New research from the Universities of Oxford and Reading in the UK suggests that introducing a 20% tax on sugar-sweetened drinks could help in the battle against obesity. This is according to a study published in the BMJ.

The researchers estimate that the tax would reduce the number of UK adults who are obese by 180,000 (1.3%) and reduce the number of people who are overweight by 285,000 (0.9%).

There has been previous evidence linking the consumption of sugary drinks to obesity. Late last year, Medical News Today reported on a study suggesting that people who regularly consume sugary drinks are genetically more susceptible to becoming obese or overweight.

According to a National Health and Nutrition Examination Survey conducted between 2005 and 2008, 50% of the US population consumes sugar-sweetened drinks on any given day, and 25% consume at least 200 calories - the equivalent to a can of cola.

Sugary drink tax 'may encourage healthier alternatives'

The overwhelming evidence linking sugary drinks to weight gain prompted the researchers to determine whether a sugar-sweetened drinks tax in the UK could reduce the problem.

"The idea of a tax on sugar-sweetened drinks is seen by many governments and health organizations as a way to reduce their consumption," Adam Briggs, of the University of Oxford and joint-first study author, told Medical News Today.

"The effect of such a tax in the UK had not previously been estimated and hence we set out to do this."

Briggs noted that the team chose to estimate the effects of a tax on sugar-sweetened drinks in particular, not only due to the health problems linked to them, but also they believed the tax would prompt the general public to move to healthier drink alternatives.

"The typical substitutes for sugary drinks - diet drinks, milk, tea and water- tend to be less harmful," he said. "Whereas we are less sure what people would substitute confectionary with if its price went up. Drinks tend not to suppress appetite, so we overconsume calories. This effect is probably less pronounced with confectionary."

Drink tax 'could subsidize health foods'

To reach their findings, the research team analyzed data from surveys of grocery purchases, drink consumption and the price of drinks, and body mass index (BMI) and drink population.

From this, the researchers were able to estimate that a 20% sales tax on sugar-sweetened drinks may help to combat obesity - particularly in those aged between 16 and 29, since this age group is the highest consumer of sugar-sweetened drinks.

Furthermore, the researchers estimate that the tax would be expected to raise £276 million ($442 million) a year, which they say "could be used to increase NHS (National Health Service) funding during a period of restrictions or to subsidize foods with health benefits, such as fruit and vegetables."

Briggs explained the estimates to Medical News Today:

"Our research indicates that the potential reduction in the number of obese adults in the UK would be 180,000, with the greatest effects seen in young people.

Our confidence intervals around this are 110,000 to 247,000, meaning we would expect the true value to be somewhere between these figures. The equivalent figures for obese and overweight people are 285,000, with confidence levels between 201,000 to 364,000."

The confidence intervals represent uncertainty in the price elasticity values they used - how the amount of something purchased changes with price, Briggs explained. He noted that this is where the greatest amount of uncertainty was within their model.

Tax 'should be introduced in more countries'

In an editorial linked to the study, Jason Block, assistant professor at Harvard Medical School in the US, says that the 20% sugar-sweetened drink tax could work in reducing obesity, and that more countries should adopt a similar strategy and measure the results.

"Econometric modelling studies are important and helpful but provide projections rather than measures after actual policy change. We now need policy makers to act and provide opportunities for real world evidence on a 20% tax on sugar-sweetened drinks," he says.

The next steps from this research, Briggs said, will be to look at the impact of a 20% sugar-sweetened tax in population groups that are defined by the consumption level of sugar-sweetened drinks.

"It would also be important to try to characterize the effect of any negative publicity surrounding sugar-sweetened drinks arising from a tax," he added.

"Finally, the response from industry of this type of tax is unclear. Ideally, a government will introduce a tax of this nature allowing for proper population level evaluation as a natural experiment."

Earlier this year, Medical News Today reported on a study suggesting that soft drinks may make children more aggressive and distracted.