The study of more than 5,500 11-year-olds in 291 Nova Scotia elementary schools, conducted by Dr Paul J Veugelers of Alberta university, found that schools with nutrition programmes saw a 9 per cent reduction in overweight children and a 15 per cent drop in obesity. But 12 schools that combined healthy lunches with physical activity did even better.
Dr Veugelers said: "Some schools have focused on nutrition, but the most successful are those that have undertaken a comprehensive programme that bans junk food, introduces children to healthy foods and increases their physical activity."
Schools in Annapolis Valley, near Halifax, used to sell McDonald's hamburgers or Kentucky Fried Chicken for school lunches, but after the launch of a health-promotion project in 1997 some began to offer healthier options such as vegetable, tuna or chicken wraps, home-made macaroni cheese and a range of vegetables. Baked potatoes with cheese and sliced Nova Scotia apples - available in plastic bags - have become particular favourites.
Ismay Bligh, co-chair of the project, says that even slight increases in physical activity led to significant reduction in weight.
"We helped some schools to set up after-school volleyball and football games. We taught children hopscotch, skipping and other playground games, the aim being to get them moving around," she said.
Isaac Peill, an 11-year-old pupil at Port Williams elementary school, near Halifax, said he and his friends are not missing the fast-food options. "My favourite food here is the baked potato covered with cheese," he said.