摘要：In light of proposals to improve diets by shifting food prices, it is important to understand how price changes affect demand for various foods. We reviewed 160 studies on the price elasticity of demand for major food categories to assess mean elasticities by food category and variations in estimates by study design. Price elasticities for foods and nonalcoholic beverages ranged from 0.27 to 0.81 (absolute values), with food away from home, soft drinks, juice, and meats being most responsive to price changes (0.7–0.8). As an example, a 10% increase in soft drink prices should reduce consumption by 8% to 10%. Studies estimating price effects on substitutions from unhealthy to healthy food and price responsiveness among at-risk populations are particularly needed. THE INCREASING BURDEN OF diet-related chronic diseases has prompted policymakers and researchers to explore broad-based approaches to improving diets. 1 , 2 One way to address the issue is to change the relative prices of selected foods through carefully designed tax or subsidy policies. The potential of price changes to improve food choices is evident from growing research on how relative food prices affect dietary quality and obesity, particularly among young people, lower income populations, and those most at risk for obesity. 3 Experience from tobacco tax regulation further underscores the power of price changes to influence purchasing behavior and, ultimately, public health. 4 Experimental research in both laboratory and intervention settings shows that lowering the price of healthier foods and raising the price of less healthy alternatives shift purchases toward healthier food options. 5 – 8 Although these studies demonstrate price effects in specific, isolated settings or on 1 or 2 individual product changes, to our knowledge, the expected effects of broader food price changes have not been systematically reviewed. Such information would be helpful in designing policies that change the relative food and beverage prices paid by all or many consumers. Relatively small-scale, cost-neutral approaches to improving nutrition in vulnerable populations include the 2009 changes in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) food packages; whole grains, fruits and vegetables, and soy-based milk alternatives were added to these packages, indirectly subsidizing healthy foods for WIC participants. 9 Another larger scale approach is to change prices directly through taxing products such as sugar-sweetened beverages 1 , 10 or subsidizing healthier foods (e.g., a refund on the costs of fruits and vegetables to Supplemental Nutrition Assistance Program participants). 11 Some states already tax soft drinks and snacks at higher rates than other foods, but thus far taxes have been small and designed to generate revenue rather than influence consumption. 12 We sought to estimate the effects of price changes on consumer demand for major commodity foods included in the Dietary Guidelines for Americans food categories. 13 We identified all published US studies of food price elasticity of demand (the expected proportional change in product demand for a given percentage change in price) and combined their estimates into average estimated price elasticities for 16 major food and beverage groups. Our goal was to provide a comprehensive summary of research on food demand and consumption behavior in the United States over the past 7 decades, with particular attention to differences in price effects across income levels. One timely estimate that can be gained from our review is how altering the prices of soft drinks can alter their consumption, information that is of critical need for policymakers considering soft drink taxes. We compared the sensitivity of estimates across different analytic approaches to modeling food demand. We identify important gaps in the food demand analysis literature and suggest avenues for future research.
