Calls for taxes on sugar-sweetened beverages (SSB) by health professionals and advocates continue to occupy news headlines. Seattle recently joined the growing list of U.S. cities that are experimenting with a tax on SSBs, while Cook County (Chicago) repealed a similar policy after only two months. Advocates of the tax point to studies using economic modelling, which paint rosy pictures of increased tax revenues, decreased SSB consumption and significant health impacts, to argue for the value of this strategy. Although much more empirical research is needed to determine long-term effects of taxing sugar-sweetened beverages, the existing empirical evidence suggests little effect on SSB consumption or health. This is not surprising given that people can purchase SSB from neighboring municipalities, order them from online retailers, substitute from newly taxed beverages to other unhealthy beverages, or switch to a generic brand of soda. Wellness, which draws heavily from self-determination and salutogenesis theories, provides insight into how professionals might think more constructively about nutrition policy.
The Rational vs. The Evidence
Taxes on sugar sweetened beverages are not new and have been implemented in many areas in many different ways. Thirty-four states currently have a sales tax imposed on soda sold in grocery stores, and 39 states tax vending machine sales. The most prevalent argument in support of levying a sugar-sweetened beverage excise tax (on top of any existing sales taxes) is the potential impact on public health. The CDC suggests that 49% of American adults drink SSB on a daily basis, with the average consumption of 149 calories. Soda and sugar-sweetened beverages have been implicated as a major source of excess calories and sugar, leading to weight gain, diabetes, and dental caries. Advocates argue that an excise tax on SSB will encourage people to decrease their SSB consumption, leading to significant improvements in weight and subsequently health.
But at what cost? Are the actual changes in consumption or health outcomes substantial enough to be considered worthwhile? How sustainable or long-lasting are these changes in consumption? And are there other programs or policies that would lead to more significant health outcomes and have a societal or individual cost that is equivalent to or lower than a SSB tax?
There is little evidence to support the claim that SSB taxes have significant influence on consumption. Although SSB tax supporters cite several studies that estimate 7.9%-21% decreases in SSB consumption, with the greatest impact occurring among low-income individuals, resulting in an estimated 30 fewer ounces purchased each week per household. However, most of these studies have significant limitations that constrain their ability to make substantive conclusions about SSB consumption impacts.
The first important limitation is that even if consumers decrease their consumption of SSB, the studies do not account for the substitution effects that a randomized field experiment shows increases the consumption of water, milk (flavored and unflavored), juice, generic brands, beer, and milkshakes or yogurt smoothies. Consumers may also choose to cut costs in other parts of their household budget to cover the increased cost of SSB or shift their purchases to stores in neighboring areas or online retailers. Most studies do not account for any of these substitution effects.
The second major flaw with studies on SSB taxes is that most do not control for the considerable overall downward societal trend in soda consumption over the past two decades or the effects of tax campaigns on social norming. This is critical since SSB consumption has been decreasing at a rate of nearly 1% a year since 1998 as people recognize the adverse health effects of consuming large amounts of added sugar.
Lastly, the sampling and analytical methods in some studies have been criticized for inflated demand elasticity estimates or weak sampling strategies. Therefore, it is not surprising that evidence based on self-reported soda consumption and household budget surveys suggests that a SSB tax did not significantly change in the case of Berkeley, CA, and that SSB taxes are predicted to decrease body weight by less than one pound in Mexico. So, if SSB taxes show lackluster impacts in practice, how can wellness professionals start to think differently about their policy advocacy?
Self-determination (SDT) is a theory of human motivation that begins with the assumption that people evolved to be “inherently active, intrinsically motivated, and oriented toward developing naturally through integrative processes.” Essential to the process of becoming aware of, and internalizing behaviors that move one closer to achieving their full health potential is fulfillment of an individual’s psychological need for competence, relatedness, and autonomy. In the context of food and nutrition, competence refers to developing individual and community capacity to identify, source, and prepare affordable, culturally-appropriate, healthy foods. Relatedness is about providing people with spaces and opportunities that create a sense of personal connection with others who value the health-promoting behavior. Lastly, autonomy means that people must recognize the value of a behavior for themselves and feel that doing this behavior is their own personal choice, free from the external coercion of incentives or penalties.
Taxes on sugar-sweetened beverages as a public health strategy violate the psychological need for autonomy. It is no wonder that many people perceive this tax as intrusive and react negatively toward the idea of health professionals and politicians coercing them to make particular decisions about what they eat and drink. Furthermore, these policies do not support cultivation of competence or relatedness. In this way, SSB taxes undermine self-determination. Public health education campaigns have contributed to a greater societal awareness of SSB adverse health impacts and, like the case of tobacco, contributed to individuals making autonomous choices to decrease their SSB consumption, without the excise tax.
Salutogenesis and Positive Health
Avoiding a bad behavior does not necessarily lead to the existence of good behavior. This subtle aspect of human behavior is the key to framing health strategies that enable people to learn how to live fully if we really mean it when we say “health is more than just preventing disease”. Salutogenesis refers to proactively generating full health potential. The key concept here is “potential”. Health approaches based on salutgenesis study the origins or causes of health. This is conceptually different that the traditional pathogenesis approach which seeks to understand the origins or causes of disease and design interventions that aim to reduce risk and avoid problems.
Reducing disease risk is important, but it is not the same as cultivating health potential. Sugar-sweetened beverage taxes respond to a situation that threatens to cause disease. However, decreased SSB consumption does not inherently lead to healthier eating patterns that include more fruits, vegetables, legumes and whole grains (causes of health). Without policies that enable the conditions for people to cultivate healthy diet patterns (e.g., living wages, shorter work weeks, access to quality fresh produce, cooking skills, affordable healthcare), SSB taxes are not likely to produce better eating habits.
Is there an appropriate use of SSB taxes?
Food policy initiatives warrant special attention because of their ability to cause great benefit or great harm to society. In some cases, regulations that restrict individual choices are necessary to support public health. Although SSB taxes may only have a trivial influence on consumption habits, they may have other important goals, such as providing subsidies for fresh produce or nutrition education, which may be justifiable to promote wellbeing by bring people together, build competence, and support autonomy in nutrition decision-making. Some SSB tax policy initiatives propose using revenue to fund nutrition education and fresh produce subsidies.
This strategy is not without challenges of its own since the revenue typically goes to the city’s general fund for use on whatever programs the city council ultimately decides to fund. In practice, ear-marking tax revenue for specific purposes is politically challenging. However, if the goal is for consumption of SSB to decrease, that also means revenue will decrease. In fact, many cities that implemented an SSB excise tax are reporting lower than projected revenues. For SSB taxes to generate sufficient revenue to fund public health programs, SSB consumption must remain stable or new sources of revenue must be found. A Catch-22. Finally, it is important to consider whether or not the same ends could be financed through a progressive tax that is less burdensome to low-income populations.
Drawing on the works of Antonovsky, referenced by Becker, Glasscoff, and Felts, we can adapt guidelines for developing strategies that advance health can help nutrition and public health professional advocate for salutogenetic public policies: (1) look at the public health data differently: instead of looking at populations who have succumbed to a problem like diabetes to find out what they are doing wrong, look at those who are succeeding and try to find out why they are doing well (what policies facilitate these behaviors?); (2) persuade policy-makers to consider outcomes related to success (e.g., greater consumption of fruits and vegetables), not just outcomes related to problem reduction (e.g., decreased soda consumption); and finally (3) stimulate the development of innovative policies that cultivate the conditions for these desired outcomes to occur. If SSB taxes are conceived as public health-promoting strategies in themselves, they have an obligation to be evaluated on the extent to which they will support self-determination and salutogenesis and be mindful about the place of health policies in relation to other aspects of well-being.