Delays to Influence Snack Choice

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Food Choice

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


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Not applicable Exclusion Criteria: Not applicable
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

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

What is the study measuring?
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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 |