CTSI Pilot: Improving Adherence to Diabetic Diet

425 million adults live with diabetes worldwide, and the prevalence of Type 2 diabetes is rising. Dietary approaches are recommended for weight control and diabetes management, but modern environments, characterized by plentiful, unhealthy foods, pose challenges to selecting a healthy diet. Behavioral economics offers a framework for modifying the food environment to encourage individuals with diabetes to select low-calorie and low-sugar foods. The goal of this study is to test novel approaches informed by behavioral economics to promote healthier grocery shopping among diabetic patients. Adults who have Type 2 diabetes or who are at risk for developing Type 2 diabetes will be recruited. Participants will be randomly assigned to 1 of 2 interventions or a control group in which they will shop in-person as usual. The Online intervention will utilize online grocery shopping to promote healthier purchasing. The Defaults intervention will augment this intervention, showing participants a default shopping cart pre-filled with items that correspond to the DASH diet and diabetic diet goals, which they may modify as they like. Receipt data will be collected to quantify the alignment of purchases with diabetic diet goals before, during, and after interventions. Purchases lower in calories, carbohydrates, and sugar and higher in nutritional quality (DASH diet score) are expected in the Defaults group; the Online group is expected to have intermediary results between Defaults and Controls. The investigators will also explore effects of the interventions on spending and dietary intake. This study is intended to demonstrate the efficacy of strategies that leverage behavioral economics principles to make the purchasing of healthier foods easier. The strategies have translational significance as they could be incorporated into clinical treatment, with the potential to improve dietary intake, glucose regulation, weight, and medication needs among diabetic patients.

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).

Eligibility Criteria:
Inclusion Criteria:

* Must be at least 18 years old
* Must have been diagnosed diabetes or demonstrate diabetes risk as defined by the American Diabetes Association
* Must shop in-person at select local grocery stores at least weekly, and at least 75% of the grocery shopping for the household must be done at these stores
* Must do at least 75% of the grocery shopping for the household
* Must speak English

Exclusion Criteria:

* Is under 18 years of age
* Does not meet diabetes/risk for diabetes criteria
* Does not shop in-person at select local grocery stores at least weekly
* Does not live in a household in which 75% of groceries come from select local grocery stores
* Does not do at least 75% of the grocery shopping for the household
* Does not speak English
* Receives SNAP or WIC benefits (an exclusion criterion for this study due to incompatibility of EBT cards with the selected online grocery shopping platform at this time)
* Has dietary restrictions or preferences that would not allow them to reasonably partake in the study (i.e. they would not be willing or able to buy/eat many of the staple foods included in default carts/recipe cards)