Delays to Influence Snack Choice (DISC)

Time Over Money? A Novel System to Influence Snack Machine Choices

The pervasiveness of high-calorie, nutrient-poor snacks in the environment is believed to have contributed to the epidemic levels of obesity and cardiometabolic disease in the U.S. This project tests whether a novel snack vending machine system that uses brief time delays to reduce the immediacy of reward from unhealthy snacks will improve the healthfulness of snack choices. If successful, this project will identify a new environmental intervention that could contribute substantially to obesity and cardiometabolic disease prevention efforts in schools, worksites, and other settings.

Study Overview

• Status: Completed
• Conditions: Food Choice
• Intervention / Treatment: Other: 25%/$0.25 discount on healthy snacks; Other: Time delays on delivery of less healthy snacks; Other: 25%/$0.25 tax on less healthy snacks

Detailed Description

Environmental interventions that address the high availability of unhealthy snacks in the environment are needed to prevent a large projected increase in the incidence of obesity and cardiometabolic disease in the U.S. Prior studies from the investigators group and others suggests that the human preference for immediate gratification from food drives dietary overconsumption, but this knowledge has not yet translated to more effective dietary intervention strategies. This project tests whether a novel snack vending machine system that uses brief time delays to reduce the immediacy of reward from unhealthy snacks will improve the healthfulness of snack choices. This study uses an experimental design to compare brief time delays, two forms of 25% differential pricing, and time delays combined with both forms of 25% differential pricing on their ability to increase purchasing of healthy snacks. Test machines will be placed in existing, high-volume vending locations, and each of these five experimental conditions will run for roughly four weeks. Additionally, baseline purchasing under no intervention will be monitored for four weeks before and four weeks after the five experimental conditions. Specific Aim 2 compares the effects of these five interventions against baseline on the proportion of total vending sales from healthy snacks. Specific Aim 3 tests whether time delays or differential pricing harm overall vending machine sales in the test machines. This study not only tests a compelling theory about the effects of time delays and immediate reward on food choice, but evaluates the efficacy and feasibility of a novel intervention to improve the healthfulness of snack choices in worksites, schools, and other settings.

• Study Type: Observational
• Enrollment (Actual): 32662

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60612
      • Rush University Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

This is an environmental intervention. No subjects will be recruited or enrolled.

Description

Inclusion Criteria:

• Not applicable

Exclusion Criteria:

• Not applicable

Study Plan

How is the study designed?

Number of groups / cohorts

7

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
A; Snacks sold under equal pricing, no delays
B; Healthier snacks sold at 25% or $0.25 discount, no delays	Other: 25%/$0.25 discount on healthy snacks
C; Less healthy snacks sold at equal pricing with delays	Other: Time delays on delivery of less healthy snacks
D; Healthy snacks sold at 25% or $0.25 discount, plus delays on less healthy snacks	Other: 25%/$0.25 discount on healthy snacks; Other: Time delays on delivery of less healthy snacks
E; Less healthy snacks sold at 25% or $0.25 higher price, no delays	Other: 25%/$0.25 tax on less healthy snacks
F; Less healthy snacks sold at 25% or $0.25 higher price, plus delays	Other: Time delays on delivery of less healthy snacks; Other: 25%/$0.25 tax on less healthy snacks
G; Snacks sold under equal pricing, no delays

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Healthy Snacks Purchased	For each experimental condition, we will calculate the proportion of healthy vs unhealthy snacks sold over 4 weeks.	28 weeks per vending location

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Daily Vending Revenue in US$/Day	Total vending machine revenue under each condition	Number of days per condition were as follows - Baseline: 119 days, Discount only: 59 days, Delay only: 68 days, Delay + Discount: 49 days, Tax only: 73 days, Delay + Tax: 60 days

Collaborators and Investigators

• Sponsor: Rush University Medical Center
• Investigators: Principal Investigator: Bradley M Appelhans, PhD, Associate Professor

Publications and helpful links

General Publications

• Appelhans BM, French SA, Olinger T, Bogucki M, Janssen I, Avery-Mamer EF, Powell LM. Leveraging delay discounting for health: Can time delays influence food choice? Appetite. 2018 Jul 1;126:16-25. doi: 10.1016/j.appet.2018.03.010. Epub 2018 Mar 15.

Study record dates

Study Major Dates

• Study Start: June 1, 2015
• Primary Completion (Actual): August 1, 2016
• Study Completion (Actual): August 1, 2016

Study Registration Dates

• First Submitted: February 2, 2015
• First Submitted That Met QC Criteria: February 4, 2015
• First Posted (Estimate): February 10, 2015

Study Record Updates

• Last Update Posted (Actual): February 23, 2018
• Last Update Submitted That Met QC Criteria: January 25, 2018
• Last Verified: January 1, 2018

More Information

Terms related to this study

• Other Study ID Numbers: 13012802