In the UK, more than 70 per cent of adolescents consume carbonated drinks on a regular basis, and in a bid to understand the carbonated drinks factor in obesity, scientists at Bournemouth Hospital chose to target this group with a simple message.

Over a school year in a randomised controlled trial 644 children aged 7-11 years completed three day diaries on drinks consumed at baseline and after twelve months.

Anthropometric measurements such as height, weight, waist circumference and body mass index, were taken every six months.

The children in the intervention group attended a one hour session for each class, each term. These children were given a simple, uncomplicated message that decreasing sugar consumption would improve their overall well-being and that reducing the consumption of carbonated drinks would also benefit their dental health.

After twelve months, consumption of carbonated drinks (measured over a three day period) decreased by 0.6 glasses a day (average glass size 250 ml) in the intervention group, while consumption in the control group increased by 0.2 glasses per day.

In addition, after twelve months, the percentage of overweight and obese children had increased in the control group by 7.5 per cent, compared with a decrease of 0.2 per cent in the intervention group.

"A school based educational programme aimed at reducing consumption of carbonated drinks to prevent excess weight gain in children aged between 7-11 years was effective," conclude the authors.

Full findings are published in the British Medical Journal.