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[This corrects the article DOI: 10.3389/fnut.2022.967494.].
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Development agencies and international donors' efforts are increasingly focusing on better integrating poor and remote farmers into agricultural markets to address the chronic issues of rural poverty and hunger in low- and middle-income countries. Using systematic methods for information retrieval, critical appraisal and evidence synthesis, this research aims to examine evidence on the effects of five focal types of agricultural market access interventions: (i) farm-to-market transport infrastructure interventions; (ii) output market information interventions; (iii) initiatives creating new marketplaces and alternative marketing opportunities; (iv) contract farming initiatives; (v) interventions improving storage infrastructure. In this review, we will study evidence of the magnitude and direction of intervention effects on agricultural, socio-economic, and food and nutrition security outcomes. We will examine evidence of the distribution of reported effects across different contexts, interventions and sub-groups of the population (e.g., according to sex, socio-economic status, farm size, etc.). We will also report on included studies' risk of bias and on what evidence is available on intervention costs, or their cost-effectiveness. This protocol outlines this review's planned methods and the criteria for selecting and including studies in its analysis.
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Introduction: Both the World Health Organization and the Lancet Series on Adolescent nutrition recommend that governments adopt fiscal policies to combat diet-related non-communicable diseases (NCDs). However, rigorous, systematic evidence regarding the effects of these interventions is lacking. Methods: We synthesize the available evidence regarding the impacts of taxes and subsidies that directly affect consumer prices on availability and accessibility of foods and beverages, purchasing behavior, diet quality, health and well-being outcomes as well as considerations for implementation, sustainability and equity. Results: Our initial search returned 2,113 de-duplicated studies, and ultimately 24 impact evaluations and two systematic reviews met final eligibility criteria and represented unique evaluations. Our meta-analysis of these studies suggests that taxes may decrease purchases of taxed beverages (SMD = -0.14 [95% CI: -0.29 to -0.07], n = 15). Results should be interpreted cautiously due to considerable heterogeneity (Q(14) = 335.19, p = 0.01, τ ^ 2 = 0.03 , I 2 = 95.82%). Discussion: The evidence base is too limited to draw conclusions about the effects of taxes on beverages and calorie-dense foods on purchases, or on the effects of subsidies on purchasing or diet quality. Overall, the evidence base is inconclusive on whether fiscal policies can meaningfully influence the availability and accessibility of foods and beverages, diet quality, and health outcomes. Policymakers implementing fiscal policies should consider information campaigns on health benefits and health risks associated with certain food and beverage consumption. For taxes, exposure to health information may amplify signaling effects of taxes and reduce avoidance behaviors, such as cross-border shopping. Future evaluations should diversify data sources to better understand impacts on diet and health outcomes.