Comparing Online and In-Store Grocery Purchases.

OBJECTIVE: To describe the grocery shopping patterns of people who shopped both online and in-store and evaluate whether shoppers purchased fewer unhealthy, impulse-sensitive items online. DESIGN: Secondary analysis of 44 weeks of grocery transaction data collected for fruit and vegetable incentive trials in 2 Maine supermarkets. PARTICIPANTS: A total of 137 primary household shoppers who shopped at least once in-store and online (curbside pickup) for 5,573 total transactions MAIN OUTCOME MEASURES AND ANALYSIS: Paired t tests and descriptive analyses compared online and in-store transactions with respect to frequency, total spending, number of items purchased, and spending on 10 food groups and 34 subgroups. Mixed-effects regression models estimated differences in online vs in-store spending on 5 unhealthy, impulse-sensitive subgroups. RESULTS: When shopping online, participants spent 44% more per transaction ($113.58 vs $78.88, P < 0.001) and purchased more items (38.3 vs 26.6 items/transaction, P < 0.001). Compared with in-store, shopping online was associated with reduced spending per transaction on candy (-$0.65, P < 0.001), cold or frozen desserts (-$0.52, P < 0.001), and grain-based desserts (-$1.29, P < 0.001). CONCLUSIONS AND IMPLICATIONS: Online shopping was associated with lower spending on certain unhealthy, impulse-sensitive foods. Grocery-based healthy eating initiatives might leverage online ordering platforms to increase their reach and effectiveness.