CTSI Pilot: improving Adherence to Diabetic Diet

The goal of this study is to test the effects of interventions informed by behavioral economics on the healthfulness of grocery purchases among diabetic adults. This study has a 3‐group experimental design; adult patients with diabetes or at risk for diabetes who typically grocery shop in‐person will be randomly assigned to one of two interventions or a control group. In all groups, recipe cards that follow the evidence‐based DASH diet and correspond to dietary recommendations for diabetic patients will be provided. In addition, the first intervention, Online, will utilize online grocery shopping at a local grocery store to promote healthier purchasing, with a goal of removing visceral factors that can lead to impulse purchases in stores. The second intervention, Defaults, will augment the Online intervention, showing participants a default shopping cart when they log into their accounts. They will be told that their cart has been filled with items that conform to a diabetic diet and can be used to make the recipes from the provided recipe cards, and that they may modify their carts as they like. In the control group, participants will shop in‐person as usual. At baseline, all participants will complete a survey online or via phone and then will grocery shop in‐person as usual. Participants will then be randomized and receive further instructions. For the next 3 weeks, they will receive recipe cards and shop in accordance with their assigned study group. The following week (post), they will grocery shop using the mode of their choice (in‐person or online) and complete a survey again. Household receipt data will be collected throughout the study. The baseline period will also serve as a run‐in period, and participants whose diabetes/prediabetes status is not confirmed by a physician or who do not comply with study guidelines for baseline procedures will not be randomized for further participation. Primary analyses will examine intervention effects on grocery purchases, with additional analyses examining spending and dietary intake. All participant interactions will occur online or via phone, with cards for participant payment sent via postal mail. The specific aims of this study are: (1) to test effects of Online and Defaults interventions on diabetic adults' grocery purchases and (2) to explore effects of the Online and Defaults interventions on participants' spending during grocery shopping. It is hypothesized that (1a) purchases made by adults in the Defaults group will be lower in calories, carbohydrates, and sugar and higher in nutritional quality (DASH diet score) at post‐test versus other study groups, (1b) adults in the Defaults group will show the greatest increases in nutritional quality versus other study groups, (1c) the Online group will have intermediary results between Defaults and Controls, and (2) there will be no difference in total dollars depicted on receipts across study groups during the intervention period (i.e. the costs of online shopping will be offset by effects of the Online and Default interventions).