Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Repeated exposure to a taste, along with sticker rewards for tasting, can increase children's acceptance of disliked foods but previous studies have been intensive and would be difficult and expensive to make widely available. This study aims to test if mailed materials giving parents instructions on taste exposure and rewards can effectively increase acceptance of vegetables in preschool-aged children.

Who can participate?
The study will recruit families with young twins from the Gemini cohort (

What does the study involve?
Families who elect to participate will be randomly allocated to an intervention group or a no-treatment control group. All families will be asked to select a vegetable both their twins dislike. Parents will be instructed to measure their children's intake (number of pieces) and liking of the target vegetable at test sessions before and after the intervention. The families in the intervention group will also receive an information pack and a link to an online video. Intervention group parents will offer each of their twins 14 daily tastes of a disliked vegetable and provide a sticker reward if they taste it. The control group families will receive the intervention materials only after completing the study.

What are the possible benefits and risks of participating?
The study may increase children's acceptance of previously rejected vegetables. No risks are expected.

Where is the study run from?
The study has been set up by the Health Behaviour Research Centre at University College London (UK).

When is the study starting and how long is it expected to run for?
Recruitment will start in early 2011 and the study will run for about 1 year.

Who is funding the study?
The recruitment of the Gemini cohort was funded by a grant from Cancer Research UK, and the design and production of the packs used in this study was funded by Weight Concern.

Who is the main contact?
Professor Jane Wardle

Trial website

Contact information



Primary contact

Dr Lucy Cooke


Contact details

Health Behaviour Research Centre
1-19 Torrington Place
United Kingdom
+44 (0)20 7679 1615

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

The influence of rewards on children's vegetable acceptance: a home-based randomised controlled trial


Study hypothesis

Both tangible and social rewards (when paired with repeated exposure) would increase the acceptance of a moderately disliked vegetable when compared with a no-treatment control condition

This is second of two studies on incentives in child feeding, the first of which was registered under ISRCTN42922680.

Ethics approval

UCL Research Ethics Committee, 27/11/2009, ref: 2174/001

Study design

Home-based randomised controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type

Quality of life

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Children's nutrition


All children will participate in pre-intervention, post-intervention and 1- and 3-month follow-up assessments

Children will be randomly assigned to one of three conditions:
1. Tangible reward: daily offer of target vegetable for 12 days with a sticker reward given for tasting
2. Social reward: daily offer of target vegetable for 12 days with specific praise given for tasting
3. Control: no tasting between assessment sessions

Intervention type



Not Applicable

Drug names

Primary outcome measure

1. Children's liking of their target vegetable (3-point faces scale: 1 = 'Yucky', 2= 'OK', 3= 'Yummy')
2. Consumption of the target vegetable in grams
Both measures taken pre-intervention, post-intervention and at 1- and 3-month follow-up

Secondary outcome measures

1. Parental feeding practices
2. Child's food fussiness
3. Liking and frequency of consumption of a range of fruit and vegetables

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Children aged 3-4 years and their care giver
2. Care giver fluent in written and spoken English

Participant type


Age group




Target number of participants


Participant exclusion criteria

Signifcant learning difficulties or physical problems affecting feeding and eating

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Health Behaviour Research Centre
United Kingdom

Sponsor information


University College London (UK)

Sponsor details

Department of Epidemiology and Public Health
Health Behaviour Research Centre
Gower Street
United Kingdom
+44 (0)20 7679 2000

Sponsor type




Funder type

Research council

Funder name

Medical Research Council (MRC) - National Prevention Research Initiative (NPRI) (UK) (ref: G0701864)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2014 results in:

Publication citations

  1. Results

    Fildes A, van Jaarsveld CH, Wardle J, Cooke L, Parent-administered exposure to increase children's vegetable acceptance: a randomized controlled trial., J Acad Nutr Diet, 2014, 114, 6, 881-888, doi: 10.1016/j.jand.2013.07.040.

Additional files

Editorial Notes