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

Not Applicable

Completed

• Conditions: Eating Behaviour
• Interventions: Behavioral: Food-based Control Condition; Behavioral: Liking Social Norm; Behavioral: Descriptive Social Norm; Behavioral: Neutral Control Condition; Behavioral: Health Condition

• Registration Number: NCT02618174
• Lead Sponsor: University of Birmingham

Brief Summary

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

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.

Study Timeline

• Study Start: 2013-10
• Primary Completion: 2014-07
• Study Completion: 2014-07
• Status Verified: 2015-11
• Study First Submitted: 2015-11-24
• Study First Submitted QC: 2015-11-27
• Last Update Submitted: 2015-11-27
• Study First Posted: 2015-12-01
• Last Update Posted: 2015-12-01

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 400

Inclusion Criteria

• Healthy volunteers
• Sufficiently fluent in English

Exclusion Criteria

• Smokers
• Diabetes
• Food allergies
• Past / present depression or anxiety
• Past / present eating disorder.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Food-based Control Condition	Food-based Control Condition	Message about variety of vegetables in the world
Liking Social Norm	Liking Social Norm	Message suggesting most people like eating vegetables
Descriptive Social Norm	Descriptive Social Norm	Message suggesting most people eat plenty of vegetables
Neutral Control Condition	Neutral Control Condition	Message about age of University of Birmingham
Health Condition	Health Condition	Message about the health benefits of eating vegetables

Primary Outcome Measures

Name	Time	Method
Grams of vegetables consumed	8 months

Trial Locations

Locations (1)

University of Birmingham; 🇬🇧 Birmingham, West Midlands, United Kingdom