Nudging healthier food choices in a cafeteria setting: A sequential multi-intervention field study

Together towards sustainable dining - Cocreating behavioral change interventions with restaurants

Behavioral change interventions in restaurants towards sustainable food choices are a promising avenue towards attaining climate goals. In this research, we investigated how these interventions can successfully be implemented in a restaurant context to promote sustainable food choices. In a multiple-year co-creation project with 32 restaurants and consultant chefs, we provided knowledge on sustainable meal preparation and on using behavioral interventions, collaborated to design suitable interventions for the individual restaurants, and tested these interventions in a mixed methods approach. We provided support from researchers and consultant chefs throughout this process. The four restaurants that ultimately implemented an intervention were all successful in increasing uptake of their sustainable menu options. While participants' overall support and enthusiasm for knowledge of sustainability interventions was high, especially towards more sustainable meal preparation, many restaurants dropped out of the project. Despite using a time- and resource-intensive approach, it remained difficult to overcome both psychological barriers (no perceived responsibility and the sense of already "doing enough") as well as practical hurdles (fear of customers' response and lack of time) for restaurants. As implementation of the co-created solutions proved very challenging, future research on interventions promoting sustainable food choices should therefore specifically focus on taking away practical barriers. Possible avenues for doing so are focusing on more sustainable meal preparation, involving customers in cocreation, and a greater focus on the responsibility of the sector in culinary and hospitality education to instill sustainable habits there, which are then more easily practiced when working in the field.

"Just-in-time" but a bit delayed: Personalizing digital nudges for healthier online food choices

As food choices are increasingly made in contexts such as online supermarkets, nudging has been extrapolated to the digital sphere. Digitalization poses unique opportunities to enhance the promotion of healthier food choices online: Digital nudges can be delivered "just-in-time" (JIT), in response to the initial selection of an unhealthy product. Furthermore, digital JIT nudges can be personalized to match user characteristics of behavioral relevance, such as one's food and cognitive processing preferences. We examined whether personalizing by user-matching digital JIT nudges on content (i.e., emphasizing health versus price) and/or type (i.e., a text-based versus an image-based nudge) would increase nudge effectiveness and healthier food purchases, and assessed psychological mechanisms potentially underlying these enhanced effects. In a 2 (Nudge Content: Non-personalized versus Personalized) by 2 (Nudge Type: Non-personalized versus Personalized) randomized controlled trial, 200 healthy participants completed an online grocery shopping task on a mock supermarket app in which they first selected products from 10 different categories, followed by a checkout screen where they could replace products in the shopping basket. Personalizing nudge type increased nudge effectiveness (i.e., the proportion of accepted nudges when choosing products from categories). Personalizing nudge content seemed to exert a delayed effect of increasing healthier product replacements prior to checkout. User perceptions of JIT nudges did not vary with personalization. However, regardless of personalization, all JIT nudging conditions had more final healthier food purchases and greater satisfaction with food choices compared to the control condition. Collectively, this pre-registered "proof-of-principle" study demonstrates that personalizing the content and type of digital JIT nudges yields small positive benefits on the healthiness of online food choices and attests to the utility of JIT interventions for health promotion.

Bundled measures for China's food system transformation reveal social and environmental co-benefits

Food systems are essential for the achievement of the United Nations Sustainable Development Goals in China. Here, using an integrated assessment modelling framework that considers country-specific pathways and covers 18 indicators, we find that most social and environmental targets for the Chinese food system under current trends are not aligned with the United Nations Agenda 2030. We further quantify the impacts of multiple measures, revealing potential trade-offs in pursuing strategies aimed at public health, environmental sustainability and livelihood improvement in isolation. Among the individual packages of measures, a shift towards healthy diets exhibits the lowest level of trade-offs, leading to improvements in nutrition, health, environment and livelihoods. In contrast, focusing efforts on climate change mitigation and ecological conservation, or promoting faster socioeconomic development alone, have trade-offs between social and environmental outcomes. These trade-offs could be minimized by bundling all three aspects of measures.

Using salience and availability to promote sustainable and healthy food choices in hospital cafeterias

Sustainable diets can achieve considerable reductions in greenhouse gas emissions and improvements in human health, but changing dietary behavior remains a challenge. We assessed the impacts of two behavioral insights strategies on bridging the intention-action gap related to sustainable and healthy food choices amongst hospital cafeteria patrons. In a pilot survey of hospital staff (N = 1,165), 56% identified limited awareness and availability of sustainable food as barriers to purchasing, although 46% were extremely willing to try sustainable dishes. We examined increasing salience (Study 1), varying availability (Study 2a), and decreasing availability (Study 2b) on sustainable and healthy dish purchases in three hospital cafeterias. Each study ran for seven weeks from March to April, 2023. In total, 10,616 dishes were purchased. In Study 1, increasing salience was associated with significant uptake of sustainable and healthy dishes, but the effect disappeared once the salience intervention was removed. In Study 2a, increasing availability of sustainable dishes corresponded to a significant increase in purchases of sustainable dishes, while decreasing availability in Study 2b followed a downward trend in purchases, suggesting that availability drove dietary choices. We recommend hospitals consider these choice architecture interventions to support the adoption of sustainable and healthy diets.

We meat again: a field study on the moderating role of location-specific consumer preferences in nudging vegetarian options

This field study set out to test whether consumers' history of making decisions in a particular choice context moderated the effectiveness of a nudge intervention to reduce meat consumption. In a Danish hospital canteen that served both staff members and visitors, a combination of nudges (Chef's recommendation sticker + prominent positioning) was implemented to promote vegetarian sandwiches. The sales of these sandwiches increased from 16.45% during the baseline period to 25.16% during the nudge intervention period. Most notably, this increase was caused by the visitors, who had weak location-bound preferences. Hospital staff members (who had strong location-bound preferences) were unaffected by the nudge in their choice. This is an important finding because the two consumer groups did not differ on their person-bound preferences for meat. It seems that behaviour change is best predicted by location-bound preferences, whereas the behaviour itself is best predicted by person-bound preferences. These findings can help organizations in estimating whether a nudge intervention has enough potential for behaviour change, or whether more directive policies are required.

Nudging towards sustainable dining: Exploring menu nudges to promote vegetarian meal choices in restaurants

Food choice behavior plays a large role in achieving sustainability goals. Meat in particular has a negative environmental impact as compared with plant-based food - and is more frequently chosen in restaurant contexts. To increase plant-based meal choices in restaurants, we tested three nudges for menus that are likely to be implemented by restaurant owners: a hedonic label (e.g., artisanal vegetable burger), a chef's recommendation (specifying the vegetarian option as the chef's favorite), and a salience nudge (a box around the vegetarian option). In an online experiment, we showed participants (n = 513) in four conditions (no nudge, hedonic label, chef's recommendation, and salience nudge) five menus with four meal options each, one of which was vegetarian. We asked participants to choose a meal and subsequently to rate these meals on how tasty and indulgent they were (taste and indulgence attributions). We then revealed which nudge was used to the participants and asked how participants received it. Results show that the hedonic label and chef's recommendation nudge (but not the salience nudge) both increase vegetarian meal choices. The hedonic label increased participants' attributions of indulgence of the meal, but not of tastiness. This finding fits with restaurants' gastronomic, pleasure-seeking context and shapes future directions of labeling interventions, namely that indulgence attributions can be increased in vegetarian foods. Furthermore, the nudges were generally well accepted and participants' intention to return to the (virtual) restaurant was high. Finally, customers expected the hedonic label nudge to be more effective in promoting vegetarian food choices than the other two nudges, partially corresponding with our findings of actual effectiveness.

Every step you take: Nudging animal welfare product purchases in a virtual supermarket

Animal welfare (AW) is a growing concern for consumers in Germany; however, not all consumers regularly purchase products that have been produced according to high AW standards. The goal of the present study is to test the effect of a multilayered nudge to increase the availability and improve the visibility of AW products in a 3D online virtual supermarket (VS). The nudge included a shelf with AW products (referred to as AW shelf) which was made visible through banners and footsteps on the floor of the VS. The sample of this pre-registered experiment consisted of n = 374 German consumers who regularly purchase meat, milk, and eggs. The results demonstrated that the multilayered nudge was highly effective: the percentage of AW products purchased in the nudging condition was almost twice as high as in the control group. Furthermore, we investigated variables that mediate (ease of finding AW products in the VS) and moderate (price sensitivity) the effectiveness of the multilayered nudge, but no evidence for an effect was obtained. We conclude that multilayered nudges may be a promising tool to increase consumers' AW product purchases. More research is needed to replicate this finding with a field study in a real supermarket.

When and Why Do People Accept Public-Policy Interventions? An Integrative Public-Policy-Acceptance Framework

The successful introduction of public policies to prompt behavior change hinges on the degree to which citizens endorse the proposed policies. Although there is a large body of research on psychological determinants of public policy acceptance, these determinants have not yet been synthesized into an integrative framework that proposes hypotheses about their interplay. In this article, we develop a review-based, integrative public-policy-acceptance framework that introduces the desire for governmental support as a motivational foundation in public-policy acceptance. The framework traces the route from problem awareness to policy acceptance and, ultimately, policy compliance. We propose this relationship to be mediated by a desire for governmental support. We integrate numerous key variables assumed to qualify the relationship between problem awareness and the desire for governmental support, such as control attributions, trust, and value fit, as well as the relationship between the desire for governmental support and policy acceptance, such as perceived policy effectiveness, intrusiveness, and fairness. We exemplify the use of the proposed framework by applying it to climate policies.

Effects of a Nudging Cue Targeting Food Choice in a University Cafeteria: A Field Study

Many students approaching adulthood often choose high-calorie food products. Concurrently, health interventions applied during this life phase can potentially lead to a healthier lifestyle. Nudge health interventions in experimental cafeteria settings have been found to improve eating behavior effectively, yet research in real-world settings is lacking. Accepting nudges as health interventions impacts nudge effectiveness. The present study applies a pretest-posttest design for a period of three consecutive weeks (no nudge, nudge, no nudge), testing the effectiveness of the so-called Giacometti cue on the number of calories purchased in a real-world cafeteria. Students were exposed to the nudge during the intervention week when entering the cafeteria and when choosing their meals. After purchasing a meal, their choice was recorded, and they completed a questionnaire. The Giacometti cue immediately reduced the number of calories purchased (comparing weeks one and two). After nudge removal, an effect was identified, increasing the number of calories purchased (comparing weeks two and three). Contrary to expectations, higher nudge acceptance resulted in more calories purchased. Neither awareness of the nudge's presence when buying food nor the interaction between acceptance and awareness played a role. We explore potential explanations for the Giacometti cue's effects.

A Bibliometric Analysis and Review of Nudge Research Using VOSviewer

With growing demands of decision making in the current era, the impact of the drivers behind individuals' preferences and institutional strategies becomes prominent. Coined in 2008, nudge is used to describe incentives for individuals' choices with foreseeable outcomes but without exclusion of alternative choices or reliance on financial stimuli. Consequently, nudge and its application in real-world situations led to a prosperous surge of studies in multiple disciplines. However, we are still facing a dearth of in-depth understanding of the status quo and future directions of research on nudge in a comprehensive fashion. To address the gap in knowledge, the present study adopted a bibliometric analysis of the existing literature related to the investigation and application of nudge by analyzing 1706 publications retrieved from Web of Science. The results indicated that (a) being a relatively newly developed theory, interest in nudge in academia has expanded both in volume and disciplines, with Western scholars and behavioral economists as the backbones; (b) future studies in nudge-related fields are expected to consolidate its current frontiers in individual behaviors while shedding light on new territories such as the digitalized environment. By incorporating state-of-the-art technologies to investigate extant research, the present study would be pivotal for the holistic understanding of the studies on nudge in recent years. Nevertheless, the inclusiveness and comprehensiveness of the review were limited by the size of the selected literature.

Sensory Appeal and Routines Beat Health Messages and Visibility Enhancements: Mixed-Methods Analysis of a Choice-Architecture Intervention in a Workplace Cafeteria

Easier recognition and enhanced visibility of healthy options supposedly increase healthy choices, but real-world evidence remains scarce. Addressing this knowledge gap, we promoted nutritionally favourable foods in a workplace cafeteria with three choice-architectural strategies-priming posters, point-of-choice nutrition labels, and improved product placement-and assessed their effects on visual attention, food choices, and food consumption. Additionally, we developed a method for analysing real-world eye-tracking data. The study followed a pretest-posttest design whereby control and intervention condition lasted five days each. We monitored visual attention (i.e., total number and duration of fixations) and food choices with eye tracking, interviewed customers about perceived influences on food choices, and measured cafeteria-level food consumption (g). Individual-level data represents 22 control and 19 intervention participants recruited at the cafeteria entrance. Cafeteria-level data represents food consumption during the trial (556/589 meals sold). Results indicated that the posters and labels captured participants' visual attention (~13% of fixations on defined areas of interest before food choices), but the intervention had insignificant effects on visual attention to foods, on food choices, and on food consumption. Interviews revealed 17 perceived influences on food choices, the most common being sensory appeal, healthiness, and familiarity. To conclude, the intervention appeared capable of attracting visual attention, yet ineffective in increasing healthier eating. The developed method enabled a rigorous analysis of visual attention and food choices in a natural choice setting. We discuss ways to boost the impact of the intervention on behaviour, considering target groups' motives. The work contributes with a unique, mixed-methods approach and a real-world setting that enabled a multi-dimensional effects evaluation with high external validity.

Measuring “Nudgeability”: Development of a Scale on Susceptibility to Physical Activity Nudges among College Students

Background: The current college lifestyle create more opportunities for students to develop unhealthy behaviors, especially physical inactivity. Nudging could be an effective tool to improve physical activity behaviors by changing college settings. One-nudge-fits-all leads to ineffective nudges, so it is necessary to develop a reliable and valid instrument capable of measuring the “nudgeability” of physical activity nudges for college students, which is for a higher level of nudge efficacy. Method: Developing the College Physical Activity Nudges Susceptibility Scale (CPANSS) that integrated the nudge method with the Likert scale, which is the first attempt to measure the susceptibility to nudges directly by a scale. There are four steps for developing CPANSS, including Scale Dimensions, Item Generation, Exploratory Factor Analysis (n = 294), and Confirmatory Factor Analysis (n = 293) with appropriate procedures. Results: The five-factor 21-item CPANSS with good reliability and validity fitted the data reasonably well. Conclusion: The CPANSS was to provide a new tool for policymakers to design effective nudges in changing and promoting physical activity in college settings, and to provide a method for scholars to promote other healthy behaviors for different target groups.

Are You "Nudgeable"? Factors Affecting the Acceptance of Healthy Eating Nudges in a Cafeteria Setting

Research has identified nudging as a promising and effective tool to improve healthy eating behavior in a cafeteria setting. However, it remains unclear who is and who is not “nudgeable” (susceptible to nudges). An important influencing factor at the individual level is nudge acceptance. While some progress has been made in determining influences on the acceptance of healthy eating nudges, research on how personal characteristics (such as the perception of social norms) affect nudge acceptance remains scarce. We conducted a survey on 1032 university students to assess the acceptance of nine different types of healthy eating nudges in a cafeteria setting with four influential factors (social norms, health-promoting collaboration, responsibility to promote healthy eating, and procrastination). These factors are likely to play a role within a university and a cafeteria setting. The present study showed that key influential factors of nudge acceptance were the perceived responsibility to promote healthy eating and health-promoting collaboration. We also identified three different student clusters with respect to nudge acceptance, demonstrating that not all nudges were accepted equally. In particular, default, salience, and priming nudges were at least moderately accepted regardless of the degree of nudgeability. Our findings provide useful policy implications for nudge development by university, cafeteria, and public health officials. Recommendations are formulated for strengthening the theoretical background of nudge acceptance and the susceptibility to nudges.

Nudging food service users to choose fruit- and vegetable-rich items: Five field studies

Although nudging has been found to promote the choice of healthy foods in lab studies and ad-hoc field studies, relatively little research is available regarding effectiveness in real food venues that operate for profit. The paucity of empirical studies providing "proof of implementation" reveals the difficulty of applying previous empirical findings on nudging to mass-eating food services contexts, which serve meals to a lot of individuals daily. Based on the typology of choice architecture in food choice contexts, we closely collaborated with the in-house food service operator to devise and implement five nudge interventions to promote fruits and vegetables (FV) in university cafeterias. Each study was conducted for one 12-week semester or more over a three-year period. In the first two studies, non-verbal point-of-purchase prompting increased the choice of kale/spinach supplemented smoothies and whole fruits from baskets. In Study 3, the combination of sizing and point-of-purchase non-verbal prompting increased the sale of large size vegetable-rich bowls from a stir-fry grill. In Study 4, the proximity type of nudging by altering the position of the healthier option in a sandwich bar in combination with non-verbal prompting increased the sale of sandwiches containing spinach. In Study 5, the combination of sizing and proximity of large vs. small sized plates and serving spoons had no effect on sale of self-serve items in a salad bar. All the interventions except for Study 5 produced a moderate effect in increasing the choice of FV-rich items. We recommend that hospitality and food service operators consider operational parameters and simultaneously adopt more than one nudging components to achieve a sizable effect. Future randomized controlled trials are needed to implement choice architecture techniques in collaboration with food service companies.

Cafeteria Online: Nudges for Healthier Food Choices in a University Cafeteria-A Randomized Online Experiment

Many people do not consume as much healthy food as recommended. Nudging has been identified as a promising intervention strategy to increase the consumption of healthy food. The present study analyzed the effects of three body shape nudges (thin, thick, or Giacometti artwork) on food ordering and assessed the mediating role of being aware of the nudge. Students (686) and employees (218) of a German university participated in an online experimental study. After randomization, participants visited a realistic online cafeteria and composed a meal for themselves. Under experimental conditions, participants were exposed to one out of three nudges while choosing dishes: (1) thin body shape, (2) thick body shape, and (3) the Giacometti artwork nudge. The Giacometti nudge resulted in more orders for salad among employees. The thin and thick body shape nudges did not change dish orders. Awareness of the nudge mediated the numbers of calories ordered when using the Giacometti or thin body shape nudges. These findings provide useful insights for health interventions in occupational and public health sectors using nudges. Our study contributes to the research on the Giacometti nudge by showing its effectiveness when participants are aware (it is effective under conditions where it is consciously perceived).

Equity Effects of Dietary Nudging Field Experiments: Systematic Review

Background: Dietary behaviours are among the key modifiable risk factors for non-communicable diseases. Importantly, dietary behaviours vary substantially between groups and individuals with different socioeconomic positions, with more disadvantaged groups and individuals being exposed to more dietary risk factors. The goal of this review is to summarise the existing research on equity effects of dietary nudging interventions. Methods: Systematic review of nudging interventions conducted in a field setting that report an observable indicator of dietary behaviour, include a control group, and report effect sizes stratified by indicators of socioeconomic status as outlined in the PROGRESS-Plus framework. Two databases (scopus, Pubmed) were searched (last search June 2021), and 18 articles with 19 studies (k = 46 equity comparisons) were included. Risk of bias was assessed using the ROBINS-I tool. Due to heterogeneity in equity dimensions and study outcomes, a harvest plot was used to summarise data. Results: The majority of equity comparisons (38 out of 46) were available for cognitive nudges. Most of these (22 out of 38 comparisons) found that cognitive nudges worked equally well in more and less disadvantaged populations; however, in 12 out of the 38 comparisons, they favoured those who were less disadvantaged. Two out of four comparisons on behavioural nudges favoured more disadvantaged persons. Conclusions: The differential effects of dietary nudging interventions in this review can contribute to increases in health inequalities. At the same time, a substantial number of interventions showed no equity effects. Importantly, this review suggests that more research on nudging interventions and health equity is needed. Future interventions should report effect sizes stratified by indicators of social inequality. Systematic Review Registration: PROSPERO (CRD42019137469).