Head teachers should consider banning packed lunches and stop students leaving schools at lunchtime to buy fast food, a report for the Department for Education recommends.
The report says that take-up of school meals is only 43 per cent and while packed lunches remain popular, only 1 per cent meet the nutritional standards of school dinners, with many containing fizzy drinks, sweets and crisps.
The latest recommendations follow an attack on the quality of school dinners by celebrity chef Jamie Oliver. His campaign led to tougher nutritional guidelines and a clampdown on junk and processed foods like the infamous turkey twizzler in school canteens.
The report was drawn up by the founders of restaurant chain Leon, Henry Dimbleby and John Vincent.
Mr Dimbleby told BBC Radio's 4 Today programme that food standards in schools had improved since the "dark days of the turkey twizzler" but that take-up of schools meals was still too low.
"Packed lunches, and more than half of our children bring packed lunches into schools, two-thirds of those have crisps in them and two-thirds have confectionery in them," he said.
"The best schools, the schools with good food, find ways of making packed lunches the least exciting option."
The report adds that more children could be encouraged to choose school dinners if the price was lowered. It suggests the possibility of introducing subsidised meals for reception classes in primary schools and Year 7 classes in secondary schools.
"Canteens are a bit like a restaurant - if you're half empty, you're losing money, said Mr Dimbleby. "The more children you have in, the better food you can serve at a cheaper price."
He added: "We did a survey of 400 headteachers. Over 90 per cent believe strongly that food has a direct effect on academic achievement and behaviour."