Effect of taxes and subsidies on food: understanding the evidence

Article type
Authors
Michea V1, Vidal C1, Caro P1, Hoffmeister L1
1Escuela de Salud Pública, Universidad Mayor
Abstract
Background: the world plan of action for the prevention and control of noncommunicable diseases 2013-2020 of the World Health Organization (WHO) recommended the prevention of obesity and overweight through economic tools, such as taxes and food subsidies. During the last decade, the interest of public policies related to this type of strategy has increased because it is possible that they affect the purchase intention and the food consumption of the population.

Objectives: to evaluate the quality of evidence of the effect of taxes on unhealthy foods and subsidies on healthy foods in the change of food purchases.

Methods: two independent review authors conducted manual searches of Pubmed, Lilacs and Cochrane Library databases from 2009 to March 2019, with appropriate terms (financial, nutritional and outcomes terms) and their combinations, retrieving experimental studies and systematic reviews in English and Spanish. Two review authors completed the data extraction and made an outcome list of selected studies. We evaluated quality factors of the evidence for each study: risk of bias, inconsistency, direct evidence and imprecision. Additionally, we considered publication bias and factors that increase quality. The analyses were performed with GRADEpro.

Results: we found a total of 2992 publications and identified 143 relevant studies based on titles. Based on abstract information, 30 studies met the criteria established for this review. In the experimental studies we found two types of methodology to evaluate taxes and subsidies: a) use of a virtual supermarket and b) evaluation of purchase databases. Currently, we have reviewed part of the studies, which shows that taxes (between 12% and 25%) and subsidies (12% and 25%) modify intention to purchase. However, quality of evidence is low to moderate for the moment.

Conclusions: taxes and subsidies are likely to be an effective intervention. The studies support the efficacy of subsidies to increase consumption of healthy foods; and taxes to reduce the consumption of beverages and unhealthy foods, although the quality of evidence is low to moderate.

Patient or healthcare consumer involvement: this study doesn’t include a direct patient or healthcare consumer involvement.