Speaking at the Food Revolution event in Sydney on the weekend, celebrity chef and regulation proponent Jamie Oliver said he believed that soft drinks should attract a 15% tax in Australia.

The World Health Organization has recently called for fructose and sucrose consumption to be cut to only 5% of the total daily energy needs of both adults and children, and for soft drink consumption to be limited. But is a tax on soft drink the solution? Is it legally feasible? And more importantly, would it make any difference?

Have any countries had success with introducing a soft drink tax?

Yes. Last year Mexico introduced a nationwide per-ounce tax on soft drinks, and overall soft drink consumption has fallen since. A city-wide tax on soft drink sales was also introduced in the Californian city of Berkeley in January.

New York City mayor Michael Bloomberg tried to implement a ban on soft drinks over 450 grams but this was overturned by a judge after less than a year.

Similarly, a tax on foods with a fat content of over 2.3% saturated fat was also repealed in Denmark after a year in 2012. Lawmakers attributed the failure of the tax to the close proximity of Germany and Sweden, which did not implement such a tax and subsequently attracted Danish consumers.

What are the health risks associated with regular consumption of soft drinks?

There are a number of health issues associated with consuming drinks with added sugar. These include obesity, type 2 diabetes, some cancers, tooth decay and acid wear. Additionally, Rethink Sugary Drink suggests that one can of soft drink a day can lead to an annual weigh gain of 6.75kg.

Is 15% high enough to encourage people to give up their daily Coke habit?

Jane Martin, the executive manager of Australia’s Obesity Policy Coalition, says research suggests that taxes need to be “high enough to elicit population based behaviour change” and that a 20% tax would be more effective in stopping people from purchasing soft drinks. The coalition would like to see the revenue raised from the tax be used to create more healthy eating programs and improving the affordability of fresh food nationwide.

If there’s a soft drink tax will people find alternatives?

The proposed tax raises questions about where the line is drawn in terms of sweet beverages. Similar to the unpopular “alcopops” tax, which resulted in an increase in the sale of hard liquor and mixers in lieu of pre-mixed drinks, a soft drink tax could lead to a rise in the sales of cordials and syrups, which could be mixed with untaxed soda water to make fizzy drinks.

Joe Lederman, the managing principal of FoodLegal, a Melbourne-based food regulatory consultancy firm, says the proposed tax is “an untargeted approach”.

Would it be possible to pass such a law?

The issue was not raised in Monday’s taxation white paper and if it were to be introduced on a federal level, it would have to go through the law-making process, where the outcomes can be very hard to predict.  The lack of a majority in the Senate might also prove to be a hindrance.

Laws relating to taxation can be more difficult to pass, but like smoking legislation, taxes relating to health are more often than not well received.

How likely is success? 

“It hasn’t worked in the past with other products”, Lederman said. He also points out that there is always a “trade-off” between health, trade and environmental organisations, making the tax’s implementation and success a difficult process — either way, someone (and their lobby group) is going to be disappointed.

However, Martin praised Oliver’s attempt to bring awareness to the issue and believes that a soft drink tax “has a lot of potential”. The proposed tax could be used as a starting point for a greater national conversation on health that involves policies such as a mandatory food star rating system and stricter junk food advertising laws.

“Even a small change in behaviour has a major impact on public health”, she said.