Dear Editor
Evidence suggests that a wide-ranging tax on junk food combined with subsidies for healthy foods is a significant step forward in the goal of improving population health.(1) Yet, only fiscal policy via taxation of unhealthy food products is not a panacea for reducing the levels of overweight and obesity and must be complemented with other public health measures.
As Luke Taylor points out, Mexico provides important lessons. Although the tax on sugary drinks arguably reduced its consumption, the prevalence of overweight and obesity remains unaffected at least in the short run,(2) particularly in children.(3) Individuals and families swiftly adapt their consumption bundles,(4,5) managing to balance the increase in price of one good by reducing the consumption of other goods. Contrary to standard economic theory, tastes and preferences are endogenously shaped by the environment that restricts what type of products are available to consume. Therefore, the long-term effects of these taxes are uncertain on positively reshaping consumption patterns.
Rather than suggesting that taxing junk food is wrong, we argue that it must be accompanied by other complementary policy measures. Taxes affect price and quantity of targeted food items, but this only partially explains consumption patterns. Healthy consumption depends heavily on social determinants including the environment in which people live that encompasses the availability and affordability of healthy foods, access to information and education, and exposure to marketing as well as cultural norms. In addition, beyond medical or genetic factors, obesity is not only related to food choices but also to lifestyle, including physical activity, which will not be affected by taxation of junk foods. Another important consideration is the asymmetry of nutritional information between individuals and corporations, which is exploited in affect purchasing choices.(6) Some interventions to address these practices have been implemented – most notably the bans on tobacco advertising.(7) These measures best designed and derived from evidence which in turn requires focused research to clearly identify causal mechanisms of behavioral choices around obesity.
Fiscal policies can be a good start, particularly in populations that live in food swamps. However, for households in food deserts, including many resource-constrained parts of Latin America, taxation alone is a blunt instrument. Subsidies for healthy foods, incentives to build healthy and safe spaces for exercise, and incentives for local growing of fruits and vegetables should be considered.
Nutrition and food policy designed with an overwhelming focus on a single instrument, runs the risk of inefficacy, at best and at worst pushing the most disadvantaged, to deepen their poverty. A new social contract is needed in which economic policies go beyond narrow criteria of efficiency to a broader vision of population needs and a more desirable equilibrium with spillover benefits between health, equity and growth.
(1) Niebylski, M. L., Redburn, K. A., Duhaney, T., & Campbell, N. R. (2015). Healthy food subsidies and unhealthy food taxa%on: A systema%c review of the evidence. Nutri&on, 31(6), 787-795.
(2) Colchero, M. A., Salgado, J. C., Unar-Munguía, M., Molina, M., Ng, S., & Rivera-Dommarco, J. A. (2015). Changes in prices a_er an excise tax to sweetened sugar beverages was implemented in Mexico: evidence from urban areas. PloS one, 10(12), e0144408.
(3) Bernal-Serrano, D., Contreras-Loya, D., Choperena-Aguilar, D., Arreola-Ornelas, H., & Merino-Juárez, G. A. (2023). The effect of public policy on high BMI trends of Mexican children: an interrupted Ome series analysis. The Lancet Global Health, 11, S21.
(4) Clemens, M., & Röger, W. (2021). Temporary VAT Reduction during the Lockdown-Evidence from Germany.
(5) Aguilar, A., Gutierrez, E., & Seira, E. (2021). The effectiveness of sin food taxes: evidence from
Mexico. Journal of Health Economics, 77, 102455.
(6) Véliz, C., Maslen, H., Essman, M., Taillie, L. S., & Savulescu, J. (2019). Sugar, taxes, & choice. Has&ngs Center Report, 49(6), 22-31.
(7) Saffer, H., & Chaloupka, F. (2000). The effect of tobacco advertising bans on tobacco consumption. Journal of health economics, 19(6), 1117-1137.
Controlling obesity requires more than taxes on junk food