Delays to Influence Snack Choice

Completed

Conditions: Food Choice

Interventions: Other: Time delays on delivery of less healthy snacks
Other: 25%/$0.25 tax on less healthy snacks
Other: 25%/$0.25 discount on healthy snacks

Registration Number: NCT02359916

Lead Sponsor: Rush University Medical Center

Brief Summary: 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.

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.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 32662

Inclusion Criteria

Not applicable

Exclusion Criteria

Not applicable

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
F	25%/$0.25 tax on less healthy snacks	Less healthy snacks sold at 25% or $0.25 higher price, plus delays
D	25%/$0.25 discount on healthy snacks	Healthy snacks sold at 25% or $0.25 discount, plus delays on less healthy snacks
E	25%/$0.25 tax on less healthy snacks	Less healthy snacks sold at 25% or $0.25 higher price, no delays
F	Time delays on delivery of less healthy snacks	Less healthy snacks sold at 25% or $0.25 higher price, plus delays
B	25%/$0.25 discount on healthy snacks	Healthier snacks sold at 25% or $0.25 discount, no delays
C	Time delays on delivery of less healthy snacks	Less healthy snacks sold at equal pricing with delays
D	Time delays on delivery of less healthy snacks	Healthy snacks sold at 25% or $0.25 discount, plus delays on less healthy snacks

Primary Outcome Measures

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

Secondary Outcome Measures

Name	Time	Method
Total Daily Vending Revenue in US$/Day	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	Total vending machine revenue under each condition