Public health experts are calling for a tax on sugary drinks like soda in an attempt to curb the obesity epidemic plaguing North America.

Research has linked the consumption of sugar-sweetened beverages to a higher risk for obesity, diabetes and heart disease.

To reduce these risks, and reduce the associated health-care costs, a group of public health officials writing in the New England Journal of Medicine proposes a tax of one per cent per ounce for drinks that contain added sweeteners.

The proposal says another option could be to tax beverages that exceed a specific threshold of grams of added sweetener (for example, one gram of added sugar per 30 ml).

A consumer who normally drinks a 591 ml can of soda per day and switches to a drink below that threshold would consume about 174 fewer calories per day, the experts say. And a one per cent per ounce tax on sugar-sweetened beverages could raise as much as US$14.9 billion at the federal level in the first year alone, they predict.

The authors admit that the exact effect of such a tax would not be known until it is implemented. However, revenue generated could be used to fund obesity-prevention programs and other public-health initiatives.

"The science base linking the consumption of sugar-sweetened beverages to the risk of chronic diseases is clear," the authors conclude. "Escalating health care costs and the rising burden of diseases related to poor diet create an urgent need for solutions, thus justifying government's right to recoup costs."

According to the proposal, studies show that consumption of sweetened beverages has doubled in a number of countries around the world.

A recent study from the American Heart Association found that Americans consume 22 teaspoons of added sugar per day, much of it from soft drinks and candy. Added sugar comes from sweeteners and syrups that are added to foods during processing or by consumers at the dinner table.

The Association recommends that women get no more than six teaspoons of added sugar per day, while men get no more than nine teaspoons.

Statistics Canada data released this summer suggests that consumption of soft drinks among Canadians fell from 76.4 litres in 2007 to 73.2 litres in 2008. However, refined sugar consumption jumped by 1.0 kg in 2008, to 23.1 kg.

Current taxes not enough

According to the NEJM article, 33 U.S. states already tax soft drinks, to a mean tax rate of 5.2 per cent. However, the experts argue that the taxes are not significant enough to reduce consumption, and the funds raised do not fund health programs.

The experts say that a one per cent per ounce tax would increase the cost of a 591 ml soft drink by 15 to 20 per cent.

By their estimates, such an increase would result in a between eight and 10 per cent decrease in consumption of sugary beverages. This reduction would likely lead to weight loss and a reduction in disease risk, the authors conclude.

While they admit that a tax on soft drinks won't eliminate obesity, they say it will help as part of a multi-pronged approach to the problem.

While the debate is ongoing in the United States, Dr. Yoni Freedhoff of Ottawa's Bariatric Medical Institute, says he is not aware of any formal talks about a soda tax in Canada. But he thinks it's a great idea.

"Could we use a tax on pop? Certainly," Freedhoff told CTV News.

"Taxing sugary beverages, if it decreases consumption and at the same time raises money that can be used for improving the health of society, I think that's a great idea. Certainly we don't need sugary sweetened beverages to survive."

On the other side of the debate, the Canadian beverage industry says the public has no appetite for the tax, and it would likely do little to curb bad eating habits.

"We agree that obesity is a complex health problem," said Refreshments Canada president Justin Sherwood. "However, taxing only one product will not make a difference."

With a report by John Vennavally-Rao in Toronto