Fizzy drinks damage the academic performance of pupils and their sale in schools should be curbed, a panel of experts is to recommend.

Fizzy drinks damage the academic performance of pupils and their sale in schools should be curbed, a panel of experts is to recommend.

The panel appointed by the Scottish Executive to investigate the dietary value of school meals will report next month. It is expected to call for substantial restrictions in the promotion and sale of carbonated drinks in secondary schools.

Concerns have been fuelled by new research in the United States, which found that teenagers who drank large amounts of caffeinated, fizzy drinks were more likely to suffer sleep deprivation and reduced levels of concentration.

The researchers from Ohio State University found that those students who drank fewer fizzy drinks performed much better.

Michael O'Neill, director of education at North Lanarkshire council and chairman of the expert panel, said: "There has to be a real determination to wean pupils off the habit of drinking Coke, Irn Bru and the like." The evidence was now undeniable, he said, adding that a number of education authorities had stopped serving fizzy drinks to pupils at school lunches under guidelines drawn up by the panel in an interim report last year.

Many schools are reluctant to remove drinks machines completely because manufacturers often offer lucrative profit-sharing deals. A large secondary school can make up to £12,000 a year from a single vending machine.

A growing number of schools in Britain and America have introduced bans on junk food and fizzy drinks. At New End Primary School in Hampstead, north London, where sweets, crisps, chocolate, fruit bars, fruit juices and fizzy drinks were banned from lunch boxes last year, teachers have reported a dramatic improvement in pupils' behaviour. Staff at Charles Burrell School in Thetford, Norfolk, claim a water-only policy has helped pupils to concentrate and is improving academic performance.

Gillian Kynoch, Scotland's "food tsar", said: "Parents and teachers have a responsibility to try and control the amount of fizzy drinks being consumed by children. All too often, soft drink adverts target teenagers by giving the impression that all is well in the world if they drink their particular brand of fizzy drink. There is nothing wrong with such drinks as an occasional treat. The trouble is they become a compulsion and teenagers are drinking far more of them than healthier alternatives such as water."

The Ohio research was criticised by the British Soft Drinks Association. A spokesman said the population sample was too limited and did not take account of other factors that might cause sleep deprivation, such as time spent watching television.