Importance: Fiscal policy is a promising approach to incentivizing better food choices and reducing the burden of chronic disease. To inform guidelines on using fiscal policies, including taxes and subsidies, to promote health, the World Health Organization commissioned a systematic review and meta-analysis of the worldwide literature on the outcomes of such policies for food products.
Objective: To assess the outcomes of implemented food taxes and subsidies for prices, sales, consumption, and population-level diet and health.
Data sources: Eight bibliographic databases were searched for peer-reviewed literature and 14 data sources along with governmental websites were searched for grey literature that were published from database inception through June 1, 2020. There were no language and setting restrictions.
Study selection: Only primary studies of implemented food taxes and subsidies were considered for inclusion.
Data extraction and synthesis: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline was followed. A 3-level random-effects model was used to conduct a meta-analysis of sales and consumption outcomes of fruit and vegetable subsidies. Other outcomes were analyzed in a narrative synthesis.
Main outcomes and measures: Study estimates in the meta-analysis were combined using a price elasticity measure for sales and consumption outcomes. Heterogeneity was assessed using the I2 statistic and τ2. Studies varied in how diet and health were measured.
Results: A total of 54 articles were included in the systematic review, of which 15 studies were included in the meta-analysis. Most food subsidies targeted fruits and vegetables and populations with low income, whereas the evidence on food taxes was primarily from the nonessential energy-dense food tax in Mexico. Sales of subsidized fruits and vegetables increased significantly, with an estimated price elasticity of demand of -0.59 (95% CI, -1.04 to -0.13 [P = .02]; 95% prediction interval, -2.07 to 0.90; I2 = 92.4% [95% CI, 89.0%-94.8%; P < .001]), suggesting inelastic demand. There was no significant change in the consumption of subsidized fruits and vegetables, with an estimated price elasticity of demand of -0.17 (95% CI, -0.49 to 0.15 [P = .26]; 95% prediction interval, -1.01 to 0.67; I2 = 76.2% [95% CI, 54.3%-87.6%; P < .001]). Food excise taxes were associated with higher prices and reduced sales. Evidence was limited on the differential outcomes of food taxes and subsidies across subpopulations.
Conclusions and relevance: Results of this systematic review and meta-analysis indicated that fruit and vegetable subsidies were associated with a moderate increase in fruit and vegetable sales. Further research is warranted to understand the implications of food taxes and subsidies for population-level consumption, diet, and health outcomes.