A study by the Reading-based Institute of Food Research, which has been funded by Fairfield Catering, shows that most children know which foods are healthy, but are deterred from choosing them by peer pressure.
Pupils are also put off by the often unimaginative presentation of healthy food, and a perception that it offers poor value for money. So Fairfield, which runs catering at more than 300 schools in England, has now launched an overhaul.
Steven Watts, managing director, said: "You used to get your sandwiches wrapped tightly in a bit of cling-film. We've adopted the approach taken on the high street, where they sell things like salad in a box, with a nice label explaining what's in it and a little fork." Mr Watts says sales of the healthier options have "shot up".