A randomised controlled trial published by The BMJ suggests that school-based programmes aimed at preventing obesity in children are unlikely to have a significant impact on the current childhood obesity epidemic.

Researchers say that wider influences from families, local communities and the food industry may have a greater effect than any school run intervention. 

Around a quater of UK children are overweight when they start school. In the following six years, the proportion of very overweight children doubles (from around 9% to 19%), making this period of time critical for preventative action.

A team of researchers assessed the effectiveness of lifestyle and healthy eating programme West Midlands ActiVe lifestyle and helathy Eating in School children (WAVES) in preventing childhood obesity.

The 12-month school-delivered intervention focusses on healthy eating and physical activity among primary schol children. The programme includes daily additional physical activity opportunities, a helathy eating programme, regular information to parents about local physical activity opportunities and workshops on healthy cooking for families.

However, the researchers found no significant difference in weight, body fat, diet, or physical activity levels at 15 and 30 months in children taking part in the programme compared with those who were not taking part.

The researchers suggested that "nudge" interventions, such as using financial incentives to promote healthy behaviour should be further investigated, but their conclusion so far is that school-based approaches "are unlikely to halt the childhood obesity epidemic".