PUPILS should be banned from leaving school grounds during lunchtime to prevent them eating takeaways and junk food, public health experts have said.

The Glasgow Centre for Population Health (GCPH) made the call in response to Scottish Government plans to tackle obesity.

They said councils should consider 'onsite lunchtime policies' to stop youngsters eating takeaways or buying junk food.

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This would mean pupils were forbidden from leaving school premises unless they have express permission.

Figures show that 29 per cent of Scottish children and two-thirds of adults are overweight or obese.

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The GCPH experts said Scotland could follow the example of Sweden, where children also help prepare school meals.

They wrote: "In our research exploring the nutritional quality of food sold from outlets around selected schools, we found that fast food bought outside school is of very poor nutritional value and high in fat salt.

"Encouraging pupils to stay onsite is therefore likely to result in an improvement in the nutritional quality of lunch.

"In addition, pupils eligible for free school meals are disadvantaged where there is a culture of leaving school to buy lunch.

"Onsite lunchtime policies have the dual benefits of providing healthier, affordable food options without stigmatising those not financially able to purchase off-site lunches.

"We would like a review of the approach to food in schools."

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The Scottish Government is currently considering responses to a public consultation on its obesity strategy, which has proposed measures such as a ban on junk food price promotions and forcing food retailers including restaurants and takeaways to display calorie information on menus.