Promoting Healthier Grocery Purchases in Participants With Type 2 Diabetes

Grocery store purchases had a higher nutritional value when patients with type 2 diabetes (T2D) were given default grocery store orders based on a predetermined diet, a study published in Obesity shows.

Dietary approaches have been recommended for avoiding and managing obesity and T2D. Optimal defaults have been proven as effective in making healthy choices easier in food choice scenarios, including at restaurants, for people who struggle with maintaining a diet. This current study aimed to discover the potential of an optimal defaults intervention in promoting healthy food selection while grocery shopping in adults with T2D.

All participants were recruited from summer 2019 to fall 2020. They needed to be 18 years and older; have prediabetes, T2D, or be at an increased risk of developing T2D; reported doing at least 75% of the grocery shopping in their household; reported shopping in person at one of the 2 study grocery stores at least weekly; were fluent in English; were not a recipient of food assistance; did not have dietary restrictions; and did not recently participate in studies of shopping or eating behavior.

Participants were split into 3 groups: control, online, and default. The control group did their grocery shopping in person during the 3-week intervention. The online group did all of their grocery shopping online without guidance. The default group shopped online and had a prefilled online shopping cart with all of the ingredients they needed to prepare recipes that were diabetes friendly. These recipes came from the Dietary Approaches to Stop Hypertension (DASH) diet.

Participants used their normal method of grocery shopping in the postintervention week with the removal of recipes and default carts. These participants also completed an exit survey. All participants’ grocery purchases were given a calculated nutritional quality score that corresponded to the DASH diet.

There were 65 participants split into 3 groups included in this study. There were no significant differences in the groups in baseline variables or demographics. Participants with higher body mass index (BMI) had less sugar in their grocery purchases at baseline. A total of 95.5% of the defaults group accepted at least some of the items in their prefilled cart, which dipped to 85.7% by week 4.

Higher nutritional value in groceries purchased was found in the defaults group (F = 16.3; P < .001 for the a priori contrast that compared the defaults group with the other groups). The defaults intervention was found to mitigate the decline of nutritional quality over time and had consistent and significant effects while in place.

Some evidence of improvements in the defaults group was noted in the group differences in least-squares means. The difference between the default group and the other groups was a d of 0.29 and 0.24 for energy and carbohydrate content of purchases, respectively, which are small effects. Small effects of the default intervention also were found in energy and carbohydrate content in the postintervention week (d = 0.28 for both). These effects were larger during intervention weeks (d = 0.46 for energy; d = 0.40 for carbohydrates; d = 0.34 for sugar, all in week 4).

The nature of the results was similar after repeating the analyses in relation to total items purchased, but energy (F = 7.13; P < .01) and carbohydrate (F = 4.41; P < .05) purchases in the default group were significantly lower compared with the other 2 groups.

There were some limitations to this study. The population was homogeneous and did not include low-income households reliant on food assistance. The study also focused on 2 local chain grocery stores. and receipts were only collected if they came from the 2 grocery stores, which is less comprehensive. The study was also paused from March to May of 2020, when grocery shopping was most affected.

The researchers concluded that optimal defaults are a promising way to promote healthier purchases at the grocery store for participants who have or who may be at risk for T2D.

Reference

Anzman-Frasca S, McGovern L, Ferrante MJ, et al. Effects of a grocery shopping intervention designed to improve diet adherence in diabetes: a randomized trial. Obesity. Published online November 29, 2022. doi:10.1002/oby.23588