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Completed

NCT Number: NCT02618174

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

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).

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Key information

Conditions

Eating Behaviour Behavior Behavior, Animal Feeding Behavior

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Birmingham

Birmingham, West Midlands, B15 2TT, United Kingdom

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy volunteers
  • Sufficiently fluent in English

Exclusion criteria

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

Treatment and study plan

Neutral Control Condition

Behavioral

Message about age of University of Birmingham

Food-based Control Condition

Behavioral

Message about variety of vegetables in the world

Health Condition

Behavioral

Message about the health benefits of eating vegetables

Descriptive Social Norm

Behavioral

Message suggesting most people eat plenty of vegetables

Liking Social Norm

Behavioral

Message suggesting most people like eating vegetables

Primary outcomes

  1. Grams of vegetables consumed

    Time frame: 8 months

Sponsors and collaborators

Lead sponsor

University of Birmingham

Other

Collaborators

  • Economic and Social Research Council, United Kingdom

Registry information

Important dates

Study start
2013
Primary completion
2014
Study completion
2014
First posted
Dec 1, 2015
Registry last updated
Dec 1, 2015

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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