doing 15 minutes a day of moderate exercise lowered a child's chances of being obese by almost 50 per cent. As long as the activity was at least of the level of a brisk walk - enough to make your child a little out a breath -- it seemed to be of benefit.