Condition category
Nutritional, Metabolic, Endocrine
Date applied
30/09/2015
Date assigned
30/09/2015
Last edited
30/09/2015
Prospective/Retrospective
Prospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Background and study aims
Prompting people with healthier alternative foods is a simple way to shift people towards buying healthier food, and has been used in a number of healthy eating campaigns. Recent work has explored the impact of offering automatically-selected lower-calorie swaps on an experimental supermarket website. This study found no overall effects of swaps, due to participants often not accepting the swaps or accepting swaps with a smaller reduction in calories. Those people who accepted more swaps did show reductions in the calories of their purchases. The current study aims to extend this work by testing whether framing the swap without appealing to health, instead using cost or social norms, might improve swap acceptance, and the impact of combining two of these frames.

Who can participate?
People aged 18-80 who are responsible for “about half” or “all or most” of the food/grocery shopping.

What does the study involve?
All participants are asked to shop for 10 items in an online supermarket shopping situation using an experimental website. At the end of the shopping task participants are presented with swaps offering healthier food choices, which are also cheaper than the initially selected item. Participants are randomly allocated to one of three groups, with each group using one of the following three phrases to offer the swaps:
1. “Swap to save calories”
2. “Swap to save money”
3. “Swap to this product chosen by customers who buy similar groceries to you”

What are the possible benefits and risks of participating?
Participants are unlikely to gain or lose anything from participating in the study.

Where is the study run from?
Behaviour and Health Research Unit, Cambridge University (UK).

When is study starting and how long is it expected to run for?
The study will run for 1 week in October 2015.

Who is funding the study?
Public Health England (UK).

Who is the main contact?
Anna Sallis
anna.sallis@phe.gov.uk


Trial website

Contact information

Type

Scientific

Primary contact

Miss Anna Sallis

ORCID ID

Contact details

80 London Road
London
SE1 6LH
United Kingdom

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Message framing for uptake of within-category healthy food swaps: an experimental online supermarket study across socio-economic groups

Acronym

Study hypothesis

1. Swaps framed in terms of the cost benefit or social norms are more likely to be accepted than swaps framed in terms of health benefit
2. Swaps framed in terms of cost are more accepted by individuals in low socioeconomic status (SES) groups whereas swaps framed in terms of health are more accepted by those in high SES groups

Ethics approval

Cambridge Psychology Research ethics committee, 03/09/2015, PRE 2015 056

Study design

Three-arm randomised controlled trial

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Internet

Trial type

Other

Patient information sheet

Condition

Online supermarket shopping

Intervention

The study will follow a between-subjects experimental design with three arms, assessing the impact of swap framing on swap acceptance. The effects will be compared with a simple health framing control. All participants are randomly allocated to one of three conditions. Groups will differ in the wording used at the top of the swap window.
1. Swap framed in terms of health alone (control): “Swap to save calories”
2. Swap framed in terms of cost alone: “Swap to save money”
3. Swap framed in terms of social norm alone: “Swap to this product chosen by customers who buy similar groceries to you”

Intervention type

Behavioural

Phase

Drug names

Primary outcome measures

Proportion accepted swaps: number of swaps accepted, number of swaps offered

Secondary outcome measures

1. Energy density (kJ per 100g) of the basket of goods purchased and the basket of original goods chosen, i.e. had swaps not been offered
2. Nutrient content of basket of goods purchased and of basket of original goods chosen including saturated fat, total sugar and salt
3. Acceptability of intervention – measured after completion of shopping.
4. Age
5. Gender
6. Self-reported weight
7. Self–reported height
8. SES: individual level – both highest educational qualification (UK census levels) and household income

Overall trial start date

01/10/2015

Overall trial end date

31/10/2015

Reason abandoned

Eligibility

Participant inclusion criteria

Participants will be recruited via a research agency and will cover a spread of socio-economic status ABC1 (53%), C2DE (47%), gender (50:50) and age (18 to 80). Screening questions will be used to ensure all participants are responsible for “about half” or “all or most” of the food/grocery shopping (UK national surveys indicate this to be the case for 73% of the population (Food Standards Agency, 2011)).

Participant type

Healthy volunteer

Age group

Adult

Gender

Both

Target number of participants

900

Participant exclusion criteria

Participants who are not responsible for “about half” or “all or most” of the food/grocery shopping

Recruitment start date

01/10/2015

Recruitment end date

08/10/2015

Locations

Countries of recruitment

United Kingdom

Trial participating centre

Public Health England
SE1 6LH
United Kingdom

Trial participating centre

Behaviour and Health Research Unit, Cambridge University
CB2 0SR
United Kingdom

Sponsor information

Organisation

Public Health England (UK)

Sponsor details

80 London Road
London
SE1 6LH
United Kingdom

Sponsor type

Government

Website

Funders

Funder type

Government

Funder name

Public Health England

Alternative name(s)

PHE

Funding Body Type

government organisation

Funding Body Subtype

Federal/National Government

Location

United Kingdom

Results and Publications

Publication and dissemination plan

Conferences and academic journals

Intention to publish date

30/03/2016

Participant level data

Not expected to be available

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes