**4. Disease theories**

In recent years, doctors and public health officials have sought to reduce the stigma of obesity and increase support for obesity-related research and policy interventions by officially classifying obesity as a "disease" [34–36]. Like narratives that highlight the role of environmental factors in obesity (e.g., "toxic food environment," "corporate manipulation"), describing obesity as a "disease" seems to reduce the personal responsibility associated with the condition. However, rather than appealing to external factors—the social and physical environments in which people live—thinking of obesity as a "disease" makes the condition less blameworthy by appealing to underlying physiological factors as the primary causes of weight gain [36].

Recent research suggests that this biomedical view of obesity has gone from a minority viewpoint just three decades ago to perhaps *the* dominant perspective today [37] (but see [11]). This shift represents an important achievement for public health communications. At a high level, the increased public recognition of obesity as a "disease" in recent years suggests that the way health officials talk about obesity has significant downstream effects on how the general public thinks about the condition. At a more practical level, one of the specific goals of the messaging campaign seems to have been achieved, as a majority of the US population recently reported that thinking of obesity as a disease would facilitate treatment of the condition [37].

However, researchers have also identified drawbacks to the disease model of obesity. The belief that weight is somewhat fixed by biological factors may negatively impact dieting goals and exercise intentions, especially among people who are overweight [15, 38]. In other words, reducing the blameworthiness of being obese is a double-edged sword: it not only mitigates the stigma associated with being overweight but also fosters an entity theory of obesity, reducing an important source of motivation for maintaining healthy habits that can help people lose weight (or gain it in the first place). In one study, for example, overweight participants who read a *New York Times* article describing obesity as a disease displayed lower body-image dissatisfaction compared to those who read an article arguing against the disease construal, but they also expressed less concern for healthy dieting and were more like to make unhealthy food choices when given the chance [15].

There are, certainly, many different types of diseases, and thinking about obesity in terms of one particular type of disease or another may have unique consequences for reasoning and behavior. For instance, conceptualizing obesity as a genetic disorder (i.e., caused by an underlying genetic predisposition) seems to be especially associated with the belief that people have no control over their weight [38]. In comparison to those who read a report that provided a psychosocial explanation for obesity, one study found that people exposed to a genetic explanation for the condition ate more cookies in a follow-up task [38]. On the other hand, conceptualizing obesity as a form of addiction disorder seems to have more inconsistent effects on eating behavior. One experiment revealed that while reading a message stating that food addiction is "real" (as opposed to a "myth") *does* lead people to be more likely to self-identify as a "food addict," these individuals did not consume a greater quantity of indulgent food in a subsequent "taste-test" task (though they did eat a wider variety of items [39]). However, another study found that participants who were told they had high food addiction tendencies (as opposed to low food addiction tendencies) consumed *fewer* calories in a follow-up taste test, a result which was mediated by increased concern for their diet [40].

Taken together, these findings help reveal the nuances underlying the "disease" model of obesity, and the complex, sometimes negative, consequences of messaging campaigns that tap into this way of framing the issue. Recent research suggests that some of the limitations associated with standard messaging strategies may be addressed by exposing people to personal testimonials that describe successful weight loss (rather than basic causal explanations [41, 42]). We discuss this work in the following section, which also hints at a psychological mechanism—empathy—that can be leveraged to increase support for societal-level obesity policy interventions.
