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

• ClinicalTrials.gov Identifier: NCT02618174
• Recruitment Status: Completed
• First Posted: December 1, 2015
• Last Update Posted: December 1, 2015
• Sponsor: University of Birmingham
• Collaborator: Economic and Social Research Council, United Kingdom
• Information provided by (Responsible Party): University of Birmingham

Study Description

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).

Condition or disease	Intervention/treatment	Phase
Eating Behaviour	Behavioral: Neutral Control Condition; Behavioral: Food-based Control Condition; Behavioral: Health Condition; Behavioral: Descriptive Social Norm; Behavioral: Liking Social Norm	Not Applicable

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 Design

• Study Type: Interventional (Clinical Trial)
• Actual Enrollment: 400 participants
• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Masking: Single (Participant)
• Official Title: Enhanced Broccoli Consumption After a Liking Norm and Vegetable Variety Message: Effects After a 24 Hour Delay.
• Study Start Date: October 2013
• Actual Primary Completion Date: July 2014
• Actual Study Completion Date: July 2014

Arms and Interventions

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

Outcome Measures

Primary Outcome Measures :

1. Grams of vegetables consumed [ Time Frame: 8 months ]

Eligibility Criteria

• Ages Eligible for Study: 18 Years to 65 Years (Adult, Older Adult)
• Sexes Eligible for Study: All
• Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:

• Healthy volunteers
• Sufficiently fluent in English

Exclusion Criteria:

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

Contacts and Locations

Locations

United Kingdom

University of Birmingham

Birmingham, West Midlands, United Kingdom, B15 2TT

Sponsors and Collaborators

University of Birmingham

Economic and Social Research Council, United Kingdom

Investigators

• Principal Investigator: Jason M Thomas, PhD; University of Birmingham

More Information

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Thomas JM, Liu J, Robinson EL, Aveyard P, Herman CP, Higgs S. The Effects of Liking Norms and Descriptive Norms on Vegetable Consumption: A Randomized Experiment. Front Psychol. 2016 Mar 30;7:442. doi: 10.3389/fpsyg.2016.00442. eCollection 2016.

• Responsible Party: University of Birmingham
• ClinicalTrials.gov Identifier: NCT02618174
• Other Study ID Numbers: UBirmingham-SNS1
• First Posted: December 1, 2015
• Last Update Posted: December 1, 2015
• Last Verified: November 2015