From motivation to mediterranean diet intention and behavior: a combined self-determination theory and theory of planned behavior approach

OBJECTIVE

The Mediterranean diet (MD) is recognized as one of the healthiest and most sustainable dietary patterns worldwide. This study combines the Theory of Planned Behavior (TPB) and Self-Determination Theory (SDT) alongside past MD adherence behavior to predict MD adherence among young and adult Italians.

METHODS AND MEASURES

Using a two-wave prospective design, 706 participants (Women = 60.5%, mean age = 31.82) completed measures of past behavior, SDT and TPB variables at baseline (T1) and reported their adherence behavior to MD two weeks later (T2).

RESULTS

Results revealed that both intention and past adherence to MD predicted actual adherence. In turn, affective attitude, descriptive norm, perceived behavioral control (PBC), and autonomous motivation were positively associated with intention. Past adherence further predicted autonomous motivation, affective attitude, and PBC, and indirectly influenced MD adherence at T2 through its effect on these factors and intention. Finally, invariance tests showed no differences between women and men and between student and non-student samples.

CONCLUSION

Overall, our findings support the integration of TPB and SDT, emphasizing the need for interventions that address both conscious decision-making and established dietary habits, acknowledging the multifaceted nature of dietary behavior change.

Place effects on adult obesity and cardiometabolic health: Evidence from a natural experiment

Despite considerable evidence on clustering of obesity within geographic areas causal estimates of place effects on cardiometabolic health, and their causal pathways, remain rare. This study utilizes a natural experiment based on the quasi-random assignment of military families to different installations to show that adults exposed to places with higher obesity prevalence have a greater likelihood of obesity and other downstream cardiometabolic conditions. We find no evidence to support shared environments as a causal pathway for these place effects, suggesting that alternate pathways such as social influence may be at play. We also provide the first real-world evidence on the effect of exogenous exposure to obesogenic places on theoretically-grounded social influence constructs, such as social norms and social networks. We find evidence of place effects on individuals' perceptions of descriptive norms and obesogenic composition of social networks, but not on injunctive and subjective norms. The mediating role of social influence in explaining place effects on cardiometabolic health should be examined further in future work.

COVID-19 in college: Risk perception and planned protective behavior

Objective: The Theory of Planned Behavior has been applied to COVID-19 protective behaviors, but evidence suggests this theory may be less predictive over time and less valid in individualistic societies. The current study applied this theory among American college students as vaccines became available and added perceived risk. Participants: 242 undergraduate students at two universities. Methods: Participants completed an online survey and analyses were conducted using PROCESS. Results: Perceived risk was indirectly related to protective behavior via intentions which were significantly impacted by positive attitudes, descriptive norms, and perceived behavioral control. Conclusions: Even within an individualistic culture and when vaccines were becoming available, the Theory of Planned Behavior predicts protective behaviors. Including risk perception also furthers understanding of this theory by identifying one factor related to norms and perceived behavioral control. These results may inform the design of interventions designed to increase compliance with pandemic-related policies and other positive behaviors.

A qualitative study among youth in Malaysia: What drives the purchase of roasted chicken products by young people seeking a better quality of life?

This study was aimed to assess internal and external factors related to youths' consumption behavior towards roasted chicken products. Qualitative interview was conducted with 30 selected respondents aged 15-20, 21-25 and 26 to 30 from a university and two high schools at Serdang, Selangor. An audio recorder was used to gather qualitative data over two months. A thematic content analysis was applied to identify the needed information, comprising of transcription, coding and theme development. Results disclosed that respondents in this study implied physiological attributes (delicious, tastiness, crispy texture, good flavour, brown colour, smoky aroma, own eating preference), personality attributes (availability, good hygiene, health concern), reference groups (friends, family members) and culture (family lifestyle, early life feeding behaviour) as significant factors that drive their purchase of roasted chicken products. This study's results also disclosed that the most prioritized factors were brown colour, health concern, friends and family lifestyle. The results of this study further identify physiological and personality attributes as internal factors, and reference groups and culture as external factors. Hence, this study concluded that internal factors (physiological, personality) and external factors (reference groups, culture) as essential factors in influencing youths' purchase of roasted chicken products. Thus, this study's outcome is beneficial for the vendors to boost their sales as well as promoting better ways of selecting foods to reduce the risk of non-communicable diseases amongst the youth in Malaysia.

When Students Patronize Fast-Food Restaurants near School: The Effects of Identification with the Student Community, Social Activity Spaces and Social Liability Interventions

US schools have fast-food restaurants nearby, encouraging student patronage, unhealthy consumption, and weight gain. Geographers have developed an activity space framework which suggests this nearby location effect will be moderated by whether people perceive the location as their activity space. Therefore, we study whether students perceive a fast-food restaurant near school as their activity space, and whether social marketing messages can change that perception. We conducted six studies: a secondary data analysis with 5986 students, a field experiment with 188 students, and four lab experiments with 188, 251, 178, and 379 students. We find that students who strongly identify with their student community patronize a fast-food restaurant near school (vs. farther away) because they view it as their activity space, while students who weakly identify do not. For example, in our field experiment, 44% vs. 7% of students who strongly identified with the student community patronized the near versus farther restaurant, while only 28% versus 19% of students who weakly identified patronized the near and farther restaurants comparably. We also find that to deter the strong identifiers, messages should convey that patronage is a social liability, e.g., portray student activism against fast food. We show that standard health messages do not change perceptions of restaurants as social activity spaces. Thus, to combat the problem of fast-food restaurants near schools causing unhealthy consumption, policy and educational interventions should focus on students who strongly identify with their student community and find ways to weaken their perceptions that fast-food restaurants near schools are their activity spaces.

Social Environmental Predictors of Lapse in Dietary Behavior: An Ecological Momentary Assessment Study Amongst Dutch Adults Trying to Lose Weight

BACKGROUND

When losing weight, most individuals find it difficult to maintain a healthy diet. Social environmental conditions are of pivotal importance in determining dietary behavior. To prevent individuals from lapsing, insight in social environmental predictors of lapse in dietary behavior is needed.

PURPOSE

Identify social environmental predictors of lapse in dietary behavior, using ecological momentary assessment (EMA) amongst Dutch adults trying to lose weight.

METHODS

Adults (N = 81) participated in two 7-day EMA weeks. Six times a day semi-random prompts were sent. At each prompt, participants indicated whether a lapse had occurred and responded to questions assessing social support, descriptive norm, injunctive norm, social pressure, presence of others, and current location. Generalized estimating equations were used to examine associations with lapse.

RESULTS

Injunctive norm (OR = 1.07, 95% CI = 1.03-1.11), descriptive norm (OR = 1.04, 95% CI = 1.02-1.07), and social pressure (OR = 1.09, 95% CI = 1.05-1.14), all toward diverting from diet plans, predicted lapses. Social support toward sticking to diet plans and presence of others did not predict lapses. When controlling for a prior lapse, all other associations became nonsignificant. Lapses occurred most often at home and gradually occurred more often during the day.

CONCLUSIONS

Traditional public health perspectives have mainly focused on individual choice and responsibility for overweight related unhealthy lifestyles. This study shows that there may be opportunities to enhance intervention programs by also focusing on social norms and social pressure. The involvement of partners or housemates may create more awareness of the impact of (unintentional) social pressure on risk of lapsing, and reduce the level of exerted social pressure.

An (un)healthy social dilemma: a normative messaging field experiment with flu vaccinations

BACKGROUND

Influenza seasons can be unpredictable and have the potential to rapidly affect populations, especially in crowded areas. Prior research suggests that normative messaging can be used to increase voluntary provision of public goods, such as the influenza vaccine. We extend the literature by examining the influence of normative messaging on the decision to get vaccinated against influenza.

METHODS

We conduct a field experiment in conjunction with University Health Services, targeting undergraduate students living on campus. We use four posters, randomized by living area clusters to advertise flu vaccination clinics during the Fall. The wording on the posters is varied to emphasize the individual benefits of the vaccine, the social benefits of the vaccine or both benefits together. We collect survey data for those vaccinated at the vaccination clinics, and for those not vaccinated via an online survey.

RESULTS

We find that any normative message increases the percentage of students getting the flu vaccine compared with no message. In terms of the likelihood of getting the flu vaccine, emphasizing both the individual and social benefits of vaccination has the largest increase in the vaccination rate (19-20 percentage point increase). However, flu vaccinations did not reach the herd immunity threshold (70% of students vaccinated).

CONCLUSIONS

This study provides evidence that there is a pro-social component that is relevant in individual vaccination decisions which should be accounted for when designing vaccination campaigns. The results of this normative, pro-social messaging experiment could be extended to other at-risk communities where the number of background risks is much larger. This is especially relevant nowadays, as other seasonal vaccines are being rolled out and younger adults are the ones with the lowest uptake.

Psychological Barriers to Sustainable Dietary Patterns: Findings from Meat Intake Behaviour

Sustainable diets are patterns that change consumer behaviour towards more balanced and plant-based habits. This study investigates the effect of individuals’ predisposition to adopt sustainable diets while reducing meat intake by measuring their psychological proximity to meat. Using an online consumer-based platform, a cross-sectional survey collected responses from 497 individuals. Questionnaire items included 43 questions prospected from the literature, coded as practical and essential barriers and measured on a modified 7-point Likert scale. The results showed some paradoxes, as a high predisposition to adopt a sustainable diet coexists with a high predisposition to consume animal-based proteins. The main perceived barrier to adopting a plant-based diet was the enjoyment of eating meat, followed by the lack of information about plant-based diets. Barriers related to meat alternatives remained the highest above all the others. It confirms that, for local consumers, meat remains a usual option and is easier to prepare. When investigating the moderating effect of barriers on the predisposition to behaviours towards meat intake reduction, no effect was confirmed. However, we found a U-shaped moderating effect for plant-based meal increase, confirming the psychological proximity of the meat consumption effects under the lens of the Construal Level Theory and Transtheoretical Model. These findings call for further research on the effectiveness of measuring psychological barriers related to sustainable diet adoption.

The use of food swaps to encourage healthier online food choices: a randomized controlled trial

BACKGROUND

Online grocery stores offer opportunities to encourage healthier food choices at the moment that consumers place a product of their choice in their basket. This study assessed the effect of a swap offer, Nutri-Score labeling, and a descriptive norm message on the nutrient profiling (NP) score of food choices in an online food basket. Additionally explored was whether these interventions made it more motivating and easier for consumers to select healthier foods and whether potential effects were moderated by consumer health interest.

METHODS

Hypotheses were tested with a randomized controlled trial (RCT) in a simulated online supermarket. Dutch participants (n = 550) chose their preferred product out of six product options for four different categories (breakfast cereals, crackers, pizza, and muesli bars). Participants were randomly allocated to one of eight groups based on the interventions in a 2 (Nutri-Score: present, not present) X 2 (swap offer: present, not present) X 2 (norm message: present, not present) between subject design. The primary outcome was the difference in combined NP score of product choices, for which a lower score represented a healthier product.

RESULTS

Swap offer (B = - 9.58, 95% CI: [- 12.026; - 7.132], Ƞ² = 0.098) and Nutri-Score labeling (B = - 3.28, 95% CI: [- 5.724; -.829], Ƞ² = 0.013) significantly improved the combined NP score compared to the control condition (NP score M = 18.03, SD = 14.02), whereas a norm message did not have a significant effect (B = - 1.378, 95% CI [- 3.825; 1.070], Ƞ² = 0.002). No evidence was found that interventions made it more motivating or easier for consumers to select healthier food, but situational motivation significantly influenced the healthiness score of food choices for both swap offer (b = - 3.40, p < .001) and Nutri-Score (b = - 3.25, p < .001). Consumer health interest only significantly moderated the influence of Nutri-Score on ease of identifying the healthy food option (b = .23, p = .04).

CONCLUSIONS

Swap offer and Nutri-Score labeling were effective in enhancing healthy purchase behavior in the online store environment.

TRIAL REGISTRATION

This study was retrospectively registered in the ISRCTN database on 02-09-2021 ( ISRCTN80519674 ).

Can Social Cognitive Theory Influence Breakfast Frequency in an Institutional Context: A Qualitative Study

Breakfast is considered an important meal, especially for people who are about to commence a long or demanding workday, and for roles that may involve physical tasks and a requirement to remain alert and vigilant in potentially high-risk situations. This study looks at breakfast consumption influences within two workplace institutional settings, namely military and mining. Semi-structured interviews were conducted with military personnel (n = 12) and mining employees (n = 12) to understand their breakfast consumption behaviour at work and at home, and the associated behavioural influences. The interview questions were framed by social cognitive theory. Overall, cognitive and environmental influences were the most prominent influences on breakfast consumption, less evident were behavioural influences. A negative stereotype of workplace institutional food services emerged as one of the most significant barriers to breakfast consumption for those already at work. Considerations of environmental influences on behaviour may need to be broadened beyond physical barriers and social influences, to include perceptions of the behavioural environment. Programs that aim to increase breakfast consumption must create areas where their employees want to go. Food systems need to ensure nutritious, quality, and appealing food is available. Interventions need to increase participants’ knowledge, improve their attitudes, and create positive expectations for breakfast.

Social connections and the healthfulness of food choices in an employee population

Unhealthy food choice is an important driver of obesity, but research examining the relationship of food choices and social influence has been limited. We sought to assess associations in the healthfulness of workplace food choices among a large population of diverse employees whose food-related social connections were identified using passively collected data in a validated model. Data were drawn from 3 million encounters where pairs of employees made purchases together in 2015-2016. The healthfulness of food items was defined by 'traffic light' labels. Cross-sectional simultaneously autoregressive models revealed that proportions of both healthy and unhealthy items purchased were positively associated between connected employees. Longitudinal generalized estimating equation models also found positive associations between an employee's current food purchase and the most recent previous food purchase a coworker made together with the employee. These data indicate that workplace interventions to promote healthy eating and reduce obesity should test peer-based strategies.

Increasing vegetables purchase with a descriptive-norm message: A cluster randomized controlled intervention in two university canteens

Exposure to social norms is a popular way to foster healthy food behavior. Testing the robustness of this effect, we report a field study assessing the impact of a vegetable-related descriptive norm message on vegetables purchase. The first contribution was to rely on a cluster randomized crossover design: Two canteens were randomly selected to display either a vegetable-related or a neutral-behavior norm message. After a first period of data collection, the displays were reversed for a second period: The number of vegetable portions on the main plate were recorded before, during and after the message display (N = 12.994). The second contribution was to test the impact of a message describing vegetables as the normative choice beyond the mere selection of vegetables, on the quantity of vegetables purchased in lunches containing some. Results indicated that the vegetable-related norm message led to a sustained probability of choosing vegetables, contrary to a decrease observed in the control condition. Moreover, students who ordered vegetables ordered a higher quantity when exposed to a vegetable-related message than before whereas quantity declined in the control condition. By treating both canteens as experimental and control and by analyzing both the presence and the amount of vegetables, these results extend and strengthen those previously observed, bringing support for the effectiveness of a descriptive norm message in eliciting healthier food behavior.

Does exposure to socially endorsed food images on social media influence food intake?

Social norms can influence the consumption of high and low energy-dense (HED/LED) snack foods. Such norms could be communicated via social media, however, there is little experimental research investigating this possibility. This laboratory study aimed to investigate the acute effect of socially endorsed social media posts on participants' eating behaviour. Healthy women students (n = 169; mean age = 20.9; mean BMI = 23.3) were assigned to either a HED, LED or control condition, where they viewed three types of images (HED foods, LED foods and interior design as control), but only one type was socially endorsed (e.g. in the control condition, only interior design images were socially endorsed). Participants completed questionnaires and were also provided a snack buffet of grapes and cookies. One-way ANOVA revealed a significant main effect of condition on participants' relative consumption of grapes (percentage of grapes consumed out of total food intake), for both grams and calories consumed (both ps < .05). Follow-up t-tests revealed that participants consumed a larger proportion of grapes (grams and calories) in the LED condition vs HED condition (all ps < .05), and a larger proportion of calories from grapes in the LED compared to control condition (p < .05). These findings suggest that exposure to socially endorsed images of LED food on social media could nudge people to consume more of, and derive more calories from these foods in place of HED foods. Further research is required to examine the potential application of these findings.

How Social Norms Affect Consumer Intention to Purchase Certified Functional Foods: The Mediating Role of Perceived Effectiveness and Attitude

Certified functional foods (CFFs) are approved by relevant authorities because of demonstrable efficacy. However, social norms affect consumer perceptions regarding CFFs, and their attitudes toward CFFs remain unclear. Drawing on social influence theory, this study explored how social norms (i.e., descriptive and injunctive) affect consumer perceptions and willingness to purchase CFFs. Consumers of CFFs in Taiwan were invited to participate in this study, and 398 valid questionnaires were received. Collected data were assessed through structural equation modeling. The results revealed that descriptive and injunctive norms exerted a positive effect on perceptions of the effectiveness of CFFs. However, although injunctive norms exerted a positive effect on consumer attitude, the effect of descriptive norms on attitude was not significant. Furthermore, consumer perceptions on the effectiveness of CFFs affected their attitude toward CFFs, consequently increasing their intention to purchase CFFs. This study contributes to the literature by providing insights into the relationship between social norms, perceived effectiveness, and attitudes regarding CFFs. The results of this study provide directions to CFF marketers for developing marketing strategies and establishing marketing communication strategies from the perspective of social influence.

Interventions to change purchasing behaviour in supermarkets: a systematic review and intervention content analysis

This systematic review and intervention content analysis used behavioural science frameworks to characterise content and function of interventions targeting supermarket shoppers' purchasing behaviour, and explore if coherence between content and function was linked to intervention effectiveness. Study eligibility: in-store interventions (physical supermarkets) with control conditions, targeting objectively measured food and/or non-alcoholic drink purchases, published in English (no date restrictions). Eleven electronic databases were searched; reference lists of systematic reviews were hand-searched. Methodological quality was assessed using the GATE checklist. A content analysis was performed to characterise intervention content and function, and theoretical coherence between these, using the Behaviour Change Wheel, Behaviour Change Techniques Taxonomy, and Typology of Interventions in Proximal Physical Micro-Environments (TIPPME). Forty-six articles (49 interventions) met inclusion criteria; 26 articles (32 interventions) were included in the content analysis. Twenty behaviour change techniques (BCTs), and four TIPPME intervention types were identified; three BCTs ('Prompts/cues', 'Material incentive', and 'Material reward') were more common in effective interventions. Nineteen interventions solely employed theoretically appropriate BCTs. Theoretical coherence between BCTs and intervention functions was more common in effective interventions. Effective interventions included price promotions and/or in-store merchandising. Future research should explore the effect of specific BCTs using factorial study designs. PROSPERO Registration: CRD42017071065.

A randomised experiment of health, cost and social norm message frames to encourage acceptance of swaps in a simulation online supermarket

Offering lower-energy food swaps to customers of online supermarkets could help to decrease energy (kcal) purchased and consumed. However, acceptance rates of such food swaps tend to be low. This study aimed to see whether framing lower-energy food swaps in terms of cost savings or social norms could improve likelihood of acceptance relative to framing swaps in terms of health benefits. Participants (n = 900) were asked to shop from a 12-item shopping list in a simulation online supermarket. When a target high-energy food was identified in the shopping basket at check-out, one or two lower-energy foods would be suggested as an alternative (a “swap”). Participants were randomised to only see messages emphasising health benefits (fewer calories), cost benefits (lower price) or social norms (others preferred this product). Data were analysed for 713 participants after exclusions. Participants were offered a mean of 3.17 swaps (SD = 1.50), and 12.91% of swaps were accepted (health = 14.31%, cost = 11.49%, social norms = 13.18%). Swap acceptance was not influenced by the specific swap frame used (all p > .170). Age was significantly and positively associated with swap acceptance (b = 0.02, SE = 0.00, p < .001), but was also associated with smaller decreases in energy change (b = 0.46, SE = .19, p = .014). Overall, offering swaps reduced both energy (kcal) per product (b = -9.69, SE = 4.07, p = .017) and energy (kcal) per shopping basket (t₇₁₂ = 11.09, p < .001) from pre- to post-intervention. Offering lower-energy food swaps could be a successful strategy for reducing energy purchased by customers of online supermarkets. Future research should explore alternative solutions for increasing acceptance rates of such swaps.

Social modeling of food choices in real life conditions concerns specific food categories

The social context of eating has a profound effect on consumption choices. Social modeling, that involves using others' behavior as a guide for appropriate consumption, has been well documented for food intake, but less is known about social modeling of food choices. Moreover, social modeling has mainly been studied in laboratory settings. We conducted an observational study in a self-service canteen to examine whether the food choices of an individual were influenced by the choice of the person ahead in the queue. We recorded food choices of 546 individuals (333 men and 211 women) and those of the person in front of them in the queue along a linear buffet. Starters were sub-categorized into salads, mixed starters (e.g. avocado shrimp mayonnaise), and cold meat starters, and desserts were sub-categorized into fruits, dairy products and pastries. There was a significantly higher probability of taking a starter in general (OR = 1.65, IC = 1.06-2.57, p = 0.03), a salad (OR = 1.78, CI = 1.08-2.93, p = 0.02), a mixed starter (OR = 2.98, CI = 1.42-6.05, p < 0.01), but not a cold meat, if the person ahead in the queue also took one compared to when the person ahead did not take one. No significant modelling was found for desserts which may be because almost all participants took a dessert. These results highlight that social modeling influences food choices, and that this phenomenon can be observed in a real life setting. These data also suggest that some food categories, such as starters, could be more susceptible to social modeling than are others. Finally, we observed modeling both between familiar and unfamiliar participants, which suggests that social norms could be used to promote healthier eating in a range of settings including friendship groups.

Intention to Receive the COVID-19 Vaccination in China: Application of the Diffusion of Innovations Theory and the Moderating Role of Openness to Experience

COVID-19 has caused a devastating impact on public health and made the development of the COVID-19 vaccination a top priority. Herd immunity through vaccination requires a sufficient number of the population to be vaccinated. Research on factors that promote intention to receive the COVID-19 vaccination is warranted. Based on Diffusion of Innovations Theory, this study examines the association between the perceived efficacy of the COVID-19 vaccination, use of social media for COVID-19 vaccine-related information, openness to experience and descriptive norm with the intention to receive the COVID-19 vaccination, and the moderating role of openness to experience among 6922 university students in mainland China. The intention to receive the free and self-paid COVID-19 vaccination is 78.9% and 60.2%, respectively. Results from path analyses show that perceived efficacy of the COVID-19 vaccination, use of social media for COVID-19 vaccine-related information, and openness to experience and descriptive norm are all positively associated with the intention to receive COVID-19 free and self-paid vaccination. The association between the perceived efficacy of the COVID-19 vaccination and descriptive norm with the intention to receive the COVID-19 vaccination is stronger among those with a lower level of openness to experience. Our findings support the usefulness of Diffusion of Innovations Theory and the moderating role of openness of experience in explaining intention to receive the COVID-19 vaccination.

Nudging Consumers toward Healthier Food Choices: A Field Study on the Effect of Social Norms

Food choices influence the health of individuals, and supermarkets are the place where part of the world population makes their food choices on a daily basis. Different methods to influence food purchasing habits are used, from promotions to food location. However, very few supermarket chains use social norms, the human need to conform to the perceived behavior of the group, to increase healthy food purchase habits. This research seeks to understand how a social norm nudge, a message conveying fruit and vegetable purchasing norms positioned in strategic places, can effectively change food choices. Using data from an intervention in a Portuguese supermarket, the fruit and vegetable purchase quantities of 1636 customers were measured over three months and compared with the corresponding period of the previous year. The results show that the nudge intervention positively affected those whose purchasing habits are categorized as less healthy, while those with healthy habits were slightly negatively affected. Moreover, a follow-up inferential statistical analysis allows us to conclude that applying this intervention at a larger scale would deliver significant financial results for the supermarket chain in which the study took place, by decreasing the costs related to produce perishability while simultaneously improving the health of the consumer and the sustainability of the planet.

A nudge in the right direction: the role of food choice architecture in changing populations' diets

Populations' diets typically fall short of recommendations. The implication of this on ill health and quality of life is well established, as are the subsequent health care costs. An area of growing interest within public health nutrition is food choice architecture; how a food choice is framed and its influence on subsequent food selection. In particular, there is an appeal to manipulating the choice architecture in order to nudge individuals' food choice. This review outlines the current understanding of food choice architecture, theoretical background to nudging and the evidence on the effectiveness of nudge strategies, as well as their design and implementation. Interventions emphasising the role of nudge strategies have investigated changes to the accessibility, availability and presentation of food and the use of prompts. Empirical studies have been conducted in laboratories, online and in real-world food settings, and with different populations. Evidence on the effectiveness of nudge strategies in shifting food choice is encouraging. Underpinning mechanisms, not yet fully explicated, are proposed to relate to salience, social norms and the principle of least effort. Emerging evidence points to areas for development including the effectiveness of choice architecture interventions with different and diverse populations, and the combined effect of multiple nudges. This, alongside further examination of theoretical mechanisms and guidance to engage and inspire across the breadth of food provision, is critical. In this way, the potential of choice architecture to effect meaningful change in populations' diets will be realised.

Increasing the Proportion of Plant-Based Foods Available to Shift Social Consumption Norms and Food Choice among Non-Vegetarians

Increasing the relative availability of plant-based (versus animal source) foods seems promising in shifting consumption, but it remains unknown how and under what circumstances this happens. We performed two availability manipulations including different foods. The impact on food choice, social norm perceptions about what others do (descriptive) or approve of (injunctive), and salience was assessed. Non-vegetarian participants were visually (Study 1, n = 184) or physically (Study 2, n = 276) exposed to (a) four plant-based and two animal source foods or (b) vice versa. Participants chose one food item, either hypothetically (Study 1) or actually (Study 2), and reported the perceived social norms and salience of plant-based and animal source foods. The results showed no direct effects on food choice, injunctive norms, or salience. An increased proportion of plant-based (versus animal source) foods was interpreted in Study 1 as plant-based foods being less often chosen by others, whereas in Study 2, these foods were interpreted as being more often chosen (marginally significant), while animal source foods were interpreted as being less often chosen. The results suggest that a higher availability of plant-based foods influences descriptive norms, but future research should examine aspects potentially contributing to the contradictory normative interpretations (e.g., norm salience).

A systematic review of school meal nudge interventions to improve youth food behaviors

Background

School meal programs have a large reach and thus are ideal environments in which to implement interventions targeting improved youth eating behaviors and reduced food waste. This systematic review summarizes the evidence on the effectiveness of school meal nudge interventions on influencing children’s eating and waste behaviors.

Methods

Inclusion criteria required studies have participants in primary or secondary school (grades K-12) with interventions that occurred during school lunch or breakfast in the cafeteria and included at least one of the following outcomes: selection, consumption, waste, or school meal participation. Analyses of intervention outcomes were restricted to studies of strong and moderate quality.

Results

Twenty-nine studies were included in the quality assessment. Included interventions fell into three categories: 1) placement/convenience, 2) marketing/promotion, or 3) variety/portions. The 20 strong and moderate quality studies included in outcome analyses generally used strong data collection methods and study designs, but were limited by an overall lack of intervention fidelity checks. Multi-component interventions often did not use methods that allowed for separate analyses of outcomes for different intervention components.

Conclusions

School meal nudge interventions were positively associated with food selection, and had an inconsistent relationship with food consumption. There were few studies evaluating the impact of nudge interventions on meal participation or food waste. The limited evidence available links nudges to improved meal participation, as well as undesirable increases in food waste. Future research in this area should use methods that incorporate implementation metrics, attend to systems factors, and allow the outcomes of individual intervention components to be isolated.

Neighbourhood fast food exposure and consumption: the mediating role of neighbourhood social norms

Background

The association between the residential fast food environment and diet has gained growing attention. However, why the food environment affects food consumption is under-examined. This study aimed to investigate neighbourhood social norms with respect to fast food consumption as a potential mediating pathway between residential fast food outlet exposure and residents’ fast food consumption.

Methods

A correlational study was conducted in which a nationwide sample of 1038 respondents living across The Netherlands completed a survey. Respondents reported their fast food consumption (amount/week) as well as perceived descriptive and injunctive norms regarding fast food consumption in their neighbourhood. Fast food outlet exposure was measured by the average count of fast food outlets within a 400 m walking distance buffer around the zip-codes of the respondents, using a retail outlet database. Regression models were used to assess associations between residential fast food outlet exposure, fast food consumption, and social norm perceptions, and a bootstrapping procedure was used to test the indirect -mediation- effect. Separate analyses were performed for descriptive norms and injunctive norms.

Results

There was no overall or direct association between residential fast food outlet exposure and residents’ fast food consumption. However, fast food outlet exposure was positively associated with neighbourhood social norms (descriptive and injunctive) regarding fast food consumption, which in turn were positively associated with the odds of consuming fast food. Moreover, results of the bootstrapped analysis provided evidence of indirect effects of fast food outlet exposure on fast food consumption, via descriptive norms and injunctive norms.

Conclusions

In neighbourhoods with more fast food outlets, residents were more likely to perceive fast food consumption in the neighbourhood as more common and appropriate. In turn, stronger neighbourhood social norms were associated with higher fast food consumption. Acknowledging the correlational design, this study is the first that implies that neighbourhood social norms may be a mediating pathway in the relation between the residential fast food environment and fast food consumption. Future research may examine the role of neighbourhood social norms in other contexts and explore how the changing food environment may shift our consumption norms.

Office cake culture

Purpose

The purpose of this paper is to explore the characteristics of office cake (OC) consumption and the associated attitudes and behaviours among UK office workers to gain insight into the implications for workplace health.

Design/methodology/approach

A cross-sectional online questionnaire was completed by 940 respondents. Data were analysed using descriptive statistics and cross-tabulation withχ2tests for between-group difference.

Findings

Respondents reported both positive social and negative health-related consequences of OC. OC influenced eating behaviour through increased salience and availability, and the effects of social influencing. Almost all (94.8 per cent) reported ideal OC frequency to be once/week or less. Gender and age significantly affected attitudes and behaviour.

Research limitations/implications

The questionnaire was not validated so data accuracy could have been diminished or biased. Portion size was not examined and consumption data were self-reported which could have resulted in under-reporting. Only office workers were investigated therefore results may not be applicable to other workplaces.

Practical implications

OC appears to influence both the workplace eating environment and employee eating behaviour. It could therefore affect employee health and workplace health promotion programme efficacy. However the findings suggest that nudge-based initiatives could reduce OC consumption to make workplaces healthier while retaining social benefits.

Originality/value

The present study provides the first data on OC culture and insights on how to address it sensitively. It also highlights that sweet treats used for celebration and employee recognition should be considered a relevant part of workplace food provision alongside canteens and vending.

Identifying social norms in physical aspects of food environments: A photo study

It is widely accepted that physical food environments can contribute to unhealthy eating, but less is known about how physical cues in these environments actually stimulate eating. Our study starts from the assumption that social norms are embedded in physical cues and aims to make an inventory of physical cues that communicate what is socially accepted as normal and/or appropriate to eat in a Dutch outside-the-home food context. In Study 1, we conducted a qualitative study in which photographs taken in self-service food environments were analyzed using strategies from photo documentation and semiology. Grounded theory was applied to identify a wide variety of specific physical cues that were ultimately grouped into 18 higher level categories of physical cues (e.g. consumption traces, product availability). Most cue categories were associated with either descriptive or injunctive social norms, but some were associated with both types. In Study 2, we aimed to quantitatively cross-validate the social norm interpretations among laypeople (N = 173) by focusing on two selected photographs. More than half of the physical cues that participants identified in these photographs as being influential had been identified in Study 1 as cues bearing a normative message. The results further indicated that other people's behavior is easier to recognize in physical food environments than signals about what ought to be done. Given the great variety of identified physical cues associated with social norms, we posit that social norms are widely embedded in food environments and might guide eating behavior. Further research should study the effects of these cues on behavior and test whether the underlying process can be attributed to social norm interpretations.

Served Portion Sizes Affect Later Food Intake Through Social Consumption Norms

Portion sizes of commercially available foods have increased, and there is evidence that exposure to portion sizes recalibrates what is perceived as 'normal' and subsequently, how much food is selected and consumed. The present study aims to explore the role of social (descriptive and injunctive) and personal portion size norms in this effect. Across two experiments, participants were either visually exposed to (Study 1, N = 329) or actually served (Study 2, N = 132) a smaller or larger than normal food portion. After 24 h, participants reported their intended consumption (Study 1) or served themselves and consumed (Study 2) a portion of that food and reported perceived portion size norms. In Study 1, visual exposure to portion size did not significantly affect intended consumption and perceived portion size norms. In Study 2, participants consumed a smaller portion of food when they were served a smaller rather than a larger portion the previous day, which was mediated by perceived descriptive and injunctive social (but not personal) portion size norms. Results suggest that being served (but not mere visual exposure to) smaller (relative to larger) portions changes perceived social norms about portion size and this may reduce future consumption of that food.

Healthy Food Labels Tailored to a High-Risk, Minority Population More Effectively Promote Healthy Choices than Generic Labels

The decades-long increase in obesity in the US has led to a number of policies aimed at improving diets, which are thought to play a significant role in obesity. Many of these policies seek to influence individuals' behaviors. Front-of-package labels providing salient, easily interpretable information to consumers have exhibited promise in helping people identify and choose healthier foods. However, behavioral economics may offer an opportunity to enhance label effectiveness. Tailoring labels to high-risk communities, including minority and rural populations, which have higher rates of diet-related diseases than the overall population, may increase the label's effectiveness. We conducted a choice experiment with supermarket shoppers on a rural American Indian reservation to test labels tailored to the local population relative to a generic label, which had previously been identified as highly effective in the general population. Results show that while the generic label continues to be quite effective in encouraging healthier choices, the label that is tailored to the local community is more effective, resulting in a marked increase in the premium shoppers were willing to pay for a healthy item. Tailoring healthy food labeling systems using insights from behavioral economics may increase their effectiveness.

Social norm feedback reduces primary care antibiotic prescribing in a regression discontinuity study

Background

Reducing antibiotic prescribing is a priority for health authorities responsible for preventing antimicrobial resistance. Northern Ireland has high rates of antimicrobial use. We implemented a social norm feedback intervention and evaluated its impact.

Objectives

To estimate the size and duration of the effect of a social norm feedback letter to GPs who worked in the 20% of practices with the highest antimicrobial prescribing.

Methods

The letter was sent in October 2017 to 221 GPs in 67 practices. To assess the effect of the intervention, we used a sharp non-parametric regression discontinuity (RD) design, with prescribing rates in the four calendar quarters following the intervention as the outcome variables.

Results

In the quarter following the intervention (October to December 2017) there was a change of −25.7 (95% CI = −42.5 to −8.8, P = 0.0028) antibiotic items per 1000 Specific Therapeutic group Age-sex Related Prescribing Units (STAR-PU). At 1 year, the coefficient was −58.7 (95% CI = −116.7 to −0.7, P = 0.047) antibiotic items per 1000 STAR-PU. The greatest change occurred soon after the intervention. Approximately 18900 fewer antibiotic items were prescribed than if the intervention had not been made (1% of Northern Ireland’s annual primary care antibiotic prescribing).

Conclusions

A social norm feedback intervention reduced antibiotic prescribing in the intervention practices. The diminishing effect over time suggests the need for more frequent feedback. The RD method allowed measurement of the effectiveness of an intervention that was delivered as part of normal business, without a randomized trial.

Employee-Organization Pro-environmental Values Fit and Pro-environmental Behavior: The Role of Supervisors' Personal Values

This study examines the relationship among the employees-organization pro-environmental values fit (E-O PEVs fit), supervisors' PEVs and employees' pro-environmental behaviors (PEB). Informed by the PEB, organizational values and employee-organization fit literature, we propose and test hypotheses that under egoistic, altruistic and biosphere-value orientations, E-O PEVs fit versus non-fit have significant effects on employees' private-sphere PEB and public-sphere PEB, identifying supervisors' PEVs as a moderator. An empirical investigation indicates that the effect of E-O PEVs fit on employees' private-sphere PEB and public-sphere PEB varies as the value orientation differs. More specifically, under the context of altruistic and biosphere-value orientations, if the organizational PEVs do not match the employees' PEVs, especially when the former exceeds the latter, employees' PEB will rise as the organizational PEVs increase. As for egoistic value orientation, when organizational PEVs exceed employees' PEVs, not only will public-sphere PEB stop decreasing and tend to stabilize, but also private-sphere PEB will rise to a slight degree. Furthermore, compared with altruistic and biospheric values dimensions, supervisors who promote egoistic PEVs will have a more significant effect on the relationship between global E-O PEVs fit and employees' PEB. Finally, we suggest that the goals of an organization and its supervisors need to be combined within the actual situation of Chinese corporations to truly implement corporate green practices by balancing the profit goal and the environmental goal.

Assessing the effectiveness of nutrition interventions implemented among US college students to promote healthy behaviors: A systematic review

BACKGROUND:

Nutrition interventions are used to increase knowledge, change attitudes and beliefs about healthy eating, to increase skills, and promote healthy eating.

AIMS:

To review the effectiveness of published nutrition interventions implemented among college students to promote healthy behaviors.

METHODS:

The authors explored multiple electronic databases, such as ERIC, Science Direct, and EBSCOhost. Search criteria included nutritional interventions implemented among students attending US colleges, written in English, and published in peer-reviewed journals between 2000 and 2015. The authors conducted a systematic search of 1413 articles, and an in-depth review of 30 articles. The authors evaluated the following: (a) participants; (b) research design; (c) assessment instruments; (d) outcome measures; (e) results; and (f) methodological issues.

RESULTS:

Short-term interventions showed promise in promoting positive dietary changes, which can serve as a protective factor for developing overweight and obesity. Methodological issues related to lack of comparison groups and minimal long-term follow-up do not allow researchers to determine if the interventions were the cause of the change, or if these changes are sustained over time. Studies that have a comparison group, use visual displays, or have longer durations, may maximize outcomes, improving long-term effects.

CONCLUSIONS:

Nutrition interventions can effectively change dietary habits among college students. This can lead to healthy weight management and reduce the risk for overweight and obesity. Future research should consider the highlighted methodological issues to improve the quality of nutrition interventions.

Eating for Two? Protocol of an Exploratory Survey and Experimental Study on Social Norms and Norm-Based Messages Influencing European Pregnant and Non-pregnant Women's Eating Behavior

The social context is an important factor underlying unhealthy eating behavior and the development of inappropriate weight gain. Evidence is accumulating that powerful social influences can also be used as a tool to impact people's eating behavior in a positive manner. Social norm-based messages have potential to steer people in making healthier food choices. The research field on nutritional social norms is still emerging and more research is needed to gain insights into why some people adhere to social norms whereas others do not. There are indications stemming from empirical studies on social eating behavior that this may be due to ingratiation purposes and uncertainty reduction. That is, people match their eating behavior to that of the norm set by their eating companion(s) in order to blend in and be part of the group. In this project, we explore nutritional social norms among pregnant women. This population is particularly interesting because they are often subject to unsolicited advice and experience social pressure from their environment. In addition, their pregnancy affects their body composition, eating pattern, and psychosocial status. Pregnancy provides an important window of opportunity to impact health of pregnant women and their child. Nevertheless, the field of nutritional social norms among pregnant women is understudied and more knowledge is needed on whether pregnant women use guidelines from their social environment for their own eating behavior. In this project we aim to fill this research gap by means of an exploratory survey (Study 1) assessing information about social expectations, (mis)perceived social norms and the role of different reference groups such as other pregnant women, family, and friends. In addition, we conduct an online experiment (Study 2) testing to what extent pregnant women are susceptible to social norm-based messages compared to non-pregnant women. Moreover, possible moderators are explored which might impact women's susceptibility to social norms as well as cultural aspects that co-determine which social norms and guidelines exist. The project's findings could help design effective intervention messages in promoting healthy eating behavior specifically targeted to European pregnant women.

Physiological health parameters among college students to promote chronic disease prevention and health promotion

This study aimed to provide physiologic health risk parameters by gender and age among college students enrolled in a U.S. Midwestern University to promote chronic disease prevention and ameliorate health. A total of 2615 college students between 18 and 25 years old were recruited annually using a series of cross-sectional designs during the spring semester over an 8-year period. Physiologic parameters measured included body mass index (BMI), percentage body fat (%BF), blood serum cholesterol (BSC), and systolic (SBP) and diastolic (DBP) blood pressure. These measures were compared to data from NHANES to identify differences in physiologic parameters among 18–25 year olds in the general versus college-enrolled population. A quantitative instrument assessed health behaviors related to physical activity, diet, and licit drug use. Results suggest that average physiologic parameters from 18 to 25 year olds enrolled in college were significantly different from parameters of 18–25 year olds in the general population. Generally, men reported higher percentiles for BMI, SBP, and DBP than women, but lower %BF and BSC percentiles than women at each age. SBP and DBP significantly increased with age and alcohol use. Students in the lowest (5th) and highest percentiles (95th and 75th), for most age groups, demonstrated DBP, BMI, and %BF levels potentially problematic for health and future development of chronic disease based on percentiles generated for their peer group. Newly identified physiologic parameters may be useful to practitioners serving college students 18–25 years old from similar institutions in determining whether behavior change or treatment interventions are appropriate.

The Hunger Games: Using hunger to promote healthy choices in self-control conflicts

The majority of existing research and conventional wisdom would advise against shopping on an empty stomach as hunger is assumed to encourage impulsive choices that typically lead to self-control failure (i.e., favouring short-term gratifications at the expense of long-term goals). Nonetheless, through two studies the current research aims to demonstrate that hungry consumers would not always be disadvantaged when encountering a self-control conflict involving a trade-off choice between a healthy vs. a more palatable but unhealthy choice. Particularly we posit that the choice outcome of the self-control conflict is dependent on contextual cues, such that hungry consumers with the tendency to make fast decisions could benefit from following a social proof heuristic promoting the healthy options. In Study 1, we indeed observed participants' self-reported hunger to be negatively associated with state self-control, but as most participants generally experienced low levels of hunger we did not observe apparent effects of hunger on food choice (DV), and correspondingly the potential influence of the social proof heuristic in moderating the choice outcome. However, in Study 2 where hunger was manipulated, we found hungry participants making significantly less healthy choices than satiated participants, but a social proof heuristic mitigated this effect (i.e., in the presence of social proof heuristic hungry participants made just as many healthy food choices as satiated participants; and hungry participants made more healthy choices in the social proof condition than in the no heuristic condition). These findings support our approach of providing contextual cues in the environment in order to work with, rather than against, the impulsivity triggered by hunger to promote successful self-control behaviours.

Between exposure, access and use: Reconsidering foodscape influences on dietary behaviours

Good accessibility to both healthy and unhealthy food outlets is a greater reality than food deserts. Yet, there is a lack of conceptual insights on the contextual factors that push individuals to opt for healthy or unhealthy food outlets when both options are accessible. Our comprehension of foodscape influences on dietary behaviours would benefit from a better understanding of the decision-making process for food outlet choices. In this paper, we build on the fundamental position that outlet choices are conditioned by how much outlets' attributes accommodate individuals' constraints and preferences. We further argue that food outlets continuously experienced within individuals' daily-path help people re-evaluate food acquisition possibilities, push them to form intentions, and shape their preferences for the choices they will subsequently make. Doing so, we suggest differentiating access, defined as the potential for the foodscape to be used at the time when individuals decide to do so, from exposure, which acts as a constant catalyst for knowledge, intention, preferences and routine tendency. We conclude with implications for future research, and discuss consequences for public policy.

Encouraging children to eat more fruit and vegetables: Health vs. descriptive social norm-based messages

Traditional intervention approaches to promote fruit and vegetable consumption outline the health benefits of eating fruit and vegetables. More recently, social norm-based messages describing the healthy eating habits of others have been shown to increase fruit and vegetable intake in adults. Here we report two experimental studies which investigated whether exposure to descriptive social norm-based messages about the behaviour of other children and health-based messages increased fruit and vegetable intake in young children. In both studies children were exposed to messages whilst playing a board-game. After exposure to the messages, children were able to consume fruit and vegetables, as well as high calorie snack foods. Although findings were inconsistent across the two individual studies, in a pooled analysis we found evidence that both health messages and descriptive social norm-based messages increased children's fruit and vegetable intake, relative to control condition messages (p < .05). Whether descriptive social norm-based messages can be used to promote meaningful changes to children's dietary behaviour warrants further study.

•

Descriptive social norm-based and health messages were examined.

•

Health messages increased fruit and vegetable intake.

•

Descriptive social norm-based messages increased fruit and vegetable intake.

The Possible Antecedents and Consequences of Matching of Food Intake: Examining the Role of Trait Self-Esteem and Interpersonal Closeness

Although there is evidence that people tend to match their intake to that of others, less is known about the motives underlying this effect. The current study, therefore, examined the relationship between self-esteem, a specific factor that has been related to the likelihood of social matching. Further, we examined the effects of food matching on interpersonal closeness among eating companions. The sample included 89 female dyads. All dyads had free access to palatable snack food during a 15 min interaction. For each dyad the matching score was calculated, as well as both individual's trait self-esteem scores and interpersonal closeness with their eating partner. The overall degree of matching within dyads was high, replicating the findings of previous research. No relationship, however, was found between trait self-esteem and the degree of matching. Furthermore, there was no effect of matching on perceived interpersonal closeness with or liking of the other person. These results suggest that self-esteem might not be a robust predictor of matching and that matching of food intake may not result in increased perceived interpersonal closeness or liking among eating partners.