IT seems Jamie Oliver knows best, as new research suggests the celebrity chef’s healthy school dinners have helped to improve exam results and classroom attendance.

An independent study shows the performance of 11-year-old pupils eating Oliver’s meals improved by up to 8% in science and as much as 6% in English, while absenteeism due to ill-health fell by 15%.

The findings, from a report by the Institute for Social and Economic Research (ISER) at Essex University, vindicate the chef’s decision to banish fat-laden Turkey Twizzlers - since replaced with nutrient-rich foods such as coconut fish, and broccoli.

Many schools resisted Oliver’s Feed Me Better campaign due to the greater cost of the food. Some pupils would not stop eating junk food, and parents in one area were even seen passing burger and chips to children through school railings.

The ISER report focuses on schools in Greenwich, southeast London, where Oliver launched his healthy eating campaign with Channel 4 in 2004. This weekend Oliver said: “Even while doing the programme we could see the benefits to children’s health: it made them calmer and therefore able to learn. The results are fantastic - it’s the first time a proper study has been done into the positive effects of the Feed Me Better campaign. It strongly suggests we were right all along.”

Academics analysed the key stage 2 results of more than 13,000 children in Greenwich from 2002-7 to gauge the impact on performance of Oliver’s healthier meals. Pupils who sat exams in 2006-7 were on the new diet for at least 12 months, and after researchers had adjusted for an upward trend in pass rates, they found the number of pupils reaching levels four or five had risen by up to 8% in science, and 6% in English. There was also a small improvement in maths results.

The ISER study compared the Greenwich results with those of key stage 2 pupils in seven other London boroughs that did not have Oliver’s meals.

Michèle Belot, a research associate on the study, who allowed for pupils improving over time and for many other variables, was surprised by the speed of improvements and could find no explanation for the results other than Oliver’s meals.

She said of the campaign: “It obviously made a real difference to some children’s lives.”

During the campaign, Oliver hired nutritionists who found most school meals contained less than half the daily recommended amount of iron, a mineral that improves children’s cognitive development and concentration. In response, the chef introduced iron-rich foods such as red meat, pulses and green vegetables, while reducing sugar and saturated fat by eliminating processed foods such as Turkey Twizzlers.

Oliver’s new menus, adopted by 81 out of 88 primary and secondary schools in Greenwich, included more pasta and fresh fruit, plus dishes such as Mexican bean wraps, chickpea soup and vegetable chow mein. Hayley Franklin, 11, from John Roan school in Blackheath, southeast London, said: “The new dinners give me much more energy, for longer, so I can concentrate on work through the whole day.”

Trisha Jaffe, head teacher of Kidbrooke secondary school - the first school to test Oliver’s menu, said: “Because the children aren’t being stuffed with additives, they’re much less hyper in the afternoons now.”

Greenwich council committed more than £90,000 in one year towards retraining its dinner ladies, and has increased the subsidy towards each child’s meal from 33p to 81p.

In 2005, Oliver secured £220m of government funding for healthier menus, and the following year the School Food Trust introduced new national guidelines for healthier school meals.

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