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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.

Research 2 from Business Source Premier. In addition, 55 papers from Google Scholar were judged relevant. Once duplicate references were removed, 62 remained. Thereafter, 41 papers were excluded following a full text review, leaving 21. The reference lists from three recent reviews [17][18][19] were also examined, yielding two further publications, and the details of one recently published study were obtained directly from a coauthor. 20 Finally, 24 studies were included in the current review (Fig. 1). AnalysisFor the purposes of the analysis, studies were classified according to: (i) the outcome assessed, such as the effect on food consumption or expenditure, body weight or health, (ii) whether they were modelling or empirical studies, and (iii) whether or not they were peer-reviewed. ResultsOf the 24 studies reviewed, 13 were from the peer-reviewed literature, including one published in an edited book, and 11 were published online, as summarized in Table 1 (available at: http://www.who. int/bulletin/volumes/88/8/09-070987). All were published between 2000 and 2009, and mostly since 2006. All studies but one were set in high-income countries, and more than half were in the USA.The majority of studies used predictive models to assess the effect of a proposed tax on consumption. Only 6 studies used observational data and 4 of these used data at the population rather than the individual level to look for associations between taxes and body weight.Nine studies assessed the effect of taxes on food consumption or expenditure alone, five on consumption and body weight, four on consumption and disease, and six on body weight only. Studies on soft drink taxes were the most common: there were 10 such studies, 2 of which also included "snack" taxes. Thereafter, 7 studies examined food taxation based on nutrient content, most commonly fat. Three studies assessed fruit and vegetable subsidies, and another assessed three taxes on a variety of "unhealthy" foods. Effect on consumptionPeer-reviewed studies The four peer-reviewed studies on food consumption all found that a subsidy, tax or change to a tax altered consumption in the expected direction. In an empirical study in Ireland, Bahl et al. 21 found that a 20% reduction in a soft drink tax resulted in a 6.8% increase in average soft drink consumption. However, had all of the tax reduction been passed on, consumption would actually have risen by 15%.Three studies modelled the effect of proposed taxation strategies on the whole diet. Smed et al. 24 examined seven scenarios for taxing unhealthy and subsidizing healthy foods and nutrients in Denmark. Each involved the equivalent of halving value added tax (VAT) on fruit and vegetables. They concluded that subsidizing specific nutrients was more effective than subsidizing food groups. Their best revenue-neutral scenario decreased average consumption of sugar by 6.5%, fat by 2.5% and saturated fat by 3.6%, and increased consumption of fibre by 6.5%.In a similar study, Jensen & Smed 22 found that younger consumers and loweri...