The "Calories-Must-Be-Bad" Bias: How the Belief that Calories are Unhealthy Increases the Choice Share of Less Nutritious Options

Faced with a widespread problem of obesity, public health programs have long warned consumers to mind their calorie intake, with mixed results (Long et al. 2015; Parker and Lehmann 2014; Shah et al. 2014). We argue that the incessant negative attention to calories has led to an unjustified belief that "calories must be bad" that biases judgments of perceived nutritional value of relatively more (versus less) nutritious products, as well as consumers' choices of snacks. As calories are believed to be bad, they are psychologically strongly associated with less nutritious products, while in reality more nutritious products often contain as many or more calories (e.g., walnuts and olive oil are more calorie-dense than potato chips and butter, respectively). We propose that this bias can harm long-standing efforts to improve people's diet (Mozaffarian 2016). Study 1 aimed to establish market evidence that in several categories of snacks, more nutritious options have as many calories as less nutritious counterparts. We recorded the nutritional content of the top 20 bestsellers in three more nutritious categories (granola bars, nuts & seeds, trail snack & mixes) and three less nutritious categories (cookies, potato chips, candies & chocolate) based on the ranking of a large online retailer (i.e., Amazon). Two pretests found that "granola bars", "nuts & seeds", and "trail snack & mixes" are perceived as good substitutes for and as more nutritious than "cookies", "potato chips", and "candies & chocolate" respectively. We found that products in the more nutritious categories and those in the less nutritious categories do not differ in caloric content, F(1, 111) = 1.20, p =.28. However, more nutritious snacks have more proteins, p