Using the Australian Dietary Guidelines 2&5 education message in supermarket shopping trolleys to nudge shoppers to purchase more fruit and vegetables: A feasibility study using an intervention design

Fruit and vegetable (F&V) consumption is associated with a reduced risk of developing chronic diseases; however, only one in 16 Australian adults consume F&Vs at the recommended two servings of fruit and five servings of vegetables per day. What and how much people eat is influenced by their social and physical environments. Supermarkets are a key setting influencing food purchases, and as such, they can shape consumption patterns of F&Vs. Implementing effective strategies to increase F&V intake is crucial. The objective of this research was to test the feasibility of modifying shopper purchasing behaviour to purchase more F&Vs using the Australian Dietary Guidelines 2&5 education message covering one-half of the base of shopping trolleys. Placards giving the message that eating 2 fruits and 5 vegetables every day for good health were placed at the base of shopping trolleys as an educational nudge. Applying an intervention research design, 30 out of ~100 trolleys were fitted with the placards and shopper purchases were measured by collecting paper sales receipts to measure the weight (kg), total spending and F&V-specific spending (Australian dollars) for intervention versus control trolleys for one Saturday. We also conducted a short intercept survey that was administered independently from the research study day on non-trial shoppers. Shoppers who selected trolleys with the 2&5 education nudge placards (n = 101) purchased 1.66 kg less weight of F&Vs (Intervention: mean = 3.89 kg, SD = 3.40 kg, 95% CI = 3.21 kg, 4.56 kg, vs. Control: mean 5.55 kg, SD = 4.16 kg, 95% CI = 4.73 kg, 6.37 kg, p = 0.002) and spent less on F&Vs compared to shoppers in the control group (n = 102; Intervention: mean = $26.00, SD = $21.60, 95% CI = $21.78, $30.32 vs. Control: mean $36.00, SD = $27.00, 95% CI = $30.72, $42.36, p = 0.004). Intervention group shoppers also spent less in total spending between groups (Intervention: mean = $115.40, SD = $68.30, 95% CI = $101.95, $128.95 vs. Control: mean $151.30, SD = $79.40, 95% CI = $135.73, $166.93, p = 0.001). The 2&5 education nudge placard had the opposite effect as intended on shoppers' purchases to buy more F&Vs, although there may have been other differences between the intervention and the control groups since they were not randomised. Larger studies are required to elucidate and confirm these findings over the longer term.