Enhanced Broccoli Consumption After a Liking Norm and Vegetable Variety Message: Effects After a 24 Hour Delay.

Study Overview
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Brief Summary
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Encouraging individuals to eat vegetables is difficult. However, recent evidence suggests that using social-based information might help. For instance, it has been shown that if people think that others are eating lots of fruit and vegetables, that they will consume more of these foods to match the 'norm'. The purpose of this study was to determine whether a liking social norm (information about how much others like vegetables) would be effective at encouraging people to eat more vegetables and to examine whether these effects are sustained beyond initial exposure (i.e. whether the effect of the norm persists on food selection 24 hours alter).

Detailed Description
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Using a 2 x 5 x 2 experimental design we investigated the effects of exposure to various messages on later food intake and whether any effects were sustained 24 hours after exposure in both low and high consumers of vegetables. There were three factors of delay (immediate food selection versus food selection 24 hours after exposure), message type (liking norm, descriptive norm, health message, food-based control, and neutral control message) and habitual consumption (low versus high). The buffet consisted of three raw vegetables, three energy-dense foods and two dips. In this study the investigators hypothesised that a liking norm would increase the consumption of vegetables (compared to a neutral control condition) and that the effect would persist on vegetable consumption 24 hours after intital exposure to the liking norm.

Official Title
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Enhanced Broccoli Consumption After a Liking Norm and Vegetable Variety Message: Effects After a 24 Hour Delay.

Conditions
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Eating Behaviour

Intervention / Treatment
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* Behavioral: Neutral Control Condition
* Behavioral: Food-based Control Condition
* Behavioral: Health Condition
* Behavioral: Descriptive Social Norm
* Behavioral: Liking Social Norm


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy volunteers Sufficiently fluent in English Exclusion Criteria: Smokers Diabetes Food allergies Past / present depression or anxiety Past / present eating disorder.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

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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Design Details

Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Neutral Control Condition<br>Message about age of University of Birmingham | Behavioral: Neutral Control Condition<br>* Message about age of University of Birmingham<br>|
| Placebo Comparator: Food-based Control Condition<br>Message about variety of vegetables in the world | Behavioral: Food-based Control Condition<br>* Message about variety of vegetables in the world<br>|
| Active Comparator: Health Condition<br>Message about the health benefits of eating vegetables | Behavioral: Health Condition<br>* Message about the health benefits of eating vegetables<br>|
| Active Comparator: Descriptive Social Norm<br>Message suggesting most people eat plenty of vegetables | Behavioral: Descriptive Social Norm<br>* Message suggesting most people eat plenty of vegetables<br>|
| Experimental: Liking Social Norm<br>Message suggesting most people like eating vegetables | Behavioral: Liking Social Norm<br>* Message suggesting most people like eating vegetables<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Grams of vegetables consumed |  | 8 months |