Five experiments demonstrate that the marketing of weight management drugs, but not supplements, undermines healthy lifestyle behaviors. Results suggest that drug marketing can affect behavior in both a mindful way, by undermining healthy behavioral intentions, or in a relatively mindless way, by increasing actual unhealthy consumption after mere exposure. Furthermore, two field studies suggest that erroneous consumer beliefs about drugs and supplements underlie this boomerang effect on consumer health, and only very high levels of expertise (e.g., medical training) are sufficient to eliminate it.

Health care practitioners, policy makers, researchers, and consumer groups alike have expressed concern over the recent rise in obesity rates in the United States. The National Center for Health Statistics (2002) has estimated a 3% annual compound rate of growth in the proportion of obese adults between 1991 and 2001. As of 2004, 32.9% of adults in the United States were obese, and 66.2% were obese or overweight (compared to 15% and 47% in 1980; Ogden et al.,2006).1 Increasing obesity rates are troubling in light of the associated health risks. For example, the Center for Disease Control has declared obesity a public health epidemic (Seiders & Petty, 2004), and obesity has been linked to increased risks for serious health conditions, such as hypertension, osteoarthritis, high cholesterol, diabetes, heart disease, stroke, gallbladder disease, sleep apnea, respiratory problems, and some cancers (e.g., Koplan, Liverman, & Kraak, 2005; National Center for Chronic Disease Prevention and Health Promotion, 2008; Sturm, 2002). Furthermore, it is estimated that obesity costs the U.S. health care system an additional $100 billion each year (Cleland et al., 2002), with health care costs increasing by 36% and medication costs by 77% (Fitch, Pyenson, Abbs, & Liang, 2004).