The head teacher of a Falkirk high school has said a ban on pupils leaving school grounds during their lunch hour is helping them to stay healthier.
Burger vans must sell healthy options to secure trading licences
Andy Mimnagh, the head at St Mungo's, said keeping S1 to S4 pupils within the school during lunch time meant they were eating better and were safer.
Councillors in the local authority also recently voted to tighten licences for burger vans operating near its schools.
The move comes as the council aims to improve local health.
Chip vans and other fast food stalls that apply for licences to sell food near the area's schools must also now offer healthy foods to secure their trading licence.
The Scottish Executive began its three-year Hungry for Success initiative in 2004 to ensure healthier ingredients were used in school meals.
'Impact on pupils'
The scheme prompted St Mungo's to enlist the help of nutritionists who restricted chips to once a week and banned fizzy drinks.
Staff can also monitor what the pupils buy from the cafeteria thanks to a new computer system and can alert parents if there is cause for concern.
Parents whose children attend the school are told of the 'lunch lock-in' during the enrolment process.
Chips can now only be served in the school once a week
Mr Mimnagh said the system had proved popular with parents and pupils alike.
He said: "In Scotland we have a history for being unhealthy and the best way to deal with that is through education.
"In all the time that we have been doing this, no-one has ever come back and said they don't agree.
"Basically if we're going to keep pupils in the school then we have to give them good food."
A spokesman for Falkirk Council said there could be an expansion of the arrangement to cover other schools in the area.
He added: "We've invested a great deal in developing Hungry For Success across all our schools and we are determined that this and other support initiatives maximise the impact on our pupils."