To what extent can the effects of increasing healthier food availability on food selection be explained by individual food preferences? A follow-up study
| ISRCTN | ISRCTN61010183 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN61010183 |
| Secondary identifying numbers | Pre.2020.030 |
- Submission date
- 07/04/2020
- Registration date
- 20/04/2020
- Last edited
- 27/10/2022
- Recruitment status
- No longer recruiting
- Overall study status
- Completed
- Condition category
- Nutritional, Metabolic, Endocrine
Plain English Summary
Background and study aims
Increasing the availability of healthier or more plant-based foods increases their selection. One possible mechanism that might underlie these effects is individuals’ prior preferences, whereby selections reflect individuals’ most-preferred option from the available range. The first exploration – to the researchers' knowledge – of the role of prior preferences as a possible mechanism underlying the effects of manipulating the relative availability of healthier and less healthy options suggested that a large majority of selections reflect the most-preferred option. However, only small differences were observed in preferences by option healthiness in this initial study. The role of preferences will be further explored in this study.
Who can participate?
Adults over the age of 18 with no dietary restrictions
What does the study involve?
The study will be conducted online. First, each study will establish each participant’s baseline relative preferences between all the food options used in the study. To do so, participants are asked to choose which option they would prefer to eat right now from pairs of food options. These pairs represent every possible pairing of food options used in the study. This allows each food option to subsequently be ranked in terms of each participant’s preferences. Participants are then shown two images, with four options displayed in each, and asked to again select the option they would most like to eat right now. These images will show either predominantly-less-healthy main meals, or predominantly-healthier main meals. The predominantly-less-healthy set will contain three options defined as less-healthy and one healthier option; vice versa for the predominantly-healthier set. Participants will see each of these two images in a random order. The data from the study will be used to assess the extent to which increasing the availability of healthier options alters the healthiness of participants’ most-preferred option, and the extent to which the option selected by participants corresponds to their most-preferred option.
What are the possible benefits and risks of participating?
Participants will be paid the equivalent of UK minimum wage for participating in these studies. There are no known risks of participating in either study.
Where is the study run from?
Behaviour and Health Research Unit, University of Cambridge (UK)
When is the study starting and how long is it expected to run for?
February 2020 to July 2020
Who is funding the study?
Wellcome Trust (UK)
Who is the main contact?
Dr Rachel Pechey
rachel.pechey@phc.ox.ac.uk
(updated 07/01/2021, previously: rachel.pechey@medschl.cam.ac.uk)
Contact information
Scientific
Nuffield Department of Primary Care Health Sciences
University of Oxford
Radcliffe Primary Care Building
Radcliffe Observatory Quarter
Woodstock Rd
Oxford
OX2 6GG
United Kingdom
 ORCID ID |
0000-0002-6558-388X |
|---|---|
| rachel.pechey@phc.ox.ac.uk |
Study information
| Study design | Single-centre 2x2 within-subjects design |
|---|---|
| Primary study design | Interventional |
| Secondary study design | Randomised cross over trial |
| Study setting(s) | Internet/virtual |
| Study type | Other |
| Participant information sheet | Not available in web format, please use the contact details to request a patient information sheet |
| Scientific title | Increasing the relative availability of healthier vs less healthy food: can impact be explained in terms of prior preferences? An extension study |
| Study hypothesis | 1. Reducing less healthy options and increasing healthier options increases the likelihood of participants’ most-preferred option being a healthier option a. Reducing less healthy options and increasing healthier options increases the likelihood of participants’ most-preferred option being a healthier option to a greater extent for those with higher education (vs lower education) 2. Participants’ most-preferred option within the offered range of products will often, but not always, correspond to the option that participants select I. Participants’ most-preferred option within the offered range of products is more likely to correspond to the option that participants select when the option selected is less-healthy (vs healthier) |
| Ethics approval(s) | Approved 30/03/2020, Cambridge Psychology Research Ethics Committee (School of the Biological Sciences, 17 Mill Lane, Cambridge, CB2 1RX, UK; +44 (0)1223 766894; Cheryl.torbett@admin.cam.ac.uk), ref: Pre.2020.030 |
| Condition | Unhealthy diet |
| Intervention | When accessing the online study, participants are randomly allocated to the order in which they complete two conditions, which vary in terms of the mix of healthier and less healthy foods offered and the type of food offered: Condition 1: Selection contains 1 healthier and 3 less healthy main meals. Condition 2: Selection contains 3 healthier and 1 less healthy main meals. Participants will be shown an image of a set of options representing each condition, in a random order. For each image, participants will be asked to select which option they would prefer to eat right now. The food options assigned to each condition will be randomly selected from a pool of available healthier vs. less-healthy options. The position of selected food options in each image will also be randomised. Randomisation will be performed by the Qualtrics survey platform. |
| Intervention type | Behavioural |
| Primary outcome measure | Measured at a single timepoint (on completion of the online survey): 1. Healthiness (healthier vs. less-healthy) of participants’ most-preferred option (measured via rankings determined from selections between each possible item pair in the first part of the study) in each of the two conditions in the online selection task 2. Correspondence between participants’ selections in each of the two conditions in the online selection task and their most-preferred options (measured via rankings determined from selections between each possible item pair in the first part of the study) |
| Secondary outcome measures | Measured at a single timepoint (on completion of the online survey): Selection of a healthier (vs. less healthy) food option in the online selection task for each of the two conditions |
| Overall study start date | 01/02/2020 |
| Overall study end date | 31/07/2020 |
Eligibility
| Participant type(s) | Healthy volunteer |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | Both |
| Target number of participants | 1080 |
| Total final enrolment | 1078 |
| Participant inclusion criteria | 1. Adults aged over 18 years 2. Participants currently residing within the UK |
| Participant exclusion criteria | Dietary restrictions |
| Recruitment start date | 22/04/2020 |
| Recruitment end date | 30/04/2020 |
Locations
Countries of recruitment
- England
- United Kingdom
Study participating centre
Institute of Public Health
Cambridge
CB2 0SR
United Kingdom
Sponsor information
University/education
Greenwich House
Madingley Rd
Cambridge
CB3 0TX
England
United Kingdom
| Phone | +44 (0)1223333543 |
|---|---|
| research_governance@medschl.cam.ac.uk | |
| Website | http://www.cam.ac.uk/ |
"ROR" |
https://ror.org/013meh722 |
Funders
Funder type
Research organisation
Private sector organisation / International organizations
- Location
- United Kingdom
Results and Publications
| Intention to publish date | 31/12/2020 |
|---|---|
| Individual participant data (IPD) Intention to share | No |
| IPD sharing plan summary | Data sharing statement to be made available at a later date |
| Publication and dissemination plan | 1. Planned submission of the main results of this study for publication in a peer-reviewed journal 2. Dissemination of the results to the public, policymakers and other researchers through targeted social media |
| IPD sharing plan | The data-sharing plans for the current study are unknown and will be made available at a later date |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Results article | 30/04/2022 | 27/10/2022 | Yes | No |
Editorial Notes
27/10/2022: Publication reference added.
07/01/2021: The following changes were made to the trial record:
1. The contact details were updated.
2. The plain English summary was updated to reflect these changes.
20/05/2020: The total final enrolment number has been added.
