Defaults group measures
Research staff and participants both had access to the participants’ online grocery shopping accounts. Participants’ financial information was encrypted and inaccessible to research staff, but they had access to all other functionality and would use the shared account to prepopulate a grocery cart with default items that aligned with the DASH diet and study recipes for each week. Four to nine default ingredients were added to the participants’ carts each week.For a measure of intervention integrity, participants in the Defaults group were asked if they saw the prefilled carts in the online grocery shopping platform (yes/no) in the exit survey. To measure intervention acceptance and appropriateness, exit surveys included an item on whether Defaults participants found the prefilled carts to be useful (not useful at all, somewhat useful, very useful). Research assistants independently double-coded the food receipt data to determine if the Defaults group purchased none (0), some (1) or all (2) of the default items placed into their online shopping carts. For an item to be considered an accepted default, the item had to be accepted exactly as is without modification. For example, if a participant substituted a 16-oz orange juice for a 64-oz orange juice, it was not considered an acceptance of the default, given the participant would have made a modification. Once research assistants coded the receipts, discrepancies were reconciled by a third reviewer, and proportions were calculated to determine the percentage of the sample purchasing none, some or all default items placed into the online shopping carts by week and by recipe. We also evaluated willingness to use prefilled grocery shopping carts in the future (yes/no).