Unlike in previous interventions, those taking part in the community-based programme were also able to sustain the lifestyle improvements over a 12-month period, research has shown.
The results of the trial are due to be presented in Hungary next week at a European conference on obesity, with the programme's founders claiming it could provide a basis for developing effective national strategies to tackle the health problem.
A total of 107 families with moderately obese children took part in the trial of the Mend programme, which stands for Mind, Exercise, Nutrition and Do-it!
Designed by clinicians from the Great Ormond Street children's hospital and the Institute of Child Health at University College London (UCL), the multi-disciplinary programme teaches both overweight youngsters and their parents about the benefits of healthy eating and exercise in a fun way.
After following the treatment programme, believed to be the largest of its kind in the world, participants reported "statistically significant" improvements to the health of the children, including falls in their body mass index and waist measurements and an increase in their self-esteem.
"Obviously sustaining a healthy lifestyle is the holy grail of health and fitness," commented Mend research director and Great Ormond Street paediatric dietician Paul Sacher.
"The Mend Programme is not a diet but rather helps overweight children and their families build a foundation for healthy living – for life," he explained.
The lottery-funded initiative is now being rolled out across the UK, with organisers hoping it will be in operation at over 300 locations by the end of 2008.
Researchers also want to conduct a larger study of the programme to see if its health benefits can be sustained for a period of longer than a year.
Professor Alan Lucas of the Institute of Child Health said that with 30 per cent of UK children now considered to be obese or overweight, the problem was an "immense public health issue".
"This popular community-based programme has the potential to underpin effective national strategies for obesity treatment and prevention," he stressed.
According to medics, obesity costs Britain some £7 billion a year.
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