Overweight and obesity have increased dramatically worldwide and in the United States over the past 30 years among both adults and children (Adderley-Kelly, 2007, Hedley et al., 2004, Huang et al., 2003 and Mokdad et al., 2001), and concern is growing that sugar-sweetened beverage (SSB) consumption may contribute to increasing obesity rates (Huffman & West, 2007). Frary, Johnson, & Wang (2004) reported that patterns of beverage consumption are associated with adolescent obesity and overweight and those unhealthy beverages (e.g., sugar-sweetened or soft drinks) have a negative impact on adolescent diet quality. Furthermore, a randomized controlled study reported that SSB consumption might promote obesity and that reducing consumption would benefit body weight (Ebbeling et al., 2006). A self-report survey about sugared beverages indicated that SSB consumption among undergraduates is substantial and probably contributes considerable non-nutritive calories, which may contribute to weight gain (West et al., 2006). Hence, interventions targeting excess SSB intake may have an important role in obesity-prevention efforts for college-aged populations (Huffman & West, 2007). Given that healthy or unhealthy beverage consumption is a crucial factor in college student obesity and overweight, research on how to decrease unhealthy beverage purchases is important.
Most studies of obesity or unhealthy food and beverage consumption have focused on demographic (DeBate et al., 2001, Huffman and West, 2007 and West et al., 2006), biological (Lee et al., 2007 and Talpade, 2006), psychological (Newell et al., 1990 and Stevenson et al., 2007), behavioral (Kremers et al., 2007 and Rao, 2006), and socio-cultural (Klaczynski et al., 2004 and Wichrama et al., 2006) correlates. Few studies have examined effects of the interplay of price and purchase on unhealthy beverage consumption. Obesity is due, in part, to excess intake of energy-dense, nutrient-poor foods and a sedentary lifestyle (Epstein, Roemmich, & Raynor, 2001). Interventions to treat or prevent obesity must shift food choices from energy-dense foods to healthier low-fat, nutrient-dense alternatives. One way to encourage such shifts is to limit access to unhealthy foods (Goldfield and Epstein, 2002 and Smith and Epstein, 1991). According to behavioral-economic findings, one approach is to vary the cost of alternative commodities (Dufwenberg, 2007, Harrison, 2005 and Rachlin, 1989). For example, consumption of less-healthy foods can be reduced by taxing high-fat, low-nutrient snack foods (Jacobson & Brownell, 2000), whereas consumption of healthy alternatives can be increased by reducing the price of healthier, low-fat snack foods in vending machines (French et al., 1997) and the prices of fruits, vegetables, and low-fat foods in cafeterias (Cinciripini, 1984 and Jeffery et al., 1994).
Based on a behavioral-economics perspective, increasing the price of a commodity should reduce its consumption, a phenomenon termed “same-price elasticity” (Bickel, Madden, & Petry, 1998). However, increasing the price of one commodity may also increase consumption of a substitute commodity, a phenomenon called “cross-price elasticity.” The present study tested the relationship between changes in price and purchases of beverages in a laboratory setting. Previous research suggests that college students will be less likely to choose unhealthy (or healthy) beverages as their price increases. Moreover, college students will be more likely choose healthier beverages when the price of less-healthy beverages increases, despite a preference for unhealthy beverages.
Previous studies have suggested that consumer health concerns are closely related to dietary consumption (e.g., Ares et al., 2009, Kähkönen et al., 1999 and Sun, 2008). Recent years have seen a significant increase in concerns about health and wellness and a corresponding growth in consumer demand for healthy food products (Glazer, 2008). For example, consumers in the United States are turning to food and beverages to help address specific health concerns (Landi, 2007). Moreover, consumer health concerns are influenced by health claims (e.g., Silvergrade, 1991 and Wansink et al., 2004). Therefore, we predicted that health concerns evoked by health claims would induce substitution of healthy for unhealthy beverages. Health claims regarding beverage consumption may facilitate the effect of cross-price elasticity on purchases of healthy beverages. Following this logic, it was also predicted that health claims may weaken the effects of increasing prices for healthy beverages (i.e., the same-price-elasticity effect).
