From Coke to Coors: A Field Study of a Fat Tax and its Unintended Consequences


      Would the taxing of calorie-dense foods such as soft drinks help reduce obesity or lead to more nutritious lifestyles?

      Theory, Prior Research, Rationale

      This policy-level debate curiously neglects the contributions of behavioral economics to understanding consumer shopping behavior and the notion of tradeoffs.

      Study Design, Setting, Participants, and Intervention

      To examine this, a 6-month field experiment was conducted in an American city of 62,000 where half of the 113 households recruited into the study faced a 10% tax on calorie-dense foods and beverages and half did not.

      Outcome, Measures and Analysis

      Household sales of beverages were measured every trip and demographics were collected following the test period.


      The tax resulted in a short-term (1-month) decrease in soft drink purchases (p=.04), but no decrease over a 3-month or 6-month period (p = .24). Moreover, in beer-purchasing households, this tax led to increased purchases of beer (p = .03).

      Conclusions and Implications

      To nutrition educators, this underscores the importance of investigating unexpected substitutions. To public health officials and policy makers, this presents an important empirical result and more generally points toward wide ranging contributions that marketing scholarship can make in their decisions.