Efficacy of supermarket and web-based interventions for improving dietary quality: a randomized, controlled trial

Dietary interventions may best be delivered at supermarkets, which offer convenience, accessibility, full food inventories and, increasingly, in-store registered dietitians, online shopping and delivery services. In collaboration with a large retail supermarket chain, we conducted a multisite supermarket and web-based intervention targeting nutrition trial (no. NCT03895580), randomizing participants ( n = 247 (139 women and 108 men)) 2:2:1 to two levels of dietary education (Strategy 1 and Strategy 2) or an enhanced control group that included educational components beyond the routine standard of care. Both Strategies 1 and 2 included individualized, in-person, dietitian-led, purchasing data-guided interventions. Strategy 2 also included online tools for shopping, home delivery, selection of healthier purchases, meal planning and healthy recipes. The primary endpoint was change in dietary approaches to stop hypertension (DASH) score (a measure of adherence to the DASH diet) from baseline to 3 months. The primary endpoint was met because, at 3 months, the DASH score increased by 4.7 more for the combined Strategy 1 and Strategy 2 groups than for the control group (95% confidence interval (CI) (0.9, 8.5), P = 0.02). In a prespecified hierarchical test, at 3 months, DASH score increased by 3.8 more for the Strategy 2 group than for the Strategy 1 group (95% CI (0.8, 6.9), P = 0.01). This trial demonstrates the efficacy of data-guided, supermarket-based, dietary interventions and modern online shopping tools in improving dietary quality in a free-living, community-based population. The trial also demonstrates the opportunity for academic investigators to collaborate with retailers to design and rigorously test comprehensive healthcare interventions.