Children and teenagers are more likely to concentrate and behave better after eating a healthy school meal, it has been claimed.
Claire Rick, spokeswoman for the School Food Trust, said research has proved that students who eat well at lunch time do better in the afternoon.
"Primary school children are around three times more likely to concentrate and be on-task with their teachers after lunch if they've had a healthier meal in a decent environment and in secondary schools pupils are around 18 per cent more focused," she explained.
"Teachers often talk to us about the impact on pupils' behaviour when they've had a proper lunch rather than filling up on foods full of empty calories. And smaller studies comparing exam results at schools with breakfast clubs to those at schools without found pupils got better results where healthy breakfasts were on offer."
According to Ms Rick, since the introduction of national standards for school food, children are eating more of their five-a-day at school.
She noted that they are being offered lunches that are lower in salt, fat and sugar than average lunches in 2005.
Many students are also entitled to free school meals and this may be the only good meal they get during the day, Ms Rick added.
A recent survey carried out by the School Food Trust revealed that 58 per cent of parents whose children do not have school meals would be willing to try them out of the cost was reduced.
Schools must currently apply to the Department of Education if they wish to use variable pricing.
Under plans in the Education Bill, this requirement would be removed as long as schools do not charge pupils more than the cost of producing the meal.