School programmes encouraging children to take more exercise and eat healthily are unlikely to have any real effect on childhood obesity, a study in the British Medical Journal suggests.

More than 600 primary school pupils in the West Midlands took part in a 12-month anti-obesity programme. But the study found no improvements in the children's diet or activity levels.

Public health officials said they were working with industry to make food healthier.

They also said a sugar reduction programme and the government's sugar tax would help to tackle childhood obesity.

The researchers, from the University of Birmingham, said families, communities and the food industry probably had more of an influence than school initiatives.

They then compared the results with more than 700 children in another 28 primary schools who did not take part.

When the researchers followed up the children 15 months and 30 months after it started, they found no statistically significant reductions in BMI (body mass index)and no improvements in energy expenditure, body fat measurements or activity levels - compared with those not taking part.

Read the full article on childhood obesity by Philippa Roxby at BBC.