Effects of an optimal defaults grocery shopping intervention on household grocery purchases of families with young children

Background: Implementing optimal defaults by pre-filling online grocery shopping carts with healthy ingredients has increased nutritional quality of grocery purchases among adults. The objective of this pilot trial was to test effects of an optimal defaults online grocery shopping intervention on grocery purchases among families with 2-to-5-year-old children at risk for obesity. Methods: Parents/guardians of 2-to-5-year-olds who online grocery shopped from one of three study stores were recruited for a 4-week, 2-group randomized trial and randomized to a defaults intervention or control group (n = 69). Healthy recipes were provided to all families during a 2-week intervention. The defaults group also had their online grocery carts pre-filled with recipe ingredients. Participants could modify these carts as desired. Families grocery shopped as usual during 2 baseline weeks, providing grocery purchase data via receipts; purchases were also measured during the 2 intervention weeks that followed, with nutritional quality coded using the Healthy Eating Index. Effects on nutritional quality, energy content, and cost of grocery purchases were tested across all household grocery purchases and purchases from study stores. Results: Nutritional quality of the defaults group's household grocery purchases improved significantly from baseline to intervention relative to controls (p < 0.01; 5.4 % increase vs. 8.3 % decrease). Results for study store purchases were similar but not statistically significant. Energy content of and dollars spent on groceries decreased from baseline to intervention in both groups. Conclusions: Results extend evidence supporting optimal defaults grocery interventions to families with a young child at risk for obesity, with implications for diet-related disease prevention. Trial registration: Study procedures were registered atclinicaltrials.govprior to participant enrollment (NCT05899634).