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
Many studies have shown that people from poorer backgrounds tend to eat more unhealthy foods that those who are more privileged. Some think that studies which aim to educate people and change their behaviour may not work as well for people from disadvantaged communities as their ability for self-control (executive function) may be lower. This is a particular concern as it may widen the gap between the dietary habits of these two groups, and so a different type of study may be needed to find the best way to help those from disadvantaged backgrounds to change their diets. Making changes to the environment, such as placing food further away, is thought to change people’s behaviour unconsciously. People generally eat more of a food when it is placed within reach, regardless of the type of food or that person’s usual habits. Many studies testing this principle tend to test only university staff and students, which is not an accurate representation of the general population. The aim of this study is to find out whether the distance of food changes the amount of food a person eats and to find out whether this is related to a person’s executive function.

Who can participate?
Healthy adults who live in Cambridge and surrounding areas.

What does the study involve?
Participants are randomly allocated into two groups. Each group is provided with snack foods in a bowl during a 10 minute “relaxation break” which is placed either 20cm or 70cm away from them. After the 10 minute break, the weight of the snack bowls is measured to find out how much the participants from each group have eaten and the number of participants who ate the snacks from each group is recorded. Participants are also asked to complete a questionnaire designed to test their executive function at the start of the study, and a questionnaire to determine their response to the snacks after the study.

What are the possible benefits and risks of participating?
There are no direct benefits for participants; however the study will help to provide information about ways of influencing eating behaviour that can be applied to further research. There are no risks of participating in the study.

Where is the study run from?
University of Cambridge Institute of Public Health (UK)

When is the study starting and how long is it expected to run for?
November 2014 to March 2016

Who is funding the study?
1. Medical Research Council (UK)
2. Department of Health Policy Research Programme (UK)

Who is the main contact?
Professor Theresa Marteau

Trial website

Contact information



Primary contact

Prof Theresa Marteau


Contact details

University of Cambridge
Institute of Public Health
Forvie Site
United Kingdom

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Impact of altering proximity on snack food intake in individuals with high and low executive function


Study hypothesis

1. Consumption of a snack food is less likely when it is placed further from participants
2. The proximity effect is not moderated by executive function

Ethics approval

Cambridge Psychology Research Ethics Committee, 16/03/2015, ref: Pre.2015.008

Study design

Single-centre randomised parallel trial

Primary study design


Secondary study design

Randomised parallel trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


Unhealthy diet


Participants are told they will be taking part in a relaxation study so that the snack food can be placed without making participants aware that the study is about eating behaviour (awareness of the role of food may affect their eating behaviour). Participants are fully debriefed at the end of the session. Participants are randomly allocated into two groups, who are provided with snack foods which are place different distances away:
Group 1: Snack food is placed at 20cm from the participant
Group 2: Snack food is placed at 70cm from the participant
Before the snack food is brought into the room, participants complete tasks to measure executive function. After the snacks are removed from the room, participants complete questions relating to the snacks used in the study, such as ratings of effort to take the snacks and how tempting the snacks appeared.

Intervention type



Drug names

Primary outcome measure

The proportion of participants who consume any snack food, measured as any difference in bowl weight from before to after the participant is exposed to the snacks.

Secondary outcome measures

1. The mean amount of snack food consumed, measured as the difference in bowl weight from before to after the participant is exposed to the snacks
2. Executive function, measured using the Stroop task (Stroop, 1935) before exposure to the snack food
3. Ratings of perceived effort to obtain the snacks and salience of the snacks, collected using a questionnaire following exposure to the snack food

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Adults aged over 18 years
2. In the Cambridge area and surrounding areas (Stevenage, Peterborough)

Participant type

Healthy volunteer

Age group




Target number of participants


Participant exclusion criteria

Any food allergies or intolerances

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

The Behaviour and Health Research Unit
University of Cambridge Institute of Public Health Forvie Site Robinson Way
United Kingdom

Sponsor information


University of Cambridge (UK)

Sponsor details

Trinity Lane
United Kingdom

Sponsor type




Funder type

Research council

Funder name

Medical Research Council

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government


United Kingdom

Funder name

Department of Health Policy Research Programme

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

We intend to submit the main results of this study for publication in a high-impact factor journal.

IPD sharing statement:
The current data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

See additional file ISRCTN46995850_BasicResults_09Mar17

Publication list

2016 protocol in:
2017 results in:

Publication citations

Additional files

Editorial Notes

01/12/2017: Publication reference added. 08/06/2017: The basic results of this trial have been updated to include the completed analysis of the secondary outcome measures. 15/03/2017: The basic results of this trial have been uploaded as an additional file. Overall trial start date was changed from 11/11/2015 to 11/11/2014. Added individual participant data (IPD) sharing plan. 14/06/2016: Publication reference added.