The review found most schools provide good quality meals
Head teachers in England are being urged to ban packed lunches to increase the take-up of school dinners and promote healthy eating.
A government-commissioned school food review by two founders of the Leon restaurant chain says take-up is low at 43% despite huge quality improvements.
The authors of the School Food Plan say packed lunches are nearly always less nutritious than a cooked meal.
And heads are being urged to lower the price of lunches to boost take-up.
This might include providing subsidised meals for reception classes in primary schools and Year 7 classes in secondary schools, the report says.
The Department for Education ordered the review by restaurant founders Henry Dimbleby and John Vincent into the state of school meals in 2012 following strong criticism from Jamie Oliver.
Seven years earlier, the chef had led a successful campaign to ban junk and processed food from school canteens. This resulted in tight nutritional guidelines and healthy eating policies for those bringing packed lunches.
But in 2011 he claimed that standards were being eroded because academies and free schools were exempt from national nutritional guidelines.
This new review concludes that most schools do provide good quality food but that the proportion of children eating them is not high enough.
It suggests heads ensure that packed lunches are not more exciting than school lunches, and that items such as sugary drinks, crisps and confectionery be forbidden from lunch boxes. In reality many schools already have healthy packed lunch policies banning such items.
And they are being warned to watch what is being served at mid-morning break, when some children are said to fill up on pizzas, panini or cake.
Packed lunches are understood to be banned in a just a very small number of schools, but the DfE insists it is possible.
General Secretary of the National Association of Head Teachers Russell Hobby said he felt it probably was not feasible for schools to ban packed lunches.
He thought it was right, instead, to focus on making school meals more attractive in terms of cost and access as well as nutritional content, taste and presentation.
He added: “It is hard for students to concentrate on learning when they haven’t eaten enough or when they’ve eaten the wrong things. The benefits from investing in decent cooked meals are huge: better learning and better habits later in life; a calm and sociable lunch hall also sets a tone for the rest of the day.
“In addition, increasing numbers of schools are growing part of their own food, and this can have a big impact on the children.”
The Association of School and College Leaders said it was important the plan related to academy schools as well as regular state schools.
Other recommendations include: after-school cooking lessons for parents and children, more schools to have stay-on-site rules for break and lunch time, and for teachers to be encouraged to sit in the dining hall with children.
The report comes as the obesity rate among children at the end of primary school has risen to almost one in five.
It claims only 1% of packed lunches meet the nutritional standards that currently apply to school food.