New research suggests that a tax on the amount of sugar in soft drinks could help fight obesity.

There is a growing concern that sugary drinks are a significant contributor to obesity due to their high sugar content and low nutritional value, leading policy makers to look for ways of reducing the amount of sugary drinks in diets.

"Taxing sugary drinks isn't a new concept, but given the immediacy of the global obesity problem, it's time we got creative with how we approach it," Dr. Evan Blecher, senior economist at the American Cancer Society, said in a statement. "We could get sharper effects from taxation if we tax the dose of an ingredient, like sugar, or calories."

For the study, Blecher drew comparisons between taxing tobacco, alcohol and sugary drinks, using South Africa as a case study. While a flat tax is a good approach to tobacco, it may not be the best way to encourage different habits when it comes to the consumption of alcohol and sugary drinks.

Based on his analysis of the implementation of the tobacco tax, he found that taxing by the number of cigarettes is the best approach. Translated to alcohol and sugary drinks, this would mean taxing by volume. However, taxing the dose of a particular ingredient -- the alcohol in alcoholic beverages or the sugar or calories in sugar-sweetened drinks -- could be a more effective way to reduce consumption. This may also incentivize drinks companies to offer low-calorie or healthier alternatives.

This dose approach to taxation has been effective at reducing the consumption of alcohol in South Africa, reducing the amount of alcohol consumed in beer by 12 percent since 1998. As well as being a possible approach for sugar-sweetened drinks, it could also be effective at controlling unhealthy food consumption, and even fuel consumption.

"Effectively, this is not that different from the conceptual understanding of carbon taxes -- the idea is to tax the dose of the pollutant to incentivize consumers and producers to use better technologies to reduce carbon," Blecher said. "We could use it as a mechanism for taxing fuel: at the moment all petrol is taxed at a flat rate, but different petrols release varying amounts of pollutants in to the atmosphere. Taxing according to pollutant production could be a new approach."

The findings are detailed in the journal Social Science & Medicine.