Encouraging healthier grocery purchases online: A randomised controlled trial and lessons learned

Abstract

Online supermarket platforms present an opportunity for encouraging healthier consumer purchases. A parallel, double‐blind randomised controlled trial tested whether promoting healthier products (e.g. lower fat and lower calorie) on the Sainsbury's online supermarket platform would increase purchases of those products. Participants were Nectar loyalty membership scheme cardholders who shopped online with Sainsbury's between 20th September and 10th October 2017. Intervention arm customers saw advertisement banners and recipe ingredient lists containing healthier versions of the products presented in control arm banners and ingredient lists. The primary outcome measure was purchases of healthier products. Additional outcome measures were banner clicks, purchases of standard products, overall purchases and energy (kcal) purchased. Sample sizes were small due to customers navigating the website differently than expected. The intervention encouraged purchases of some promoted healthier products (spaghetti [B = 2.10, p < 0.001], spaghetti sauce [B = 2.06, p < 0.001], spaghetti cheese [B = 2.45, p = 0.001], sour cream [B = 2.52, p < 0.001], fajita wraps [B = 2.10, p < 0.001], fajita cheese [B = 1.19, p < 0.001], bakery aisle products (B = 3.05, p = 0.003) and cola aisle products [B = 0.97, p < 0.002]) but not others (spaghetti mince, or products in the yogurt and ice cream aisles). There was little evidence of effects on banner clicks and energy purchased. Small sample sizes may affect the robustness of these findings. We discuss the benefits of collaborating to share expertise and implement a trial in a live commercial environment, alongside key learnings for future collaborative research in similar contexts.

A Systematic Review of Marketing Practices Used in Online Grocery Shopping: Implications for WIC Online Ordering

“…Of these articles, 18 met the inclusion criteria and were included for data extraction and evidence synthesis, see Table 2 . Of the eighteen articles, nine studies were randomized controlled trials [ 46 , 49 , 50 , 51 , 52 , 54 , 55 , 56 , 59 ]. Another seven [ 44 , 45 , 47 , 48 , 53 , 57 , 60 ] were observational studies that primarily used quasi-experimental methodologies such as analyzing retail scanner data to follow the behavior of shoppers over time.…”

“…The included studies listed in Table 2 were all published between 2015 and 2022. Studies were conducted in Belgium [ 49 ], Denmark [ 56 ], Iceland [ 58 ], Iran [ 59 ], the Netherlands [ 52 ], Spain [ 44 ], the United Kingdom [ 45 , 46 , 48 , 50 , 54 , 55 ], the United States [ 53 , 57 , 60 ], and multiple or unspecified European countries [ 24 , 47 , 51 ].…”

“…For instance, Forwood et al recruited a nationally representative sample of adult participants in the U.K. for their study [ 50 ], whereas De Bauw et al targeted “food decision makers” in Belgian households [ 49 ]. Studies using retail scanner data or household loyalty card data sometimes did not explicitly state that they restricted their analyses to adult shoppers or certain types of households but often restricted to households who made certain numbers of online or in-store purchases [ 44 , 45 , 46 , 47 ]. Several studies conducted subgroup analyses, but no studies we identified were specifically targeted at the WIC population or populations that could be inferred to be WIC or WIC-eligible populations, such as mothers of young children living in households with low incomes.…”

“…For example, recommender models may be used to expose shoppers to products through advertisement banners and recipes. In Bunten et al, shoppers who were exposed to advertisement banners and recipes that used healthier products purchased more of the promoted healthier items [ 46 ].…”

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

“…It is worth pointing out that, the trial simplified many of the real-life considerations. In a real online supermarket, consumers can go straight to the lists of their favourite products or products they have bought before and choose from there, without being exposed at all to other products that might be more sustainable (Bunten et al, 2022).…”