A systematic review of the effectiveness of food taxes and subsidies to improve diets: understanding the recent evidence.

There has been significant growth in political, public, media, and academic interest in taxes and subsidies to encourage healthy food consumption over the past 3 years. The present systematic review, including an assessment of study quality, was conducted on new evidence published between January 2009 and March 2012 for the effect of food taxes and subsidies on consumption. Forty-three reports representing 38 studies met the inclusion criteria. Two of these were prospective randomized controlled trials that showed price changes were effective in both grocery store purchasing (subsidy) and away-from-home food purchasing (tax) contexts. The most robust modeled studies (considering substitution) showed larger effects for taxes on noncore foods or beverages for which there are close untaxed substitutes (such as soft drinks or "unhealthy" foods, based on nutrient profiling). Taxes and subsidies are likely to be an effective intervention to improve consumption patterns associated with obesity and chronic disease, with evidence showing a consistent effect on consumption across a range of tax rates emerging. Future research should use prospective study methods to determine the effect of taxes on diets and focus on the effect of taxation in conjunction with other interventions as part of a multisectoral strategy to improve diets and health.