Parents and fast-food outlets pose the biggest threat to healthy eating in schools, experts have warned.

Much of the focus in the drive to improve the diets of children has focused on educating pupils and teachers about healthy food, but David Craig, lead officer for the Hungry for Success campaign in north Lanarkshire, said parents need more information to ensure confidence in the school meals system.

"There is also the challenge of mobile and static fast-food outlets in the immediate school area," he told delegates at the Children in Scotland agency's Appetite for Life conference in Dunfermline last week.

Hannah Booth, who is overseeing the Department of Health's healthy schools programme in England, agreed.

"The biggest issues are with food brought into the school; food available off site from fast-food outlets; and ensuring that the parents of pupils understand the changes being introduced and support them," she said.

Booth praised the approach to school meals in Scotland. "Scotland is ahead in many ways in delivering healthier food in schools, and we have looked to initiatives such as Hungry for Success in modelling the new English system," she said.

From next month there will be stricter controls over the content of school meals in England, including limiting the number of deep-fried dishes to no more than two a week; introducing oily fish; and requiring a fixed quantity of fruit and vegetables to be served daily.