Communicating Evidence about the Causes of Obesity and Support for Obesity Policies: Two Population-Based Survey Experiments

Abstract

Public support for numerous obesity policies is low, which is one barrier to their implementation. One reason for this low support is the tendency to ascribe obesity to failings of willpower as opposed to the environment. Correlational evidence supports this position. However, the experimental evidence is mixed. In two experimental studies, participants were randomised to receive no message, messages about the environment’s influence on obesity (Study 1 & 2), or messages about the environment’s influence on human behaviour (Study 1). We investigated whether communicating these messages changed support for obesity policies and beliefs about the causes of obesity. Participants were recruited from nationally representative samples in Great Britain (Study 1 & 2) and the USA (Study 2) (total n = 4391). Study 2 was designed to replicate existing research. Neither study found evidence that communicating the messages increased support for obesity policies or strengthened beliefs about the environment’s role in obesity. Study 2, therefore, did not replicate two earlier experimental studies. Instead, the studies reported here suggest that people’s beliefs about the causes of obesity are resistant to change in response to evidence and are, therefore, not a promising avenue to increase support for obesity policies.

Monitoring changes in community support for policies on obesity prevention

“…Several studies have shown greater support for government policies is associated with an understanding that overweight is caused by the food environment and is outside the individual's control. 39,40 Reynolds et al (2020) has recently challenged these results, finding no change in support for policies when the environmental causes of obesity were communicated, 41 concluding in a metaanalysis that the different results could be due to insufficiently persuasive messages. 42 The 'nanny state' narrative by the food industry or in media may also be another contributor to how the public perceives regulatory measures.…”

Communicating evidence about the environment’s role in obesity and support for government policies to tackle obesity: a systematic review with meta-analysis

“…Although the interventions mostly differed across studies, there are two principle reasons why intervention content is unlikely to fully account for these discrepant results. First, interventions sourced from these two studies were used in a third study that did not replicate the results (Reynolds, Vasiljevic, et al, 2020 ). Second, the intervention messages across all studies contained largely overlapping information.…”

“…While correlational evidence supports this approach, the experimental evidence provides mixed support. Several studies appear to suggest that communicating evidence of the environment’s influence on obesity has no effect on support for obesity policies (McGlynn & McGlone, 2018 ; Reynolds, Vasiljevic, et al, 2020 ; Young et al, 2016 ). Other studies report some statistically significant effects (Ortiz et al, 2016 ; Pearl & Lebowitz, 2014 ), but sometimes just in one subgroup (Garbarino et al, 2018 ).…”

“…Other studies report some statistically significant effects (Ortiz et al, 2016 ; Pearl & Lebowitz, 2014 ), but sometimes just in one subgroup (Garbarino et al, 2018 ). While these studies differ somewhat in the messages that they communicated to participants, this seems unlikely to account for these mixed effects given that first, there is a large amount of overlap in message content and second, there are conflicting results between studies using the same messages (Ortiz et al, 2016 ; Pearl & Lebowitz, 2014 ; Reynolds, Vasiljevic, et al, 2020 ). This warrants a systematic synthesis of the extant literature.…”

“…Changing beliefs about the other influences on obesity – such as attempting to weaken the belief that a lack willpower influences obesity – may be irrelevant. This is due to correlational analyses which show that attributing obesity to willpower, or even to genetics, has negligible or small positive associations with support for policies that aim to reduce obesity (Beeken & Wardle, 2013 ; Petrescu et al, 2016 ; Reynolds et al, 2018 ; Reynolds, Vasiljevic, et al, 2020 ). The hypothesis implicit in many of these studies is that any meaningful increase in support follows strengthening the belief that environmental cues influence obesity regardless of changes in beliefs about the role of willpower or genetics.…”