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

University of Birmingham

Status: Completed

Conditions: Eating Behaviour

Treatments: Behavioral: Food-based Control Condition; Behavioral: Neutral Control Condition; Behavioral: Descriptive Social Norm; Behavioral: Health Condition; Behavioral: Liking Social Norm

Study type: Interventional

Funder types: Other

Identifiers

NCT02618174

UBirmingham-SNS1

Details and patient eligibility

About

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).

Full 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.

Enrollment: 400 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Healthy volunteers
• Sufficiently fluent in English

Exclusion criteria

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

Trial design

400 participants in 5 patient groups, including a placebo group

Neutral Control Condition

Placebo Comparator group

Description:

Message about age of University of Birmingham

Treatment:

Behavioral: Neutral Control Condition

Food-based Control Condition

Placebo Comparator group

Description:

Message about variety of vegetables in the world

Treatment:

Behavioral: Food-based Control Condition

Health Condition

Active Comparator group

Description:

Message about the health benefits of eating vegetables

Treatment:

Behavioral: Health Condition

Descriptive Social Norm

Active Comparator group

Description:

Message suggesting most people eat plenty of vegetables

Treatment:

Behavioral: Descriptive Social Norm

Liking Social Norm

Experimental group

Description:

Message suggesting most people like eating vegetables

Treatment:

Behavioral: Liking Social Norm