**3. Causal theories**

As our scientific understanding of the causes and consequences of obesity grows, it is especially important to track how the general public thinks about the condition. People have "lay theories" [8] about the causes and consequences of obesity that can differ markedly from the comparatively complex and nuanced scientific perspectives on obesity that have developed in recent years. For example, although public health officials have identified a range of complex social, physiological, and psychological factors that contribute to being obese [9], many people still think that individuals alone are responsible for maintaining a healthy weight [10, 11] (but see [12]). Such a disconnect represents an important obstacle for policy makers who seek to design and implement interventions that would address causes of obesity outside a person's control—since many people deny that obesity results from anything other than poor lifestyle decisions made at the individual level. In a democracy, public perceptions can be just as important for addressing complex issues as scientific theories and breakthroughs, since policy interventions are more likely to be accepted when they are consistent with the general public's

By investigating lay theories of obesity, therefore, researchers may gain a better understanding of why obesity rates are on the rise while at the same time they may be able to identify effective ways to address this public health crisis [15–17]. For example, it is important to know whether people think that self-regulatory behaviors such as diet and exercise can help maintain a healthy weight or whether people think that their weight is primarily determined by factors outside of their control. Several recent, but controversial, scientific studies have questioned the efficacy of diet and exercise for the prevention and treatment of obesity [18, 19]. This work has received substantial attention in the popular press, which is often distilled to pithy headlines such as, "Why you can't lose weight on a diet" [20]. How do people interpret these claims in light of what they know about obesity—and what do people know about obesity in the first place? Can messaging strategies be developed to promote support for the kinds of interventions that public health officials have argued will provide better treatments for obesity and reduce the prevalence of an issue that poses significant costs to individuals and society?

In this chapter, we develop an integrative review of the literature on lay theories of obesity, drawing on research in public health, communications, and psychology to illuminate the factors that shape beliefs and attitudes toward the condition, as well as the consequences of specific lay theories for cognition and behavior. We pay special attention to the role of narrative framing and individual demographics in the etiology of lay beliefs, and explore how particular psychological mechanisms (e.g., empathy) can affect how people think and reason about

People often think about obesity in the same way they think about other physical or psychological traits: as a basic attribute that individuals possess to varying degrees. Dweck et al. [21, 22] have identified two opposing lay theories that characterize how people think and reason about a variety of traits, which are distinguished by the degree to which the trait is viewed as

understanding of an issue such as obesity [13, 14].

24 Adiposity - Epidemiology and Treatment Modalities

obesity.

**2. Trait theories**

Another class of lay theories considers the causal origins of obesity, which may or may not have implications for beliefs about malleability. Research suggests that people often rely on narrative structures that include extended metaphors and analogies to think about complex issues like obesity [17, 24–27], and one recent study identified seven common narratives for obesity that capture different causal beliefs about the condition (see **Table 1**; [10]). Importantly, these narratives are also associated with different ways of thinking about how to address the problem of obesity—both at an individual and at a societal level [10, 16, 17].

A critical dimension that differentiates these lay causal theories is the degree to which they attribute personal responsibility or blame to obese individuals for being overweight. At one extreme is the view that individuals are entirely responsible for maintaining a healthy weight —the idea that addiction is a "sinful behavior." At the other extreme are views that suggest obesity is entirely the result of factors outside a person's control, such as a "toxic food environment" or "industry manipulation."

The idea that obesity is the result of "sinful behavior" evokes the biblical ban on sloth and gluttony [28] and places responsibility for maintaining a healthy weight squarely on the everyday decisions that individuals make about diet and exercise. Psychiatrist and media personality Keith Ablow embodies this perspective when he explains that obesity "is largely caused by poor decisions—like binging on food or eating lots of candy, ice cream or Cheetos" ([29], p. 1). On this view, rising rates of obesity are the result of more people making worse decisions about their health; addressing obesity, within this framework, is a challenge for individuals to eat healthier and exercise more.

Barry et al. [10] found that more than half of the participants in their survey of over 1000 people thought that "sinful behavior" was an important cause of obesity. Participants who endorsed this view tended to oppose policy interventions that public health officials argue would have a large impact on obesity [30]: by, for example, requiring restaurants and food producers to list nutritional information on menus and food packaging, to increase the availability of healthy food and opportunities for exercise, and to broaden the reach of laws designed to protect people with disabilities.

Participants identified which ones they thought provided an "important explanation" for why Americans are overweight. The narratives are ordered in terms of how much blame they ascribe to the individual: from highest to lowest.

**Table 1.** Seven narratives identified by Barry et al. [10] for explaining the obesity epidemic.

In a follow-up study, Thibodeau et al. [17] found that certain demographic characteristics of individuals are associated with thinking that being obese is blameworthy (i.e., to endorse the view that obesity is the result of "sinful behavior"; see [31] to get a sense for how these associations have and have not changed in the past few decades). Specifically, males, conservatives, and people who had a lower body mass index (BMI) or who had not personally suffered from an eating disorder were more likely to endorse the view that obesity is caused by poor decisions about diet and exercise (see also [32, 33], for related evidence that individuals with and without eating disorders have differing views of these conditions). This study replicated Barry et al.'s correlational finding [10]—showing that people who think obesity is blameworthy oppose societal-level interventions designed to prevent people from becoming overweight. In addition, Thibodeau et al. [17] found that these participants were more likely to support policy interventions that would increase individual accountability for maintaining a healthy weight (e.g., policies that would allow health insurers to charge higher premiums to people who are overweight). These results are illustrated in **Figure 1**.

Thibodeau et al. [17] also conducted an experiment to test whether reading a narrative about obesity could causally influence people's beliefs about the condition as well as their support for public policy interventions. Some participants read a narrative that emphasized personal accountability (using a variant of the "sinful behavior" account), while others read a narrative that highlighted factors outside a person's control (combining elements of the "industry manipulation" and "toxic food environment" themes) before being asked about their support for a variety of obesity-related public policies. The results suggested that describing obesity as blameworthy (sinful behavior) decreased support for protective policy interventions (i.e., interventions that would emphasize education, regulation of food-related advertising and manufacturing, and increase legal protections for obese individuals) and increased support for punitive actions (e.g., by allowing health insurers to charge higher premiums to obese individuals). On the other hand, people who were exposed to a narrative that deemphasized individual blameworthiness were less likely to support punitive actions. However, they were no more likely to support societal-level policy interventions. Instead, support for societal-level policy interventions was most strongly predicted by participants' political ideology: leftleaning, politically liberal participants tended to support societal-level policy interventions more than right-leaning, politically conservative individuals.

list nutritional information on menus and food packaging, to increase the availability of healthy food and opportunities for exercise, and to broaden the reach of laws designed to protect

**Narrative Theme Important**

on sugary, fatty foods, some cannot keep themselves from eating more and more

are treated badly even though their weight problems come from their parents

Participants identified which ones they thought provided an "important explanation" for why Americans are overweight. The narratives are ordered in terms of how much blame they ascribe to the individual: from highest to

Commercial interests dictate our choices and values. Advertising distorts how we

We are surrounded by choices that cheap but not good for us. Healthy foods are lost

In a follow-up study, Thibodeau et al. [17] found that certain demographic characteristics of individuals are associated with thinking that being obese is blameworthy (i.e., to endorse the view that obesity is the result of "sinful behavior"; see [31] to get a sense for how these associations have and have not changed in the past few decades). Specifically, males, conservatives, and people who had a lower body mass index (BMI) or who had not personally suffered from an eating disorder were more likely to endorse the view that obesity is caused by poor decisions about diet and exercise (see also [32, 33], for related evidence that individuals with and without eating disorders have differing views of these conditions). This study replicated Barry et al.'s correlational finding [10]—showing that people who think obesity is blameworthy oppose societal-level interventions designed to prevent people from becoming overweight. In addition, Thibodeau et al. [17] found that these participants were more likely to support policy interventions that would increase individual accountability for maintaining a healthy weight (e.g., policies that would allow health insurers to charge higher premiums to

Thibodeau et al. [17] also conducted an experiment to test whether reading a narrative about obesity could causally influence people's beliefs about the condition as well as their support

Sinful behavior People are unwilling to work hard to control their impulses. People who are

Addiction People get hooked on certain things and just cannot quit. When people get hooked

Time crunch Work has gotten in the way of important things. Obesity is a symptom of a society

Eating disorder Society sends the wrong messages about what it means to be attractive which leads people to go on fad diets that make them fatter

Disability We blame the victim for things they cannot control. People who are overweight

overweight are not even trying to get healthier

that emphasizes work at the expense of well-being

value food.  Seven narratives identified by Barry et al. [10] for explaining the obesity epidemic.

people who are overweight). These results are illustrated in **Figure 1**.

in a sea of unhealthy alternatives

**explanation**

50.5%

71.2%

58.0%

65.2%

51.3%

54.1%

77.5%

people with disabilities.

26 Adiposity - Epidemiology and Treatment Modalities

Industry manipulation

Toxic food environment

lowest.

**Figure 1.** Relationships between demographic characteristics, beliefs about the blameworthiness of obesity (as measured by participants' agreement with narratives for obesity that varied in how they attributed blame for being overweight), and support for different types of interventions designed to address rising rates of obesity found in a study by Thibodeau et al. [17]. Values reflect path coefficients in a structural equation model (\**p* < 0.05, \*\*\**p* < 0.001).

Together, this work suggests that there are several common narratives about the underlying causes of obesity and that these narratives provide a foundation for thinking about different ways of addressing the complex health issue. Specifically, the view that obesity is caused by a lack of personal motivation represents one common lay theory about obesity. The defining characteristic of this view is that it blames obese individuals for being overweight. This blame creates a stigma against obesity and represents a major obstacle to societal-level policy interventions that seek to address causes of obesity that are outside of a person's control (e.g., corporate manipulation and the availability of healthy food). Interestingly, this view can be further broken down into whether people believe it is a lack of exercise or an unhealthy diet that is the central causal factor in obesity, with predictable consequences for behavior: people who believe that lack of exercise plays a larger role in obesity than diet are more likely to consume more food and be overweight [11].

At the other end of the extreme, there are a variety of lay theories about the causes of obesity that blame factors outside of a person's control by highlighting a "toxic food environment" or "corporate manipulation" as culprits in the obesity crisis. Many participants in Barry et al.'s study [10] endorsed these narratives as capturing important causes of the obesity epidemic, and this judgment was correlated with support for more protective policy interventions. However, an experiment designed to test whether reading such narratives would increase support for the protective policy interventions failed to find support for a critical prediction: people who read a narrative that minimized the blame attributed to obese individuals for being overweight were no more likely to support societal-level policy interventions that would address causes of obesity outside a person's control [17]. Below, we discuss a popular alternative causal model of obesity—that it is a "disease"—which may be better suited to eliciting such support.