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

Online retail nudges to help parents with lower-income choose healthy beverages for their children: A randomized clinical trial

BACKGROUND

Nudges offer a promising tool to reduce sugary drink intake among children who are most at risk for diet-related disease.

OBJECTIVE

To examine the impact of online store nudges on purchases of sugary drinks for children in lower-income households.

METHODS

Caregivers with lower-income were recruited to an online shopping experiment and instructed to spend $10-$30 on three beverages for their child aged 1-5 years. Participants were randomized to navigate an online supermarket in its standard version (n = 1106) or a version with nudges (n = 1135), including a product placement nudge (i.e. placing healthy beverages in prominent positions) and a swap nudge (i.e. offering a swap of water, plain milk and/or 100% fruit juice upon selection of sugary drinks).

RESULTS

On average, participants purchased 1887 (SD = 2113) and 620 (SD = 1528) calories from sugary drinks per basket in the control and experimental conditions, respectively. Model-based results indicate that those in the experimental condition purchased 1267 (95% CI: 1419, 1114) fewer calories from sugary drinks, and fewer grams of total sugar (β = -253.5 g (95% CI: -286.3, -220.6)) and added sugar (β = -287.8 g (95% CI: -323.1, -252.5)) purchased from sugary drinks.

CONCLUSION

Nudges may be an effective, acceptable, scalable strategy for leading caregivers in lower-income households to purchase fewer sugary drinks for their children.

Impact of food swap recommendations on dietary choices in an online supermarket: A randomized controlled trial

One novel strategy to shift food choices in digital shopping environments is to automatically recommend healthier alternatives when an unhealthy choice is made. However, this raises the question which alternative products to recommend. This study assesses 1) whether healthier food swap recommendations are effective, even though the unhealthy choice was made in the presence of visible FOP nutrition labels, and 2) how the similarity of the alternatives influences the acceptance of food swap recommendations. Based on a pre-test, similarity of the recommendation was operationalized in terms of animal-based versus plant-based options. A randomized controlled trial (healthy food swap recommendation conditions: none, similar animal-based, dissimilar plant-based, or mixed animal- and plant-based) with 428 Dutch participants was conducted in a simulated online supermarket. Additional healthier food swap recommendations improved the nutritional quality of the final basket compared to only providing Nutri-Score nutrition labels (-1.7 mean FSA score, p < .001, medium Cohen's d = -0.48). Compared to the dissimilar condition, acceptance of an alternative was more likely in the mixed (odds-ratio = 2.78, p = .015) and in the similar condition (odds-ratio = 2.24, p = .048), but the nutritional quality of the final basket did not differ between treatment conditions. Individuals in treatment conditions who did not receive any recommendation (i.e. only made healthy choices) had higher Nutri-Score familiarity and general health interest than individuals who received recommendations. This suggests that for individuals with higher knowledge and motivation FOP nutrition labels were sufficient, whereas for individuals with lower knowledge and motivation additional food swap recommendations can improve dietary choices. Food swap recommendations may act as meaningful reminders by disrupting the automatic choice process and triggering individuals to rethink their (unhealthy) choice.

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.

Testing the impact of overt and covert ordering interventions on sustainable consumption choices: A randomised controlled trial

Food products have significant impacts on the environment over their life cycle. We investigated whether displaying products in ascending order of carbon footprint in an online supermarket environment can shift consumer choices towards more sustainable options. We examined whether the effect of the ordering intervention differs when the ordering is overt (information about the ordering is explicit), compared to when it is covert (participants not told about the ordering). We conducted a three-arm parallel-group randomised trial using 1842 online participants from England, Wales, and Northern Ireland. Participants shopped for a meal, choosing one product from each of six product categories in a simulated online supermarket. Six products were listed vertically on each product-category page. Products were randomly ordered for the control arm but ordered by carbon footprint in the covert and overt ordering arms. In the overt ordering arm, a statement was displayed at the top of each product page about the ordering of products. The primary outcome was whether one of the three most sustainable products was chosen in each product category. There was no effect of the covert ordering on the probability of choosing more sustainable products compared with the control arm (OR = 0.97, 95% CI 0.88-1.07, p = 0.533). Furthermore, we did not find evidence that the effects of the covert ordering and overt ordering differed (p = 0.594). Within the control condition, products in different positions were chosen with similar frequencies, suggesting that product positioning does not have an impact on choices. This may explain why re-ordering products had no effect. In the overt condition, only 19.5% of people correctly answered that the products were ordered according to sustainability in a follow-up question, suggesting that they didn't notice the statement. Results suggest that choices for grocery products might be too ingrained to be changed by subtle rearrangements of choice architecture like the ordering interventions, and highlight the difficulty of conveying information effectively to consumers in the online grocery shopping environment.

Perceptions of social norms around healthy and environmentally-friendly food choices: Linking the role of referent groups to behavior

Referent groups can moderate the perception of social norms and individuals' likelihood to model these norms in food choice contexts, including vegetable intake and reduced meat consumption. The present study investigated whether having a close vs. a distant social group as the referent changed perceptions of social norms around making healthy and eco-friendly food choices. It also assessed whether these changes were associated with a difference in the health and environmental impacts of food choice in a virtual grocery shopping task. A nationally representative sample of UK adults (N = 2,488) reported their perceptions of making healthy and eco-friendly food choices being the norm among people they share meals with (close referent group) and most people in the UK (distant referent group). The former was more commonly perceived to be making both healthy (Z = -12.0, p < 0.001) and eco-friendly (Z = -13.27, p < 0.001) food choices than the latter. Perceptions of norms referring to the close group were significantly associated with the environmental (β = -0.90, 95% CIs: -1.49, -0.28) and health (β = -0.38 p < 0.05, 95% CIs: -0.68, -0.08) impacts of participants' food choices in a virtual shopping task. No such relationship was found for norms referring to the distant group for both environmental (β =0.43, p > 0.05, 95% CIs: -1.12, 0.25) and health (β = -0.06, p > 0.05, 95% CIs: -0.37, 0.25) impacts. Framing social norms around making healthy and eco-friendly food choices to refer to a close referent group may change their perceptions and ability to encourage sustainable and healthy food purchasing.