Schools should prevent pupils from leaving school grounds during lunchtime to keep them away from nearby fast food outlets, a government trust said Friday.
The School Food Trust believes that with a "stay-on-site policy" during lunch times, pupils will be encouraged to eat a healthy meal in the school canteen, instead of opting for a fast food alternative at the local chip shop.
Research carried out by the trust -- which was established in 2005 to promote the education and health of children by improving the quality of school food -- found that in some places in the country, children have access to over 40 junk food outlets near their secondary school.
Brighton and Hove topped the league table with 46 fast food outlets per secondary school, twice the national average of 23 per school.
Fellow seaside towns Blackpool and Kingston-upon-Hull did little better with 40 outlets per school.
According to the trust, these takeaway outlets and sweet shops often directly target school students with special lunch deals.
As a result, "some school canteens are struggling to compete against their less healthy rivals," the trust said, adding that lunches with low nutritional value can reduce a pupil's ability to concentrate and learn during the afternoon.
Judy Hargadon, chief executive of the School Food Trust said: "At the moment school canteens have to compete with a myriad of takeaways, chippies, and sweet shops for pupils dinner money.
"The problem is that this is damaging their long term health, and is also threatening the viability of school lunch services ," she added.
The trust will now spend the coming months looking at ways that schools and local authorities can combat the temptation posed by junk food outlets.
Headteachers, although supportive of the trust's suggestion, have warned that a stay-on-site policy would be difficult to enforce.
John Dunford, general secretary of the Association of School and College Leaders, told the Press Association: "It is very difficult for some schools because of the sheer number of entrances and exits many have to watch to make sure children stay in at lunchtime.
"It is even more difficult for schools in the middle of towns. In principle, it is a good idea, but it could be very difficult to put into practice."
Separate research released by the trust said that 90 percent of over 1,000 parents questioned thought schools should adopt a stay-on-site policy, with 67 percent agreeing that children would eat more healthily if they were not allowed to leave school at lunch time.
The School Food Trust league table for fast food shops per secondary school:
10 WORST AREAS