The effects of nudges on purchases, food choice, and energy intake or content of purchases in real-life food purchasing environments: a systematic review and evidence synthesis

Understanding food choice: A systematic review of reviews

The topic of consumer food choice has received much attention among researchers and stakeholders within the food industry. However, in order to better facilitate food consumption towards a more sustainable direction, we need increased knowledge and understanding of factors that influence consumers' food choice. This study is a systematic review of reviews conducted between 2017 and 2021, summarising and synthesising reviews on food choice. The aim is to provide an update of the current knowledge on consumer food choice, point out what is already known, and identify knowledge gaps to enable a prioritisation for future research. The analysis highlights decisive factors in food choice, i.e. product, available information, price, context, personal and group influences and sensory perceptions. The synthesis of findings follows a socioecological model, integrating four different levels of the social and environmental systems: the physical food environment, the social and community level, interpersonal relations and, finally, individual characteristics such as psychological and behavioural factors. Results show that behavioural patterns, influenced by strong informal institutions, such as culture and norms, can be difficult to break; for example, changing into more sustainable food behaviour. The findings suggest that more interdisciplinary research and studies in real-life settings are needed to grasp the complexity of food choice. This would allow for us to better understand consumers as social beings shaped by, among other things, the physical environment, social interactions, and culture.

Are Dutch adults equally susceptible to nudging and pricing strategies? Secondary analyses of the Supreme Nudge parallel cluster-randomised controlled supermarket trial

BACKGROUND

Supermarket interventions are promising to promote healthier dietary patterns, but not all individuals may be equally susceptible. We explored whether the effectiveness of nudging and pricing strategies on diet quality differs by psychological and grocery shopping characteristics.

METHODS

We used data of the 12-month Supreme Nudge parallel cluster-randomised controlled supermarket trial, testing nudging and pricing strategies to promote healthier diets. Participants were Dutch speaking adults aged 30-80 years and regular shoppers of participating supermarkets (n = 12) in socially disadvantaged neighbourhoods. Data on psychological characteristics (food-related behaviours; price sensitivity; food decision styles; social cognitive factors; self-control) and grocery shopping characteristics (time spent in the supermarket; moment of the day; average supermarket visits; shopping at other retailers; supermarket proximity) were self-reported at baseline. These characteristics were tested for their moderating effects of the intervention on diet quality (scored 0-150) in linear mixed models.

RESULTS

We included 162 participants from intervention supermarkets and 199 from control supermarkets (73% female, 58 (± 10.8) years old, 42% highly educated). The interventions had no overall effect on diet quality. Only five out of 23 potential moderators were statistically significant. Yet, stratified analyses of these significant moderators showed no significant effects on diet quality for one of the subgroups and statistically non-significant negative effects for the other. Negative effects were suggested for individuals with lower baseline levels of meal planning (β - 2.6, 95% CI - 5.9; 0.8), healthy shopping convenience (β - 3.0, 95% CI - 7.2; 1.3), and healthy food attractiveness (β - 3.5, 95% CI - 8.3; 1.3), and with higher levels of price consciousness (β - 2.6, 95% CI - 6.2; 1.0) and weekly supermarket visits (β - 2.4, 95% CI - 6.8; 1.9).

CONCLUSIONS

Adults with varying psychological and grocery shopping characteristics largely seem equally (un)susceptible to nudging and pricing strategies. It might be that certain characteristics lead to adverse effects, but this is not plausible, and the observed negative effects were small and statistically non-significant and may be explained by chance findings. Verification of these findings is needed in real-world trials based on larger sample sizes and with the use of more comprehensive interventions.

TRIAL REGISTRATION

Dutch Trial Register ID NL7064, 30th of May, 2018, https://onderzoekmetmensen.nl/en/trial/20990.

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.

Methods used to conceptualize dimensions of health equity impacts of public health interventions in systematic reviews

OBJECTIVES

Our aims were to, first, identify and summarize the use of methods, frameworks, and tools as a conceptual basis for investigating dimensions of equity impacts of public health interventions in systematic reviews including an equity focus. These include PROGRESS-Plus, which identifies key sociodemographic characteristics that determine health outcomes. Second, we aimed to document challenges and opportunities encountered in the application of such methods, as reported in systematic reviews.

STUDY DESIGN AND SETTING

We conducted a methodological study, comprising an overview of systematic reviews with a focus on, or that aimed to assess, the equity impacts of public health interventions. We used electronic searches of the Cochrane Database of Systematic Reviews, the Database of Promoting Health Effectiveness Reviews (DoPHER), and the Finding Accessible Inequalities Research in Public Health Database, supplemented with automated searches of the OpenAlex dataset. An active learning algorithm was used to prioritize title-abstract records for manual screening against eligibility criteria. We extracted and analyzed a core dataset from a purposively selected sample of reviews, to summarize key characteristics and approaches to conceptualizing investigations of equity.

RESULTS

We assessed 322 full-text reports for eligibility, from which we included 120 reports of systematic reviews. PROGRESS-Plus was the only formalized framework used to conceptualize dimensions of equity impacts. Most reviews were able to apply their intended methods to at least some degree. Where intended methods were unable to be applied fully, this was usually because primary research studies did not report the necessary information. A general rationale for focusing on equity impacts was often included, but few reviews explicitly justified their focus on (or exclusion of) specific dimensions. In addition to practical challenges such as data not being available, authors highlighted significant measurement and conceptual issues with applying these methods which may impair the ability to investigate and interpret differential impacts within and between studies. These issues included investigating constructs that lack standardized operationalization and measurement, and the complex nature of differential impacts, with dimensions that may interact with one another, as well as with particular temporal, personal, social or geographic contexts.

CONCLUSION

PROGRESS-Plus is the predominant framework used in systematic reviews to conceptualize differential impacts of public health interventions by dimensions of equity. It appears sufficiently broad to encompass dimensions of equity examined in most investigations of this kind. However, PROGRESS-Plus does not necessarily ensure or guide critical thinking about more complex pathways, including interactions between dimensions of equity, and with wider contextual factors, and important practical, measurement and conceptual challenges remain. The findings from investigations of equity impacts in systematic reviews could be made more useful through more explicitly rationalized and considered approaches to the design, conduct and reporting of both primary research and the reviews themselves.

Nudging plant-based alternatives to meat and dairy in a real-life online supermarket: A randomized controlled trial

A shift from predominantly animal-based to plant-based consumption can benefit both planetary and public health. Nudging may help to promote such a shift. This study investigated nudge effects on plant-based alternatives to meat and dairy in an online supermarket. We conducted a two-arm, parallel-group, randomized controlled real-life online supermarket trial. Each customer transaction was randomized to a control arm (regular online supermarket) or an intervention arm (addition of placement, hedonic property and dynamic social norm nudges promoting meat and dairy alternatives). Outcomes were the aggregate of meat and dairy alternative purchases (primary outcome), the number of meat purchases, dairy purchases, meat alternative purchases, and dairy alternative purchases (secondary), and retailer revenue (tertiary). Generalized linear mixed models with a Conway-Maxwell Poisson distribution were used to estimate incidence rate ratios (IRRs). Analyzed data included 8488 transactions by participants (n = 4,266 control arm, n = 4,222 intervention arm), out of which 2,411 (66%) were aged above 45 years, 5,660 (67%) were females, and 1,970 (23%) lived in socially disadvantaged neighborhoods. Intervention arm participants purchased 10% (IRR 1.10 (95% CI 0.99-1.23)) more meat and dairy alternatives and 16% (1.16 (0.99-1.36)) more meat alternatives than control arm participants, although these findings are not statistically significant. There was no difference in dairy alternative purchases (1.00 (0.90-1.10)). Intervention arm participants purchased 3% less meats (0.97 (0.93-1.02)) and 2% less dairy products (0.98 (0.95-1.02)) than control participants. Retailer revenue was not affected (0.98 (0.95-1.01)). Online nudging strategies alone did not lead to a statistically significant higher amount of plant-based purchases, but replication of this work is needed with increased study power. Future studies should also consider nudging strategies as part of a broader set of policies to promote plant-based purchases. TRIAL REGISTRATION: Prospectively registered on 14th of May 2022. ISRCTN16569242 (https://doi.org/10.1186/ISRCTN16569242).

Real-world nudging, pricing, and mobile physical activity coaching was insufficient to improve lifestyle behaviours and cardiometabolic health: the Supreme Nudge parallel cluster-randomised controlled supermarket trial

BACKGROUND

Context-specific interventions may contribute to sustained behaviour change and improved health outcomes. We evaluated the real-world effects of supermarket nudging and pricing strategies and mobile physical activity coaching on diet quality, food-purchasing behaviour, walking behaviour, and cardiometabolic risk markers.

METHODS

This parallel cluster-randomised controlled trial included supermarkets in socially disadvantaged neighbourhoods across the Netherlands with regular shoppers aged 30-80 years. Supermarkets were randomised to receive co-created nudging and pricing strategies promoting healthier purchasing (N = 6) or not (N = 6). Nudges targeted 9% of supermarket products and pricing strategies 3%. Subsequently, participants were individually randomised to a control (step counter app) or intervention arm (step counter and mobile coaching app) to promote walking. The primary outcome was the average change in diet quality (low (0) to high (150)) over all follow-up time points measured with a validated 40-item food frequency questionnaire at baseline and 3, 6, and 12 months. Secondary outcomes included healthier food purchasing (loyalty card-derived), daily step count (step counter app), cardiometabolic risk markers (lipid profile and HbA1c via finger prick, and waist circumference via measuring tape), and supermarket customer satisfaction (questionnaire-based: very unsatisfied (1) to very satisfied (7)), evaluated using linear mixed-models. Healthy supermarket sales (an exploratory outcome) were analysed via controlled interrupted time series analyses.

RESULTS

Of 361 participants (162 intervention, 199 control), 73% were female, the average age was 58 (SD 11) years, and 42% were highly educated. Compared to the control arm, the intervention arm showed no statistically significant average changes over time in diet quality (β - 1.1 (95% CI - 3.8 to 1.7)), percentage healthy purchasing (β 0.7 ( - 2.7 to 4.0)), step count (β - 124.0 (- 723.1 to 475.1), or any of the cardiometabolic risk markers. Participants in the intervention arm scored 0.3 points (0.1 to 0.5) higher on customer satisfaction on average over time. Supermarket-level sales were unaffected (β - 0.0 (- 0.0 to 0.0)).

CONCLUSIONS

Co-created nudging and pricing strategies that predominantly targeted healthy products via nudges were unable to increase healthier food purchases and intake nor improve cardiometabolic health. The mobile coaching intervention did not affect step count. Governmental policy measures are needed to ensure more impactful supermarket modifications that promote healthier purchases.

TRIAL REGISTRATION

Dutch Trial Register ID NL7064, 30 May 2018, https://www.onderzoekmetmensen.nl/en/trial/20990.

The Difference between PC-Based and Immersive Virtual Reality Food Purchase Environments on Useability, Presence, and Physiological Responses

Computer simulations used to study food purchasing behavior can be separated into low immersion virtual environments (LIVE), which use personal computers and standard monitors to display a scene, and high immersion virtual environments (HIVE) which use virtual reality technology such as head-mounted displays to display a scene. These methods may differ in their ability to create feelings of presence or cybersickness that would influence the usefulness of these approaches. In this present study, thirty-one adults experienced a virtual supermarket or fast-food restaurant using a LIVE system or a HIVE system. Feelings of presence and cybersickness were measured using questionnaires or physiological responses (heart rate and electrodermal activity). The participants were also asked to rate their ability to complete the set task. The results of this study indicate that participants reported a higher sense of presence in the HIVE scenes as compared to the LIVE scenes (p < 0.05). The participant's heart rate and electrodermal activity were significantly higher in the HIVE scene treatment when compared to the LIVE scene (p < 0.05). There was no difference in the participant's ability to complete tasks in the different scenes. In addition, feelings of cybersickness were not different between the HIVE and LIVE scenes.

A systems framework for implementing healthy food retail in grocery settings

BACKGROUND

Food retailers can be reluctant to initiate healthy food retail activities in the face of a complex set of interrelated drivers that impact the retail environment. The Systems Thinking Approach for Retail Transformation (START) is a determinants framework created using qualitative systems modelling to guide healthy food retail interventions in community-based, health-promoting settings. We aimed to test the applicability of the START map to a suite of distinct healthy food marketing and promotion activities that formed an intervention in a grocery setting in regional Victoria, Australia.

METHODS

A secondary analysis was undertaken of 16 previously completed semi-structured interviews with independent grocery retailers and stakeholders. Interviews were deductively coded against the existing START framework, whilst allowing for new grocery-setting specific factors to be identified. New factors and relationships were used to build causal loop diagrams and extend the original START systems map using Vensim.

RESULTS

A version of the START map including aspects relevant to the grocery setting was developed ("START-G"). In both health-promoting and grocery settings, it was important for retailers to 'Get Started' with healthy food retail interventions that were supported by a proof-of-concept and 'Focus on the customer' response (with grocery-settings focused on monitoring sales data). New factors and relationships described perceived difficulties associated with disrupting a grocery-setting 'Supply-side status quo' that promotes less healthy food and beverage options. Yet, most grocery retailers discussed relationships that highlighted the potential for 'Healthy food as innovation' and 'Supporting cultural change through corporate social responsibility and leadership'.

CONCLUSIONS

Several differences were found when implementing healthy food retail in grocery compared to health promotion settings. The START-G map offers preliminary guidance for identifying and addressing commercial interests in grocery settings that currently promote less healthy foods and beverages, including by starting to address business outcomes and supplier relationships.

Nudging oral habits; application of behavioral economics in oral health promotion: a critical review

Background

Oral health disorders significantly contribute to the global incidence of chronic diseases. Nudge interventions have demonstrated effectiveness in enhancing people's decision-making and self-management capacities in a cost-efficient manner. As a result, these interventions could be valuable tools for fostering improved oral care habits. This critical review explores potential behavioral nudges applicable to promoting oral health.

Methods

A thorough electronic literature search was conducted on Scopus, Embase, and PubMed databases for papers published post-2008. The search focused on empirical evidence concerning the direct and indirect application of Nudge theory in oral health enhancement. In addition, the investigation included the nudge intervention's role in managing common non-communicable disease risk factors (tobacco, alcohol, and sugar) and their use in other health sectors.

Results and conclusion

There is a dearth of studies on behavioral economics, particularly those involving reward and reminder techniques. However, various successful nudge interventions have been identified in other sectors that aim to improve health decisions. These include strategies encouraging healthier nutritional choices, tobacco and alcohol cessation, medication compliance, routine physical activity, and regular health check-ups. Such interventions can also have direct or indirect positive impacts on oral health. Implementing these interventions within an oral care framework could promote oral health due to similar underlying cognitive mechanisms. However, different types of nudge interventions have varying degrees of effectiveness. Furthermore, factors such as the method of delivery and the characteristics of the targeted population significantly influence the outcome of the intervention. Hence, it is imperative to conduct extensive studies in diverse socioeconomic settings to fully understand the potentials, limitations, and impacts of nudge interventions in promoting oral health.

The role of attention and health goals in nudging healthy food choice

Introduction

Nudging is a promising intervention technique that supports people in pursuing their healthy eating goals. Recent research suggests that, despite previous assumptions, disclosure of the presence of a nudge does not compromise nudge effectiveness. However, it is unknown whether attention to a nudge affects nudge effects. We assessed the role of attention systematically, by examining explicit and implicit attention to nudges, while also exploring healthy eating goals as a potential moderator.

Methods

Participants were assigned to a nudge (i.e., a shopping basket inlay with pictures of healthy items) or control condition (i.e., a shopping basket inlay with neutral pictures) and chose a snack in an experimental supermarket field study. Explicit and implicit attention (with a mobile eye-tracker) to nudges, healthiness of snack choice, and healthy eating goals were assessed.

Results

Results showed that attention to the nudge did not hamper the nudge's effect. Furthermore, individuals with strong healthy eating goals made healthier food choices in the nudge condition. Individuals with weak to non-existent healthy eating goals were not influenced by the nudge.

Discussion

Findings are in line with the viewpoint that nudging does not by definition work 'in the dark', and suggests that nudges support people in adhering to their healthy eating goal.

Do restaurants comply with reduced salt requests from consumers ordering on meal delivery apps?

BACKGROUND

Chinese urban residents consume more salt from meals prepared outside home than in the past. The purpose of this study is to understand Chinese consumer demand for salt reduction as expressed through their orders on meal delivery apps (MDAs), restaurants' willingness to promote salt reduction, and the extent to which restaurants comply with reduced salt requests.

METHODS

We analyzed consumer comments extracted from 718 restaurants on a Chinese MDA called ELEME for orders made in the July-December 2020 timeframe. A self-designed questionnaire was distributed to the restaurant managers to assess restaurants' attitude towards salt reduction upon signing up for the study, and laboratory validation was conducted to test whether dishes ordered with reduced salt requests by consumers actually contained less salt.

RESULTS

A total of 25,982 (0.7%) orders out of 3,630,798 orders contained consumer comments. Of the consumer comments, 40.6% (10,549) were about requests for less salt in dishes. Totally 91.5% of 421 surveyed restaurants showed a willingness to respond to consumers' reduced salt requests. The median sodium content measured in the reduced-salt dishes by the laboratory was significantly lower than that in their regular salt counterparts (P < 0.05).

CONCLUSIONS

We observed substantial consumer demand for salt reduction while ordering meals on the MDA and that restaurants did, in response, reduce the sodium content in the meals they provided. As meals delivered via MDAs comprise an increasing proportion of outside foods consumed, there is an opportunity for public health experts and policy makers to work with MDAs and restaurants to promote healthier food selections.

TRIAL REGISTRATION

ChiCTR2100047729.

Preventing type 2 diabetes: A research agenda for behavioural science

AIMS

The aim of this narrative review was to identify important knowledge gaps in behavioural science relating to type 2 diabetes prevention, to inform future research in the field.

METHODS

Seven researchers who have published behaviour science research applied to type 2 diabetes prevention independently identified several important gaps in knowledge. They met to discuss these and to generate recommendations to advance research in behavioural science of type 2 diabetes prevention.

RESULTS

A total of 21 overlapping recommendations for a research agenda were identified. These covered issues within the following broad categories: (a) evidencing the impact of whole population approaches to type 2 diabetes prevention, (b) understanding the utility of disease-specific approaches to type 2 diabetes prevention such as Diabetes Prevention Programmes (DPPs) compared to generic weight loss programmes, (c) identifying how best to increase reach and engagement of DPPs, whilst avoiding exacerbating inequalities, (d) the need to understand mechanism of DPPs, (e) the need to understand how to increase maintenance of changes as part of or following DPPs, (f) the need to assess the feasibility and effectiveness of alternative approaches to the typical self-regulation approaches that are most commonly used, and (g) the need to address emotional aspects of DPPs, to promote effectiveness and avoid harms.

CONCLUSIONS

There is a clear role for behavioural science in informing interventions to prevent people from developing type 2 diabetes, based on strong evidence of reach, effectiveness and cost-effectiveness. This review identifies key priorities for research needed to improve existing interventions.

Adult food choices in association with the local retail food environment and food access in resource-poor communities: a scoping review

BACKGROUND

There is a growing body of research on local retail food environments globally in both urban and rural settings. Despite this, little research has been conducted on adult food choices, local retail environments, and healthy food access in resource-poor communities. The purpose of this study is therefore to provide an overview of the evidence on adult food choices (measured as dietary intake) in association with the local retail food environment and food access in resource-poor communities (defined as low-income communities and/or households).

METHODS

We searched nine databases for studies published from July 2005 to March 2022 and identified 2426 records in the primary and updated search. Observational studies, empirical and theoretical studies, focused on adults ≤ 65 years, published in English peer-reviewed journals, examining local retail food environments and food access, were included. Two independent reviewers screened identified articles using the selection criteria and data extraction form. Study characteristics and findings were summarized for all studies and relevant themes summarized for qualitative and mixed methods studies.

RESULTS

A total of 47 studies were included in this review. Most studies were cross sectional (93.6%) and conducted in the United States of America (70%). Nineteen (40.4%) studies assessed the association between food choice outcomes and local retail food environment exposures, and evidence on these associations are inconclusive. Associations of certain food choice outcomes with healthy food retail environments were positive for healthy foods (in 11 studies) and unhealthy foods (in 3 studies). Associations of certain food choice outcomes with unhealthy retail food environment exposures were positive for unhealthy foods in 1 study and negative for healthy foods in 3 studies. In 9 studies, some of the food choice outcomes were not associated with retail food environment exposures. A healthy food store type and lower food prices were found to be major facilitators for healthy food access in resource-poor communities, while cost and transportation were the main barriers.

CONCLUSIONS

More research is needed on the local retail food environment in communities in low- and middle-income countries to develop better interventions to improve food choices and access to healthy foods in resource-poor communities.

Socioeconomic position and the effect of energy labelling on consumer behaviour: a systematic review and meta-analysis

BACKGROUND

There are well documented socioeconomic disparities in diet quality and obesity. Menu energy labelling is a public health policy designed to improve diet and reduce obesity. However, it is unclear whether the impact energy labelling has on consumer behaviour is socially equitable or differs based on socioeconomic position (SEP).

METHODS

Systematic review and meta-analysis of experimental (between-subjects) and pre-post implementation field studies examining the impact of menu energy labelling on energy content of food and/or drink selections in higher vs. lower SEP groups.

RESULTS

Seventeen studies were eligible for inclusion. Meta-analyses of 13 experimental studies that predominantly examined hypothetical food and drink choices showed that energy labelling tended to be associated with a small reduction in energy content of selections that did not differ based on participant SEP (X2(1) = 0.26, p = .610). Effect estimates for higher SEP SMD = 0.067 [95% CI: -0.092 to 0.226] and lower SEP SMD = 0.115 [95% CI: -0.006 to 0.237] were similar. A meta-analysis of 3 pre-post implementation studies of energy labelling in the real world showed that the effect energy labelling had on consumer behaviour did not significantly differ based on SEP (X2(1) = 0.22, p = .636). In higher SEP the effect was SMD = 0.032 [95% CI: -0.053 to 0.117] and in lower SEP the effect was SMD = -0.005 [95% CI: -0.051 to 0.041].

CONCLUSIONS

Overall there was no convincing evidence that the effect energy labelling has on consumer behaviour significantly differs based on SEP. Further research examining multiple indicators of SEP and quantifying the long-term effects of energy labelling on consumer behaviour in real-world settings is now required.

REVIEW REGISTRATION

Registered on PROSPERO (CRD42022312532) and OSF ( https://doi.org/10.17605/OSF.IO/W7RDB ).

Protocol for a novel sodium and blood pressure reduction intervention targeting online grocery shoppers with hypertension - the SaltSwitch Online Grocery Shopping randomized trial

BACKGROUND

High dietary sodium intake is a leading cause of hypertension. A major source of dietary sodium is salt added to processed food products available in retail food environments. The fast-growing online grocery shopping setting provides new opportunities for salt reduction interventions that support consumers in choosing healthier options.

METHODS

The SaltSwitch Online Grocery Shopping randomized controlled trial is investigating the feasibility, acceptability, and effectiveness of a novel intervention for lowering salt consumption and blood pressure amongst people with hypertension who shop for groceries online. The intervention is based on a bespoke web browser extension that interfaces with a major retailer's online store to highlight and interpret product sodium content and suggest similar but lower-sodium alternatives. The primary outcome of interest is change in mean systolic blood pressure between individuals randomized (1:1) to the intervention and control (usual online shopping) arms at 12 weeks. Secondary outcomes are diastolic blood pressure, spot urinary sodium and sodium:potassium ratio, sodium purchases, and dietary intake. Intervention implementation and lessons for future uptake will be assessed using a mixed methods process evaluation. Participants with hypertension who shop online for groceries and exhibit high sodium purchasing behavior are being recruited across Australia. A target sample size of 1,966 provides 80% power (2-sided alpha = 0.05) to detect a 2 mm Hg difference in systolic blood pressure between groups, assuming a 15 mm Hg standard deviation, after allowing for a 10% dropout rate.

DISCUSSION

This trial will provide evidence on an innovative intervention to potentially reduce salt intake and blood pressure in people with hypertension. The intervention caters to individual preferences by encouraging sustainable switches to similar but lower-salt products. If effective, the intervention will be readily scalable at low cost by interfacing with existing online retail environments.

Is altering the availability of healthier vs. less-healthy options effective across socioeconomic groups? A mega-analysis

Background

Availability interventions have been hypothesised to make limited demands on conscious processes and, as a result, to be less likely to generate health inequalities than cognitively-oriented interventions. Here we synthesise existing evidence to examine whether the impact of altering the availability of healthier vs. less-healthy options differs by socioeconomic position.

Methods

Individual-level data (21,360 observations from 7,375 participants) from six studies (conducted online (n = 4) and in laboratories (n = 2)) were pooled for mega-analysis. Multilevel logistic regressions analysed the impact of altering the availability of healthier options on selection of a healthier (rather than a less-healthy) option by socioeconomic position, assessed by (a) education and (b) income.

Results

Participants had over threefold higher odds of selecting a healthier option when the available range was predominantly healthier compared to selections when the range offered was predominantly less-healthy (odds ratio (OR): 3.8; 95%CIs: 3.5, 4.1). Less educated participants were less likely to select healthier options in each availability condition (ORs: 0.75–0.85; all p < 0.005), but there was no evidence of differences in healthier option selection by income. Compared to selections when the range offered was predominantly less-healthy, when predominantly healthier options were available there was a 31% increase in selecting healthier options for the most educated group vs 27% for the least educated. This modest degree of increased responsiveness in the most educated group appeared only to occur when healthier options were predominant. There was no evidence of any differential response to the intervention by income.

Conclusion

Increasing the proportion of healthier options available increases the selection of healthier options across socioeconomic positions. Availability interventions may have a slightly larger beneficial effect on those with the highest levels of education in settings when healthier options predominate.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01315-y.

Relation between the food environment and oral health-systematic review

Background

There is increasing evidence that the food environment, i.e. the availability, accessibility, price and promotion of foods and beverages, has a significant influence on oral health through food consumption. With this systematic literature review, we systematically summarize the available evidence on relations between the food environment and oral health outcomes in children and adults.

Methods

English-language studies were identified through a systematic literature search, executed by a medical information specialist, on OVID/Medline, Embase, Web of Science and CINAHL. Title and abstract screening, full-text screening and quality assessment [using the Quality Assessment with Diverse Studies (QuADS) tool] were done independently by two authors.

Results

Twenty-three studies were included, of which 1 studied the consumer food environment (food labeling), 3 the community food environment (e.g. number of food stores in the community), 5 the organizational food environment (availability of healthy foods and beverages in schools), 2 the information environment (television advertisements) and 13 government and industry policies related to the food environment (e.g. implementation of a sugar-sweetened beverage tax). Almost all studies found that unhealthy food and beverage environments had adverse effects on oral health, and that policies improving the healthiness of food and beverage environments improved—or would improve in case of a modeling study—oral health.

Conclusions

This systematic literature review provides evidence, although of low to moderate quality and available in a low quantity only, that several aspects of the food environment, especially policies affecting the food environment, are associated with oral health outcomes.

Less meat in the shopping basket. The effect on meat purchases of higher prices, an information nudge and the combination: a randomised controlled trial

Background

Reduced meat consumption benefits human and planetary health. Modelling studies have demonstrated the significant health and environmental gains that could be achieved through fiscal measures targeting meat. Adding other interventions may enhance the effect of a fiscal measure. The current study aimed to examine the effect of higher meat prices, an information nudge and a combination of both measures on meat purchases in a three-dimensional virtual supermarket.

Methods

A parallel designed randomised controlled trial with four conditions was performed. Participants (≥ 18 years) were randomly assigned to the control condition or one of the experimental conditions: a 30% price increase for meat (‘Price condition’), an information nudge about the environmental impact of meat production and consumers’ role in that regard (‘Information nudge condition’) or a combination of both (‘Combination condition’). Participants were asked to shop for their household for one week. The primary outcome was the difference in the total amount of meat purchased in grams per household per week.

Results

Between 22 June 2020 and 28 August 2020, participants were recruited and randomly assigned to the control and experimental conditions. The final sample included 533 participants. In the ‘Combination condition’, − 386 g (95% CI: − 579, − 193) meat was purchased compared with the ‘Control condition’. Compared to the ‘Control condition’ less meat was purchased in the ‘Price condition’ (− 144 g (95%CI: − 331, 43)), although not statistically significant, whereas a similar amount of meat was purchased in the ‘Information nudge condition’ (1 g (95%CI: − 188, 189)).

Conclusion

Achieving the most pronounced effects on reduced meat purchases will require a policy mixture of pricing and informational nudging. Less meat is purchased in a virtual supermarket after raising the meat price by 30% combined with an information nudge. The results could be used to design evidence-based policy measures to reduce meat purchases.

Trial registration

The trial was registered in the Netherlands Trial Register identifier NL8628. Registered on 18/05/2020. ICTRP Search Portal (who.int) NTR (trialregister.nl).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13535-9.

Impact of increasing the relative availability of meat-free options on food selection: two natural field experiments and an online randomised trial

BACKGROUND

Increasing the availability of lower energy-density foods is a promising intervention to encourage healthier food purchasing but few studies have examined the effect of increasing availability of meat-free meals to promote more sustainable purchasing. We report three studies, all examining the impact of altering the availability of meat-free meals on meal selection.

METHODS

Study 1 (a natural experiment in one university cafeteria) examined the impact of altering the ratio of meat-free meals (one meat-free and two meat, to two meat-free and one meat) on weekly sales of meals containing meat. Study 2 (a natural experiment in 18 worksite cafeterias) examined the impact on meat-free meal sales of a menu change designed to increase the availability of meat-free meals. Study 3 (an online study of 2205 UK-representative adults) compared meal selections when participants were randomised to ranges comprised of (a) one meat-free, three meat options; (b) two meat-free, two meat; or (c) three meat-free, one meat.

RESULTS

Study 1 suggested a significant decrease in the proportion of sales of meat options when the availability of meat-free options increased (- 19.9 percentage points; 95%CIs:-25.2,-14.6), with no evidence of changes to meat-based meal sales in other university cafeterias during the same period. Findings from Study 2 were mixed: multilevel regressions found no evidence of an increase in meat-free meals following the menu change (2.3 percentage points; 95%CIs: - 1.3,5.9), while interrupted time-series analyses suggested sales did increase (2.3; 95%CIs: 0.4,4.2), but implementation of the planned change was limited. In Study 3 reducing meat-free options from 50 to 25% reduced participants' selection of meat-free options (odds ratio 0.35; 95%CIs: 0.26,0.46), while increasing meat-free options from 50 to 75% increased meat-free selections (odds ratio 2.43; 95%CIs: 1.94,3.04). There was no evidence effects were moderated by gender, socioeconomic status or usual meat consumption.

CONCLUSION

Increasing the availability of meat-free options is effective at reducing meat selection and purchasing for different ratios of meat to meat-free options. The magnitude of the effect is uncertain, but with no evidence of differences in response by demographic groups when directly tested.

TRIAL REGISTRATION

Study 3: Open Science Framework; https://osf.io/ze9c6 ; 6/8/2020.

Nudging customers towards healthier food and beverage purchases in a real-life online supermarket: a multi-arm randomized controlled trial

BACKGROUND

Nudging is increasingly used to promote healthy food choices in supermarkets. Ordering groceries online is gaining in popularity and nudging seems efficacious there as well, but is never comprehensively tested in real-life. We evaluated the real-life effectiveness of nudging in an online supermarket on healthy food purchases.

METHODS

We conducted a multi-arm, parallel-group, individually randomized controlled trial in an online supermarket. During 1 month, all customers were randomized to (1) control condition, (2) information nudges, (3) position nudges, and (4) information and position nudges combined. Allocation was concealed and customers were not blinded, but unaware of the intervention. Mean differences between the control condition and the intervention arms in the total percentage of healthy purchases were assessed with a linear mixed model. We tested for effect modification by area-level deprivation.

RESULTS

Based on sales data from 11,775 shoppers, no overall significant effects were detected. Yet, effects were modified by area-level deprivation (pArm 2 < 0.001). Among shoppers from deprived areas, those allocated to information nudges purchased a 2.4% (95%CI 0.8, 4.0) higher percentage of healthy products compared to controls. No significant differences were observed for position (- 1.3%; 95%CI - 2.8, 0.3) and combined nudges (- 0.1%; 95%CI - 1.7, 1.5). Shoppers from non-deprived areas exposed to information nudges (- 1.6%; 95%CI - 3.2, - 0.1) and the combined nudges (- 2.1%; 95%CI - 3.6, - 0.6), but not position nudges (- 0.9%; 95%CI - 2.4, 0.7), purchased a lower percentage of healthy products.

CONCLUSION

Information nudges in an online supermarket can increase healthy product purchases, but only for those living in deprived areas. The adverse effects found on purchasing behaviors for those from non-deprived areas call for further research. Further research should also focus on real-life effects of online healthy food nudging as part of a broader nutrition intervention strategy, and on the equitability of the online nudging intervention within populations.

TRIAL REGISTRATION

Retrospectively registered in the ISRCTN registry at May 21, 2021 ( ISRCTN10491616 ).

A Proposed Research Agenda for Promoting Healthy Retail Food Environments in the East Asia-Pacific Region

PURPOSE OF REVIEW

This paper aimed to summarise existing literature on strategies to improve the healthiness of retail food environments in the East Asia and Pacific (EAP) region, and propose a prioritised research agenda on this topic.

RECENT FINDINGS

Little research on retail food environments has been conducted in the EAP region. Several approaches for measuring retail food environments were identified, although none have been tailored to the EAP context. A small number of policies and initiatives to promote healthy retail food environments have been implemented in EAP. Lessons learnt from successful implementation of initiatives in other regions could be applied in EAP. Retail food environments have a strong influence on food choices and health outcomes. Research can contribute to efforts to improve the healthiness of retail food environments in EAP by (1) describing the current state of retail food environments to highlight areas of good practice and concern and (2) identifying policies and initiatives that are likely to be effective, and mechanisms for their successful implementation.

Are nudging and pricing strategies on food purchasing behaviors equally effective for all? Secondary analyses from the Supreme Nudge virtual supermarket study

Nudging and pricing strategies are effective in promoting healthier purchases. However, whether the effects are equal across individuals with different personal characteristics is unknown. This exploratory study aimed to examine differential effects of nudging and pricing strategies on food purchases across individuals' levels of impulsivity, price sensitivity, decision-making styles, and food choice motives. Data from a virtual supermarket experiment where participants were exposed to five study conditions (control, nudging, pricing, salient pricing, and salient pricing with nudging) was used. Participants completed questionnaires assessing their impulsivity, price sensitivity, decision-making styles, and food choice motives. The outcome was the percentage of healthy food purchases. Effect modification was analyzed by adding interaction terms to the statistical models and post-hoc probing was conducted for statistically significant interaction terms. We used data from 400 Dutch adult participants (61.3% female, median age 30.0 years (IQR 24.0)). The effects of the nudging and pricing conditions on healthy food purchases were not modified by impulsivity, price sensitivity, decision-making styles, and the food choice motives 'health' and 'price'. Only the interactions of the food choice motive 'natural content of foods' x pricing (B = -1.02, 90%CI = -2.04; -0.01), the food choice motive 'weight control' x nudging (B = -2.15, 90%CI = -3.34; -0.95), and 'weight control' x pricing (B = -1.87, 90%CI = -3.11; -0.62) were statistically significant. Post-hoc probing indicated that nudging and/or pricing strategies were more effective in individuals who gave lower priority to these food choice motives. The effects of nudging and pricing strategies on increasing healthy food purchasing behaviors, at least in a virtual environment, do not seem to be influenced by personal characteristics and may therefore be implemented as general health promoting strategies.

An appeal to our government for nationwide policies in the prevention of cardiovascular disease

The high prevalence and burden of cardiovascular diseases (CVD) is largely attributable to unhealthy lifestyle factors such as smoking, alcohol consumption, physical inactivity and unhealthy food habits. Prevention of CVD, through the promotion of healthy lifestyles, appears to be a Sisyphean task for healthcare professionals, as the root causes of an unhealthy lifestyle lie largely outside their scope. Since most lifestyle choices are habitual and a response to environmental cues, rather than rational and deliberate choices, nationwide policies targeting the context in which lifestyle behaviours occur may be highly effective in the prevention of CVD. In this point-of-view article, we emphasise the need for government policies beyond those mentioned in the National Prevention Agreement in the Netherlands to effectively reduce the CVD risk, and we address the commonly raised concerns regarding ‘paternalism’.

Systematic review of clinician-directed nudges in healthcare contexts

OBJECTIVE

Nudges are interventions that alter the way options are presented, enabling individuals to more easily select the best option. Health systems and researchers have tested nudges to shape clinician decision-making with the aim of improving healthcare service delivery. We aimed to systematically study the use and effectiveness of nudges designed to improve clinicians' decisions in healthcare settings.

DESIGN

A systematic review was conducted to collect and consolidate results from studies testing nudges and to determine whether nudges directed at improving clinical decisions in healthcare settings across clinician types were effective. We systematically searched seven databases (EBSCO MegaFILE, EconLit, Embase, PsycINFO, PubMed, Scopus and Web of Science) and used a snowball sampling technique to identify peer-reviewed published studies available between 1 January 1984 and 22 April 2020. Eligible studies were critically appraised and narratively synthesised. We categorised nudges according to a taxonomy derived from the Nuffield Council on Bioethics. Included studies were appraised using the Cochrane Risk of Bias Assessment Tool.

RESULTS

We screened 3608 studies and 39 studies met our criteria. The majority of the studies (90%) were conducted in the USA and 36% were randomised controlled trials. The most commonly studied nudge intervention (46%) framed information for clinicians, often through peer comparison feedback. Nudges that guided clinical decisions through default options or by enabling choice were also frequently studied (31%). Information framing, default and enabling choice nudges showed promise, whereas the effectiveness of other nudge types was mixed. Given the inclusion of non-experimental designs, only a small portion of studies were at minimal risk of bias (33%) across all Cochrane criteria.

CONCLUSIONS

Nudges that frame information, change default options or enable choice are frequently studied and show promise in improving clinical decision-making. Future work should examine how nudges compare to non-nudge interventions (eg, policy interventions) in improving healthcare.

Determinants of Food Choice and Perceptions of Supermarket-Based Nudging Interventions among Adults with Low Socioeconomic Position: The SUPREME NUDGE Project

Nudging has received ample attention in scientific literature as an environmental strategy to promote healthy diets, and may be effective for reaching populations with low socioeconomic position (SEP). Therefore, the objective of this study was to investigate how the determinants of food choice shape the perceptions regarding supermarket-based nudging strategies among adults with low SEP. We conducted semi-structured interviews among fifteen adults with low SEP using a pre-defined topic list and visual examples of nudges. Interviews were recorded and transcribed verbatim and content analysis was used to analyse the data. The results show that food costs, convenience, healthiness, taste, and habits were frequently mentioned as determinants of food choice. However, the relative importance of these determinants seemed to be context-dependent. Interviewees generally had a positive attitude towards nudges, especially when they were aligned with product preferences, information needs, and beliefs about the food environment. Still, some interviewees also expressed distrust towards nudging strategies, suspecting ulterior motives. We conclude that nudging strategies should target foods which align with product preferences and information needs. However, the suspicion of ulterior motives highlights an important concern which should be considered when implementing supermarket-based nudging strategies.

Shifting toward a healthier dietary pattern through nudging and pricing strategies: A secondary analysis of a randomized virtual supermarket experiment

BACKGROUND

Nudging and salient pricing are promising strategies to promote healthy food purchases, but it is possible their effects differ across food groups.

OBJECTIVE

To investigate in which food groups nudging and/or pricing strategies most effectively changed product purchases and resulted in within-food groups substitutions or spillover effects.

METHODS

In total, 318 participants successfully completed a web-based virtual supermarket experiment in the Netherlands. We conducted a secondary analysis of a mixed randomized experiment consisting of 5 conditions (within subject) and 3 arms (between subject) to investigate the single and combined effects of nudging (e.g., making healthy products salient), taxes (25% price increase), and/or subsidies (25% price decrease) across food groups (fruit and vegetables, grains, dairy, protein products, fats, beverages, snacks, and other foods). Generalized linear mixed models were used to estimate the incidence rate ratios and 95% CIs for changes in the number of products purchased.

RESULTS

Compared with the control condition, the combination of subsidies on healthy products and taxes on unhealthy products in the nudging and price salience condition was overall the most effective, as the number of healthy purchases from fruit and vegetables increased by 9% [incidence rate ratio (IRR) = 1.09; 95% CI: 1.02, 1.18], grains by 16% (IRR = 1.16; 95% CI: 1.05, 1.28), and dairy by 58% (IRR = 1.58; 95% CI: 1.31, 1.89), whereas the protein and beverage purchases did not significantly change. Regarding unhealthy purchases, grains decreased by 39% (IRR = 0.72; 95% CI: 0.63, 0.82) and dairy by 30% (IRR = 0.77; 95% CI: 0.68, 0.87), whereas beverage and snack purchases did not significantly change. The groups of grains and dairy showed within-food group substitution patterns toward healthier products. Beneficial spillover effects to minimally targeted food groups were seen for unhealthy proteins (IRR = 0.81; 95% CI: 0.73, 0.91).

CONCLUSIONS

Nudging and salient pricing strategies have a differential effect on purchases of a variety of food groups. The largest effects were found for dairy and grains, which may therefore be the most promising food groups to target in order to achieve healthier purchases. The randomized trial on which the current secondary analyses were based is registered in the Dutch trial registry (NTR7293; www.trialregister.nl).

Healthy eating: a matter of prioritisation by households or policymakers?

I reflect upon the potential reasons why American low-income households do not spend an optimal proportion of their food budgets on fruits and vegetables, even though this would allow them to meet the recommended levels of fruit and vegetable consumption. Other priorities than health, automatic decision-making processes and access to healthy foods play a role, but solutions for the persistent socio-economic inequalities in diet should be sought in the wider food system which promotes cheap, mass-produced foods. I argue that, ultimately, healthy eating is not a matter of prioritisation by individual households but by policymakers.