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MEI in the Media


15 November 2012November 15, 2012

Are Soda Taxes A Cure For Obesity?

Economic Note about the ineffectiveness of a soda tax

Are Soda Taxes A Cure For Obesity?

Roughly one in four Canadian adults is obese ‒ with the percentage of obese Canadians continuing to rise. Every year, obesity results in billions of dollars in preventable health care costs for governments, taxpayers, employers and families. To reverse this trend, many public health advocates, among whom the Ontario Medical Association, have been calling for various types of taxes and regulation on fatty and sugary foods. These include a "soda tax," that is, a tax on soft drinks and other sweetened beverages.

Media release :: A tax to protect public health?


Related Content

The Case Against Taxing Soda (Huffington Post, November 15, 2012)

We can't tax our way to better health (National Post, November 15, 2012)
Mention of the MEI Economic Note in a French report (Radio-Canada, November 14, 2012) Interview (in French) with Jasmin Guénette, Vice President of the MEI (ARGENT business news network, November 15, 2012)

This Economic Note was prepared by Dr. David Gratzer, physician, author and senior fellow at the MEI, with the collaboration of Jasmin Guénette, vice president of the MEI.

Roughly one in four Canadian adults is obese - with the percentage of obese Canadians continuing to rise. Every year, obesity results in billions of dollars in preventable health care costs for governments, taxpayers, employers and families.

To reverse this trend, many public health advocates, among whom the Ontario Medical Association, have been calling for various types of taxes and regulation on fatty and sugary foods.[i] These include a "soda tax," that is, a tax on soft drinks and other sweetened beverages. Although per capita consumption of soft drinks in Canada has already fallen by 32% between 1999 and 2011 (see Figure 1 on, they believe that this will reduce obesity by driving consumers away from them in even greater numbers.

In early 2012, a spokesperson for Federal Health Minister Leona Aglukkaq rejected the idea of a Canada-wide soda tax.[ii] Still, a Public Health Agency of Canada poll released this year found that 40% of Canadians would support a soda tax if funds raised were used to fight childhood obesity.[iii] Is there any indication that such a tax would be effective?

Soda tax proponents generally call for an excise tax, imposed directly on manufacturers and wholesalers of all sugar-sweetened beverages. In a widely-cited 2009 paper in the New England Journal of Medicine, Dr. Kelly Brownell and other proponents of a tax on sweetened beverages argued that an excise tax would be "simpler to administer" than a retail tax.[iv] A retail tax would be less effective, since it would only raise the cost to consumers after the purchase decision was made.

For such a tax to have an impact, a given increase in price has to lead to an appreciable fall in the overall quantity of soda demanded by consumers, which must in turn lead to population-wide weight loss. This is the basic assumption of soda tax proponents. Dr. Brownell projects that a modest tax would cut net U.S. calorie intake "by a minimum of 20 kcal [calories] per person per day." A study by the U.S. Department of Agriculture projects an average weight loss of roughly four pounds over a year from a 20% soda tax.[v] A 2012 estimate in Health Affairs projects that a smaller tax should lead to enough weight loss to extend 26,000 lives over a ten-year period.[vi]

These projections have been disputed by other scientists because they are too broad and are based on methodologically weak assumptions. In a Lancet article, researchers explain that public health advocates usually overstate the potential weight loss estimates from anti-obesity policy interventions, because they rarely take into account the fact that a person's metabolism will adjust to minor reductions in calorie intake.[vii] However, optimistic assumptions are not the main problem with these scenarios.

A narrow focus

Even if consumers were really going to cut their consumption of soda and other sweetened beverages appreciably following a price increase, several limitations make soda taxation a poor policy choice. The first one is the excessively narrow focus of such a tax.

Soda critics often cite a particular US study in a manner that overstates soda's share of the problem. For example, a Canadian anti-soda organization's website claimed that "a 2004 study found that soft drinks are the largest single contributor of caloric intake in the US."[viii] This is untrue.

In fact, the study in question was the National Health and Nutrition Examination Survey (NHANES). The survey's 2003-2004 data and subsequent reports found that soda was just one unhealthy component among many, when consumed in too large quantities, in the American diet. Grain-based desserts, yeast breads, as well as chicken and chicken mixed dishes all provide a higher share of dietary calories than did soda, energy and sport drinks combined in the 2005-2006 NHANES data. The latter accounted for 5.3% of total calorie intake.[ix] A separate 2011 study of dietary changes finds that cuts to potato chip or potato intake were associated with greater weight loss than a similar reduction in soda intake.[x]

Canadians for their part get less than 2.5% of their calories from soft drinks.[xi] In most age and gender categories, Canadian adults consume more coffee or beer than soft drinks.[xii] A large Tim Hortons "double-double" coffee has 270 calories, while a "triple-triple" has 405 calories. The chain's popular iced cappuccino rings in at 470 calories for a large serving with cream. By comparison, a 591 ml bottle of sugar-sweetened Coca-Cola (equivalent to a large cup of coffee) has 260 calories.[xiii]

Measured on a calories-to-volume basis, these three Tim Hortons drinks are therefore more "sugary" than a bottle of Coca-Cola. But only one - the iced cappuccino - would presumably be taxable under an excise tax model, since sugar and cream are added at the point of sale for the others (see Table 1 on

Another reason activists like to focus on soda and sweetened beverages is that they are a large source of added sugar, that is, refined calorie-containing sweeteners added to foods and beverages during processing or preparation. However, obesity is not caused by "added sugar" or "wasted calories." Such terms create a false impression. Given that pizza is rich in sodium and solid fats, 400 calories worth of pizza with "no added sugar" could easily be less healthy than the same calories from a large soda.

A moving target

Another limitation is that even if we wanted to broaden the scope of the tax, it would be difficult to target the right types of drink.

Taxing the manufacture of all sweetened drinks - the preferred solution of most soda tax advocates - would also capture non-carbonated drinks, including flavored milks, sweetened teas, fruit smoothies or otherwise healthy juices like sweetened cranberry juice. Beverages that contain essential nutrients (including calcium, vitamin C and vitamin E) would be taxed. Lawmakers could avoid this dilemma by taxing only carbonated beverages. However, this would leave many calories out of the intervention.

New York City has seen this dilemma in action on a related issue: serving size regulation. As drafted, the new regulation banning any sweetened beverage over 16 fluid ounces has several unintended consequences. One key flaw is how sweetness is defined. The rules define "sweetened" to mean any drink that has more than 25 calories per 8-ounce serving.

As the co-founder of the Honest Tea line of beverages explained,[xiv] the company's most popular product is an organic Honey Green Tea, which contains 35 calories per 8 ounces in a 16.9-ounce bottle. The slogan, "Just a Tad Sweet" is printed right on the bottle. The company selected this serving size because it was standard for nearby bottlers. Honest Tea can now either take its (low-calorie) tea out of the New York City market, or it can retool its entire production line and distribution system to sell bottles that are a bit smaller, all because its product has only a few more calories per unit than an arbitrary sweetness threshold. One way or another, this won't reduce the rate of obesity in New York City.

Calorific Substitution

All other things being equal, a consumer who is only encouraged to cut soda calories is likely to replace them with other foods and beverages. This is known as "calorific substitution." Soda tax proponents often understate this problem, and their estimates vary widely. In 2009, Dr. Brownell's "conservative estimate" was a calorific substitution rate of 25%. Others assume a 40% substitution rate.[xv]

Other studies of substitution rates are more pessimistic. One finds that substitution effects are so complex that poorly targeted food and beverage taxes "could actually increase weight."[xvi] Other researchers found that each additional 1% increase in state soft drink tax rates led "to a decrease in body mass index (BMI) of 0.003 points" - basically a rounding error.[xvii] Even a very large tax increase might therefore have no perceivable effect. The problem is that the "reduction in soda consumption is completely offset by increases in consumption of other high-calorie drinks."[xviii]

Political Limits

To cut soda consumption, any tax must be high enough to shift consumer behavior - yet higher taxes reduce the likelihood of political approval. Dr. Brownell and his colleagues called for a tax of one penny per sweetened fluid ounce. In Canada, this formula would raise the price of a standard can of soda by $0.12 per can, roughly 10%. Most observers argue that any anti-obesity tax would have to increase prices by 20% or more to significantly change behavior.[xix]

Recession-battered American voters haven't shown much enthusiasm for proposed soda taxes. In 2010, 60% of Washington State voters overturned soda, candy and bottled water taxes in a ballot initiative; the target of their wrath was an excise tax of just two cents per twelve ounces. British Columbia's HST backlash suggests Canadian voters could prove to be just as testy about proposals to raise consumer taxes, which, it should be noted, will hit lots of people who consume only moderate quantities of soda.

Higher taxes may also not deliver expected levels of higher prices for every product.[xx] Beverage companies will try to protect market share with discounts, loyalty programs, and other promotions. Governments would have to fix prices to counter this problem, again raising the political difficulty of controlling consumer, taxpayer and corporate behaviours in order to attain uncertain goals.


While heavy-handed taxes and regulations are popular in public health circles, there are better, more constructive options. American and British experiments have shown that positive financial incentives can be more effective at motivating people to achieve dietary and weight loss goals. We must also train and organize primary care providers to help patients see obesity as a preventable medical risk. Students are a captive market when it comes to school meals and school schedules. Public health advocates are right to demand healthier school meals and a return to regular physical education.

The obesity problem is real. There is little evidence, though, that a Canadian soda tax would be anything more than a politically-motivated tax, arbitrarily levied on a convenient scapegoat.


[i] The Quebec Coalition on Weight-Related Problems has advocated a soda tax for many years: The Ontario Medical Association recently called for higher taxes and graphic warnings on food with no nutritional value:
[ii] Sarah Schmidt, "Support high for junk food, soft drink tax," Calgary Herald, January 10, 2012.
[iii] Ibid.
[iv] Kelly D. Brownell et al., "The Public Health and Economic Benefits of Taxing Sugar-Sweetened Beverages," The New England Journal of Medicine, Vol. 361 (2009), No. 16.
[v] Travis Smith et al., "Taxing Caloric Sweetened Beverages: Potential Effects on Beverage Consumption, Calorie Intake, and Obesity," USDA Economic Research Service, No. 100 (July 2010).
[vi] Y. Claire Wang et al., "A penny-per-ounce tax on sugar-sweetened beverages would cut health and cost burdens of diabetes," Health Affairs, Vol. 31 (2012), No. 1.
[vii] Kevin Hall et al., "Quantification of the effect of energy imbalance on bodyweight," The Lancet, Vol. 378 (2011), No. 9793.
[viii] "Drop the Pop" is a voluntary effort to reduce soda consumption in the Canadian territories; their website is at
[ix] U. S Department of Agriculture, U. S. Department of Health and Human Services, Dietary Guidelines for Americans 2010, p. 12.
[x] Dariush Mazaffarian et al., "Changes in Diet and Lifestyle and Long-Term Weight Gain in Women and Men," New England Journal of Medicine, Vol. 364 (2011), No. 25.
[xi] See Didier Garriguet, Overview of Canadians' Eating Habits, Statistics Canada, 2004, Table 4.
[xii] See Didier Garriguet, "Beverage consumption of Canadian adults," Statistics Canada, November 2008.
[xiii] All Tim Hortons calorie estimates are drawn from the company's nutrition calculator, found online at The Coca-Cola calorie count was found online at
[xiv] Seth Goldman, "Mayor Bloomberg and Our 16.9-Ounce Tea," The Wall Street Journal, July 22, 2012.
[xv] Y. Claire Wang et al., op. cit., footnote 6.
[xvi] C. Schroeter et al., "Determining the impact of food price and income changes on body weight," Journal of Health Economics, Vol. 27 (2008), No. 1. The study specifically assessed the impact of a tax on "food away from home," another food category often selectively blamed for obesity outcomes.
[xvii] Jason M. Fletcher et al., "Can soft drink taxes reduce population weight?" Contemporary Economic Policy, Vol. 28 (2010), No. 1.
[xviii] Jason M. Fletcher et al., "The Effects of soft drink taxes on child and adolescent consumption and weight outcomes," Journal of Public Economics, Vol. 94 (2010), p. 967.
[xix] Dennis Campbell, "'Fat tax' on unhealthy food must raise prices by 20% to have effect, says study," The Guardian, May 16, 2012. Travis Smith et al. (op. cit., footnote 5) set the bar for an effective soda tax at 20%. Fletcher et al. (op. cit., footnote 17) go further, arguing that "even a relatively large increase of 18 percentage points. may not have a substantial effect on population weight."
[xx] Until recently, most papers, like Kelly D. Brownell et al. (op. cit., footnote 4) acknowledged potential political opposition but ignored any potential price impact of a marketplace response. To their credit, Travis Smith et al. (op. cit., footnote 5) noted the potential for unexpected price adjustments.


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