Effects of a grocery shopping intervention designed to improve diet adherence in diabetes: a randomized trial

Objective: The goal of this study was to examine the potential of an optimal-defaults intervention to promote grocery purchases corresponding to a diet for diabetes. Methods: In total, 65 adults diagnosed with or at increased risk for type 2 diabetes who grocery shopped at one of two study stores were randomized to one of three groups: Defaults, Online, or Control. All groups received diabetes-friendly recipes. In addition, the Online group was asked to grocery shop online during a 3-week intervention, and the Defaults group was asked to shop online, with their online grocery carts prefilled with food items needed to prepare provided recipes. Participants provided weekly grocery receipt data at baseline, at each week of the 3-week intervention, and at post-intervention. Results: Overall, the Defaults group had grocery purchases of a significantly greater nutritional quality versus other groups (F = 16.3, p < 0.001). Between-group comparisons of least-squares means showed consistent effects of the Defaults intervention while intervention components were in place, with a similar pattern for energy and carbohydrate content of grocery purchases. Conclusions: These results build upon emerging evidence that optimal defaults can promote healthier grocery purchases. Continued examination of this approach could promote healthy food acquisition in accordance with individual dietary preferences and needs.