Which Healthy Eating Nudges Work Best? A Meta-Analysis of Field Experiments

• Main Authors: Cadario, Romain, Chandon, Pierre
• Format: Conference Proceeding
• Language: English
• Subjects: Eating behavior; Meta-analysis
• ISSN: 0098-9258

Healthy eating nudges have generated a lot of excitement but, disappointingly, existing meta-analyses have only found average fect ranging from null to moderate. Our work contributes to the many useful existing meta-analyses in terms of (1) scale and scope, (2) method, and (3) categorization of predictors. In terms of scale and scope, we examine more than twice as many effect sizes as the largest existing meta-analysis. This is achieved despite focusing only on field experiments involving actual food choices (vs. perception, evaluation, or choice intentions) and conducted in field settings (onsite cafeterias, offsite eateries, or grocery stores) rather than in a laboratory or online. This allows us to offer guidance to restaurants, supermarket chains, and foodservice companies who want to help their customers eat more healthily but do not know which intervention will work best in their particular context; and to provide guidance for policy makers who need to forecast the effects that these nudges would have in real-world settings. Methodologically, our meta-analysis differs from earlier ones on three levels. First, we formulate hypotheses about which healthy eating nudges work best and about the effects of eating behavior and of population and study factors. Second, to reduce the risk of confounds from univariate analyses, we employ a multivariate model incorporating all predictors simultaneously. Third, we include a three-level analysis to take into account the hierarchical structure of our data. Finally, Figure 1 shows that we use a more granular predictor structure compared to existing meta-analyses, which either estimated the effect size of a single type of healthy eating nudge or compared the effect of one single difference (say, descriptive vs. evaluative labeling) and which rarely incorporated behavior, population, and study characteristics. We distinguish between seven nudge interventions classified according to whether they are 1) cognitively-oriented, such as descriptive nutritional labeling, evaluative nutritional labeling, or visibility enhancements; 2) affectively-oriented, such as hedonic enhancements or healthy eating calls; or 3) behaviorally-oriented, such as convenience enhancements or size enhancements. Our framework also accounts for the type of eating behavior (food selection or consumption) and distinguishes between healthy eating, unhealthy eating, and total energy intake. It also considers population characteristics such as age (chi