摘要：Objectives. We quantified the use of placement and price reduction marketing strategies in different food retail outlets to identify associations between these strategies and the risk of overweight and obesity among customers. Methods. In 2011 we collected dietary and health information from 1372 residents in “food deserts” in Pittsburgh, PA. We audited neighborhood restaurants and food stores (n = 40) including 16 distant food venues at which residents reported shopping. We assessed end-aisle displays, special floor displays, cash register displays, and price reductions for sugar-sweetened beverages (SSBs); foods high in saturated oils, fats, and added sugars; and nutritious foods such as fruits, vegetables, and products with at least 51% whole grains. Results. Supermarkets and superstores had the largest numbers of displays and price reductions for low-nutrient foods. Exposure to displays of SSBs and foods high in saturated oils, fats, and added sugars and price reduction of SSBs was associated with increased body mass index. Conclusions. In-store marketing strategies of low-nutrient foods appear to be risk factors for a higher body mass index among regular shoppers. Future research is needed to confirm the causal role of marketing strategies in obesity. Although environmental health research has examined the consequences of a wide variety of ambient exposures on human health, there are limited efforts to quantify the impact of human exposure to in-store marketing strategies. Business practices do not fit neatly within the realm of what environmental health usually focuses on: pollutants, tobacco smoke, sanitary practices, and conditions that lead to physical injuries. Yet if an exposure to some external factor increases the risk of a negative health outcome, especially a factor that a person cannot easily avoid or control at the individual level, it should be considered fair game for the field of environmental health. Although many laud supermarkets as vital in addressing obesity because of the large variety of fresh fruits and vegetables available, 1–3 supermarkets also stock large quantities of low-nutrient foods that contribute to unnecessary weight gain. Historically, research in the 1970s suggested that increasing shelf space and placement of goods in prominent locations were key factors in increasing their sales. 4–7 A recent study investigated the promotional strategy of merely placing different beverages on end-of-aisle displays and found that such placement increased sales of carbonated drinks by 51.7% ( P < .001), an effect size equivalent to a price reduction of 22%. 8 Finding that store factors were more important than individual factors in influencing what people purchased 4–7 led to a dramatic acceleration in the use of “slotting contracts” in the early 1980s, a practice whereby manufacturers paid retailers to display their goods in specific spaces in the store. 9 However, the main concern about these practices was not how they manipulated consumers or influenced the American diet, but whether such practices constituted unfair competition for small manufacturers who could not afford to pay for the space. 9 It may be no coincidence that between 1980 and 2000, while the food industry learned how to sell larger quantities of low-nutrient processed foods merely by manipulating their placement, 10,11 rates of obesity in the United States doubled. 12,13 To capitalize on the sales boost from placing goods at the cash register, the end aisles, or on special floor displays 4,6,8,14 over the past few decades, the size of supermarkets expanded to supply more shelf space, especially more of the valuable end-aisle facings that could be leased to vendors. 9 Today, an estimated 30% of all supermarket sales can be attributed to end-aisle displays. 14 If food marketing efforts had no impact on people’s dietary behaviors, we would see no correlation between these efforts and health outcomes. Yet associations between food marketing efforts and food shopping behaviors and dietary outcomes could indicate that (1) the marketing influenced people’s dietary choices, (2) marketing is strategically responsive to people’s dietary choices, or (3) the relationship is a proxy for other unrecognized factors. The extent to which marketing may interfere with individuals’ long-term goals has not been quantified. Although popular perspectives on obesity, espoused by the US House of Representatives through the Personal Responsibility of Food Consumption Act, 15 that the full responsibility falls on individuals to limit what they purchase and what they consume, there is strong evidence that people are influenced by marketing tactics in ways they cannot easily recognize or resist. 16 Moreover, many marketing efforts are not always perceived as such, often resulting in consumers being influenced outside of awareness. 17 For example, few people would recognize that the physical location of an item in a store would increase their odds of buying it. 14,18 In this case, individuals may have less ability to counter the influence of this “hidden” marketing. The second explanation, that marketers are responsive to people’s diets, is also likely to be true. Knowing that individuals like sweets 19 and foods high in fats and salt, many companies develop novel products to suit these innate preferences. 20 Yet if people desired these foods in and of themselves, no special promotional efforts might be necessary, as individuals would seek them out, regardless of how they were presented. Nevertheless, many companies find it highly worthwhile to spend the extra money to underwrite marketing strategies that increase product salience and accessibility, 11 thus making the claim that marketers are merely being responsive less plausible. Bruyneel et al. and Wang et al. have shown that shopping is a cognitively depleting activity, explaining why, at the end of the trip, people become more vulnerable to displays at the cash register. 21,22 Mullainathan and Shafir have suggested that persons with limited incomes are particularly vulnerable to price reductions and other impulse marketing strategies, because of a preoccupation with limited funds. 23 When the mental demands of decision-making are overwhelming, the capacity for self-control is significantly diminished. 24 However, the evidence that a particular promotion actually affects the routine diets of individuals is lacking, as individuals may buy promoted items, but not consume them right away, stockpile them and consume them slowly over time. 25 Or they may buy them for individuals other than themselves. It behooves researchers to investigate whether in-store factors should be considered risk factors for poor health. To see whether there is evidence of a dose–response relationship between common in-store marketing strategies, dietary outcomes, and body mass index (BMI; a measure of overweight and obesity defined as weight in kilograms divided by the square of height in meters [kg/m2]) we sampled a population of low-income individuals and the food stores at which they shopped in the past month.
