School Fund Trust: Healthy eating improves school performance
Ms Rick said that primary school children are particularly likely to respond well to eating healthily.
She said: "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."
In comparison, pupils at secondary school will be about 18 per cent more tuned into their classes after eating well, she said.
Previous research has also shown that children do better at exam time when they have been offered the choice of a healthy breakfast.
A new book by American author Paul Kramer entitled Maggie Goes on a Diet which charts the success of a school girl after she has lost weight has been greeted with anger on internet forums.