A 20 percent tax on sugar-sweetened drinks would result in widespread, long-lasting public health benefits and significant health cost savings, an estimated $400 million a year and reduce annual health expenditure by up to $29 million, according to a computer model.

"Our modeling scoped the effects over the lifetime of adult Australians alive in 2010," says University of Queensland School of Public Health researcher Dr. Lennert Veerman. "We found there would be 800 fewer new Type 2 diabetes cases each year once the tax was introduced. After 25 years, about 1600 fewer deaths would occur each year, with heart disease accounting for the largest share of this postponed mortality. There would be 4400 fewer people with heart disease at that time and 1100 fewer people living with the consequences of stroke. In effect, Australians would enjoy about 170,000 healthy life years that they would not have otherwise."

The study defined a sugar-sweetened beverage (SSB) as a non-alcoholic drink with added sugar, including carbonated soft drinks and flavored mineral waters. Fruit juices, fruit drinks, energy drinks, milk-based drinks and cordials were excluded.

It sounds terrific but it relies on one key premise; that fat people who never exercise will suddenly eat less and exercise if soda and fruit juice is taxed more.

Veerman said overall health care cost savings would rise over the first 20 years of the tax and then stabilize at about $29 million a year. Previous estimates have claimed that a 20 percent tax (based on product price rather than on the amount of sugar in the product) could reduce total energy consumption by about 10,000 kJ per person per year, cutting body weight by 0.93 kg and costing household an average of $17.

"Policymakers have cited limited available evidence as a barrier to policy progress in the area of taxes on unhealthy foods, so we expect the detail in our study will be useful to them," Veerman said.

Victoria's Obesity Policy Coalition Executive Manager and study co-author Ms. Jane Martin said sugary drinks were the largest source of added sugar in Australian children's diets. "With one in four children and 67 per cent of adults now overweight or obese, we need decisive action by government to address the growing health burden of overweight and obesity in this country.

"Australian research has shown that two-thirds of respondents (65 percent) were in favor of a tax on soft drinks if the money was used to reduce the cost of healthy food."

The cost to government of implementing the tax was estimated at $27.6 million, but in a computer model reduced health care expenditure would pay back the cost of legislation and monitoring the tax more than 14 times.

"The greatest effects are likely to be seen in young people, who are the highest sugary drinks consumers," Veerman said. 

The paper was published in PLOS ONE.