Fizzy drinks and other unhealthy snacks have been pushed out of a Dunstable school in favour of healthier alternatives.

In an effort to improve student's nutrition and classwork, Queensbury Upper School has swapped all 13 of its vending machines for The Green Machine, which sells a range of organic and natural drinks and snacks.

The school has opted for eight of the "green" units and, although they are used in around 200 schools around the country, it is the first time any school has replaced such a large number of machines in one go.

Head of sixth form Chris Nicholls said: "A lot of the teachers have been concerned about the effect of some of the things that children eat and drink, particularly fizzy drinks, because they are concerned it makes them hyperactive."

He added: "We try to do everything we can to make learning better in the school and make it easier to learn, but some of the things they eat and drink seem harmful for that."

The Green Machine has been developed by the Organic and Natural Food Company and sells products which are additive-free, including crisps, chocolate and bottled water.

It is hoped the range of more healthy snacks will help improve concentration in students and encourage them to think about what they eat.

Barry Smethurst, managing director of the Organic and Natural Food Company, said: "We have long believed that school children were getting a poor deal from vending, nutritionally and ethically and also in terms of product quality.

"Our goal has been to provide a range of products that meet high criteria in each of these areas but which also tastes good enough to be the first choice for kids."

Chris Nicholls said that although the snacks in the new machine were slightly more pricey than those in the previous vending machine, he thought students would be happy to fork out.

He said: "We've tried doing some taste tests and we think they will be prepared to pay the higher prices."