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

Strategies associated with improved healthiness of consumer purchasing in supermarket interventions: a systematic overview of reviews and evaluation of primary articles

Background

Growing evidence suggests that it is possible to change the retail food environment to enable healthier choices via in-store interventions. It has been difficult to draw clear conclusions as to which interventions are most effective in positively influencing consumer purchasing behaviour given the significant heterogeneity within the food retail research literature. The aim of this study was to (1) summarise current high-quality systematic, scoping, and/or narrative reviews (Part I: overview of reviews); and (2) synthesise high-quality original research, to understand the range, types and effectiveness of strategies implemented in food retail settings (Part II: evaluation of primary studies).

Methods

To identify reviews describing the effects of intervention strategies aiming to improve the healthiness of consumer purchasing in supermarkets, a systematic search across seven electronic databases was completed in April 2023. The methodological quality of reviews was assessed using the risk of bias in systematic reviews for systematic and scoping reviews, and the Scale for the Assessment of Narrative Review Articles for narrative reviews. High-quality reviews were further inspected and synthesised narratively (Part I). Next, to understand strategies associated with improved healthiness of consumer purchasing high-quality, primary articles from high-quality reviews identified in Part I were retrieved, and the strategies implemented within these interventions were summarised (Part II).

Results

Thirty-eight reviews met the inclusion criteria for Part I; two-thirds (n = 25, 66%) were rated as high-quality (66%). These reviews indicated that pricing strategies had the greatest proportion of reported positive or promising effects on outcomes (n = 8 of 11 reviews, 73%). Twenty reviews met the inclusion criteria for Part II and the 771 primary articles from these reviews were screened with 23 high-quality primary articles included in analysis. Findings indicated that promotional strategies in combination with another strategy appeared to be most successful among regular shoppers (the general population), whereas pricing was most successful in low socio-economic status and rural sub-groups.

Conclusion

Promotion, pricing and prompting were the most commonly tested strategies across the overview of reviews and review of primary articles. Promotion, in combination with other strategies, and pricing appear to be most promising, but the effectiveness of pricing strategies may vary by sub-groups of the population. How pricing and promotion in combination with other strategies can be implemented responsibly and sustainably to change purchase habits towards healthier items should be explored further.

Systematic Review registration

OSF, https://osf.io/jyg73/.

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.

Changing the default order of food items in an online grocery store may nudge healthier food choices

Restructuring food environments, such as online grocery stores, has the potential to improve consumer health by encouraging healthier food choices. The aim of this study was to investigate whether repositioning foods within an experimental online grocery store can be used to nudge healthier choices. Specifically, we investigated whether repositioning product categories displayed on the website main page, and repositioning individual products within those categories, will influence selection. Adults residing in Australia (n = 175) were randomised to either intervention (high-fibre foods on top) or comparator condition (high-fibre foods on the bottom). Participants completed a shopping task using the experimental online grocery store, with a budget of up to AU$100 to for one person's weekly groceries. The results of this study show that the total fibre content per 100 kcal per cart (p < .001) and total fibre content per cart (p = .036) was higher in the intervention compared to comparator condition. Moreover, no statistical difference between conditions was found for the total number of fibre-source foods (p = .67), the total energy per cart (p = .17), and the total grocery price per cart (p = .70) indicating no evidence of implications for affordability. Approximately half of the participants (48%) reported that they would like to have the option to sort foods based on a specific nutrient criterion when shopping online. This study specifically showed that presenting higher-fibre products and product categories higher up on the online grocery store can increase the fibre content of customers' purchases. These findings have important implications for consumers, digital platform operators, researchers in health and food domains, and for policy makers.

Unhealthy food availability, prominence and promotion in a representative sample of supermarkets in Flanders (Belgium): a detailed assessment

INTRODUCTION

The supermarket food environment is a key setting for potential public health interventions. This study assessed food availability, prominence and promotion in a representative sample of supermarkets in Flanders (Belgium).

METHODS

A sample of 55 supermarkets across five chains and 16 Flemish municipalities was selected in 2022, about 64% in the most deprived socioeconomic areas. Healthiness indicators related to food availability (ratio of cumulative linear shelf length for healthy versus unhealthy foods), prominence (proportion of unhealthy foods at check-outs and end-of-aisle endcaps), and promotion (food marketing on food packages) were measured.

RESULTS

Overall, the average ratio of healthy/unhealthy foods in supermarkets in Flanders was 0.36, meaning that for every 10m of shelf length of unhealthy foods there was 3.6m of healthy foods. There was a large variation in ratio's across supermarket chains. Of all foods available, 97.5% were ultra-processed at the check outs, while 72.2% and 58.5% were ultra-processed at the front and back end-of-aisle end-caps, respectively. Confectionery and sweet biscuits were the food categories with on average the highest number of marketing messages on pack per 10m of shelf length.

CONCLUSION

Supermarket in-store food environments in Flanders were found generally unhealthy, with those located in low income areas having unhealthier in-store food environments than supermarkets located in medium and high income areas. Despite commitments of all large supermarket chains in Flanders to promote and create healthier in-store food environments, our findings indicate that currently consumers are incentivized to buy unhealthy rather than healthy food products.

Evaluating the impact of marketing interventions on sugar-free and sugar-sweetened soft drink sales and sugar purchases in a fast-food restaurant setting

BACKGROUND

Beverages high in added sugar, such as sugar-sweetened soft drinks, continue to be associated with various health issues. This study examines the effects of a manufacturer-initiated multicomponent intervention on the sales of sugar-free (SFD) and sugar-sweetened (SSD) soft drinks and the amount of sugar people purchase from soft drinks in a fast-food restaurant setting.

METHODS

A database of monthly sales data of soft drinks from January 2016 to December 2018 was obtained from three treatment and three control fast-food restaurants. A multicomponent intervention consisting of free coupons, point-of-purchase displays, a menu board, and two sugar-free replacements for sugar-sweetened soft drinks was introduced in August 2018 for five months in Western Sydney, Australia. A retrospective interrupted time series analysis was used to model the data and examine the effects of the interventions on SFD and SSD sales and their consequential impact on sugar purchases from soft drinks. The analyses were carried out for volume sales in litres and sugar in grams per millilitre of soft drinks sales. A comparison of these measures within the treatment site (pre- and post-intervention) and between sites (treatment and control) was conducted.

RESULTS

The interventions had a statistically significant impact on SFDs but not SSDs. On average, SFD sales in the treatment site were 56.75% higher than in the control site. Although SSD sales were lower in the treatment site, the difference with the control site was not statistically significant. The net reduction of 6.34% in the amount of sugar purchased from soft drinks between sites during the experimental period was attributed to the interventions.

CONCLUSIONS

The interventions significantly increased SFD sales and reduced sugar purchases in the short run. Aside from free coupons, the findings support the recommendation for fast food restaurants to nudge customers towards choosing SFDs through point-of-purchase displays and the replacement of popular SSDs with their SFD counterparts.

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.