Discussion
diabetes
TYPE 2 DIABETES, SHOP, DIABETES
Findings from this study suggest that it was feasible to implement an optimal defaults intervention to improve the nutritional quality of grocery purchases for people with or at-risk for diabetesFifty-five (83 %) of our participants had complete protocol adherence, including submitting receipts across all study weeks. A strength of this study is the high rate of participant compliance and retention, though findings should be replicated in longer, larger studies. A systematic review of 174 longitudinal cohort studies reported that ‘flexibility in data collection methods might be most effective in maximizing retention’A limitation of this study is the homogeneity of the sample, which is predominantly white and college educated. There are several ways to open eligibility criteria in the future to improve heterogeneity. Given that 25 % of people that completed the eligibility screener were excluded for not shopping at one of the study stores, future research could modify or extend the stores that are included, with an eye towards stores in under-resourced neighbourhoods. In the present study, two of the largest grocery chains in the researchers’ geographic area were selected as study stores, to broaden external validity to the extent possible for a pilot study. That decision also helped with the feasibility of filling default grocery shopping carts. Since the design of this study, additional grocery stores are available on the online grocery platform used in this study, offering the potential to include other study stores in the future.In addition, 134 people that completed the eligibility screener were excluded for receiving SNAP/WIC benefits. At the time this study was designed, the grocery platform used for this study did not accept electronic benefits as a form of payment and therefore the research team did not want to recruit participants that may not be able to shop online. Since then, SNAP purchasing pilots have expanded, and many retailers are approved to accept SNAP onlineFood purchases are an antecedent to food consumption and are strongly correlated with diet qualityAbout 65 % of participants used study recipes, with greater usage in the Defaults group, in which 86 % reported using recipes. Nutrition and cooking education is a widely used strategy to improve dietary outcomes for people with or at-risk for diabetes and one of the best known examples is the diabetes prevention programMost participants in the Defaults group accepted at least one of the ingredients in the default carts each week (82–95 %) which also suggests that the intervention may be acceptable to participants. Out of the standard recipes, acceptance was highest for whole grain pasta and grilled chicken, chicken quesadillas and grilled chicken and olives. Researchers interested in conducting a similar study could use the study recipes most liked by participants (Table Most participants in the Online and Defaults groups were compliant and shopped online, though some continued to supplement online shopping with in-person shopping, and not all participants liked shopping online. One participant dropped out of the study because they did not want to shop online, and of those who shopped online during the study, 28 % indicated they did not plan to shop online in the future. While online grocery shopping is expected to continue to growThe most frequent complaint from participants was challenges with the food receipt form, the tool used to collect food purchasing details that may not be included on a receipt (e.g. product weight, size, quantity or brand). Potential solutions could include partnering with an online platform to see the exact product(s) participants purchased or using food tracking or grocery shopping applications that allow participants to scan barcodes and create food diaries or shopping lists from their purchases, which may be more user-friendly. This study highlights the need for technological and practical advancements that improve the process of collecting purchasing data from participants and reduce the time it takes for study staff to conduct nutritional analysis of receipt data, not just for studies of grocery defaults, but to benefit the broader food purchasing literature.In this pilot randomised controlled trial, we found that an optimal defaults intervention aiming to improve grocery purchases using prefilled default grocery carts is an acceptable, feasible and desirable intervention for many people with or at-risk for type 2 diabetes. Using the lessons learned from this study, extension of this research may include expanding inclusion criteria to recruit a more heterogeneous sample, providing participants with more recipe options, prepopulating default carts with items that may be more desirable to participants and members of their household and streamlining the process for collecting detailed receipt data. Future research could increase the study period beyond 5 weeks to identify whether compliance and retention remain high over longer periods of time and whether long-term dietary change is possible. Implementing recommendations identified in this pilot study may increase the likelihood of continued adherence to the study protocol and defaults recommendations.