Delay discounting and household food purchasing decisions: The SHoPPER study

Abstract

Objective: Delay discounting is a neurocognitive trait that has been linked to poor nutritional health and obesity, but its role in specific dietary choices is unclear. This study tested whether individual differences in delay discounting are related to the healthfulness of household food purchases and reliance on nonstore food sources such as restaurants.

Method: The food purchases of 202 primary household food shoppers were objectively documented for 14 days through a food receipt collection and analysis protocol. The nutrient content of household food purchases was derived for each participant, and the overall diet quality (Healthy Eating Index-2015) and energy density (kcal/g) of foods and beverages were calculated. The proportion of energy from nonstore food sources was also derived. Delay discounting was assessed with a choice task featuring hypothetical monetary rewards.

Results: Data were available for 12,624 foods and beverages purchased across 2,340 shopping episodes. Approximately 13% of energy was purchased from restaurants and other nonstore food sources. Steeper discounting rates were associated with lower overall Healthy Eating Index-2015 scores and a higher energy density (kcal/g) of purchased foods. Associations were attenuated but remained statistically significant when accounting for body mass index and sociodemographic variables. Discounting rates were unrelated to reliance on nonstore food sources or the energy density of purchased beverages.

Conclusions: Delay discounting is related to the healthfulness of food purchases among primary household shoppers. As food purchasing is a key antecedent of dietary intake, delay discounting may be a viable target in dietary and weight management interventions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Trial registration: ClinicalTrials.gov NCT02073643.

Figure 1.

Predicted association between delay discounting (area under the curve of indifference points) and the diet quality of household food purchases based on the Healthy Eating Index-2015, adjusted for demographic factors and body mass index. Higher values for delay discounting reflect a lower discounting rate, or less impulsive responding on the task.

Figure 2.

Predicted association between delay discounting (area under the curve of indifference points) and the energy density (kcal/g) of purchased foods, adjusted for demographic factors and BMI. Higher values for delay discounting reflect a lower discounting rate, or less impulsive responding on the task.