The epidemic of child obesity is beginning to get serious attention from governments. In Europe, the number of overweight children is rising by a hefty 400,000 a year, according to data from the International Obesity Task Force (IOTF).
The group also estimates that around half a million European children are currently suffering from health problems often associated with later life because they are overweight or obese.
But in a new review, published in the latest issue of The Cochrane Database of Systematic Reviews, authors found only 22 studies that tested different approaches to childhood obesity, like changes to diet or exercise or both. And not one particular regime was supported by enough evidence to suggest that it prevent obesity in children.
Some of the studies were merely pilot projects that showed great promise but were not designed to be able to measure changes in body weight.
"It is becoming increasingly clear that decision-makers need much more information on which to base policy and programme decisions," said Professor Elizabeth Waters, who is a professor of Public Health based at Deakin University, Melbourne, Australia.
The authors noted that there are many different programmes underway at the moment, which may offer up positive outcomes.
"We believe that programmes aimed at creating environments that enable and support long-term behaviour change are likely to make more of a positive impact than the interventions that people have studied so far," Waters added.
By pooling data, the review drew on findings from about 10,000 participants who were under 18 years old and came from Asia, South America, Europe and North America.
The review made a central contribution to the WHO Expert Consultation on childhood obesity at Kobe, Japan, in June 2005, which will be published next June.
"As one of a number of reviews where a controlled evaluation has been used it makes a valuable contribution to our understanding of childhood obesity. But given the importance of tackling childhood obesity it is clear that there is a need for much more research in the area, and research that is thoroughly designed so that it generates useful data," said another author, Caroline Summerbell from the University of Teeside in England.