Condition category
Nutritional, Metabolic, Endocrine
Date applied
22/01/2020
Date assigned
27/01/2020
Last edited
27/05/2020
Prospective/Retrospective
Prospectively registered
Overall trial status
Completed
Recruitment status
No longer recruiting

Plain English Summary

Background and aims
Alongside tobacco, excess consumption of alcohol and energy-dense foods are two of the most significant preventable causes of a range of non-communicable diseases globally, including heart disease and many cancers. Changing cues in the immediate physical environments that influence consumption could contribute to reducing excess food and alcohol consumption. One intervention that has received considerable attention towards achieving this is altering the size of tableware, including plates and glasses, and packaging, including bottles. The current study focuses on selection - self-serving and self-pouring – of food and wine, an immediate, reliable predictor of consumption. The study aims are to estimate the impact of plate size and shape on the amount of food that is self-served, and the size of wine glasses and wine bottles on the amount of wine that is self-poured.

Who can participate?
Adults over the age of 18, who drink wine and eat rice at least monthly.

What does the study involve?
Participants will provide written informed consent to participate in both interventions that form part of this study. They will be given a cover story that the study is examining how different plates and glasses can affect the visual appeal and attractiveness of food and drink. Participants will first complete demographic measures (age, sex, education). They will then be randomised to the order in which they complete Intervention 1 and 2. The order of randomisation will be concealed from the researcher until consent has been given - at this point they will access the randomisation schedule.
For Intervention 1, participants will be randomised to one of 720 possible sequences in which plate size and shape conditions can be presented. Participants will first be presented with a short context-setting vignette and for each plate condition they will be asked to self-serve their typical amount of food (i.e. “Imagine the most typical setting in which you serve yourself a meal. Please serve your typical amount”) from a serving dish containing more than can be served on to the largest plate (between 1-1.5kg). Each portion of self-served food will be weighed (by weighing the remaining food in the serving bowl) and the serving dish will be re-filled between serving sessions, to ensure the amount of food remains constant across conditions. Each plate will be presented separately with all other plates kept hidden during each self-serving session. The study food will be a microwaveable rice meal prepared each day that the study runs.
For Intervention 2, participants will be randomised to one of 12 possible sequences in which wine glasses and bottles of different sizes are presented. Participants will first be presented with a short context-setting vignette (i.e. “Imagine the most typical occasion in which you pour yourself wine. Please pour your typical amount”) and for each glass/bottle condition they will be asked to self-serve a typical amount from the provided bottle. Each portion of self-served wine will be measured (by weighing the remaining wine in the bottle) and the bottles re-filled between serving sessions, to ensure the amount of wine remains constant across conditions. Each glass will be presented separately with all other glasses kept hidden during each self-serving session. Similarly, each bottle will be presented separately.
After completing both interventions, participants will complete further demographic measures (height, weight) and the debrief measures, before being told the true purpose of the study. Participants will then be reimbursed ~30GBP for their time.

What are the possible benefits and risks of participating?
Participants will be paid standard market research panel rates for participating in this study. There are no known risks of participating in the 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?
October 2019 to March 2020

Who is funding the study?
Wellcome Trust (UK)

Who is the main contact?
Dr Natasha Clarke
ncc42@medschl.cam.ac.uk

Trial website

Contact information

Type

Scientific

Primary contact

Dr Natasha Clarke

ORCID ID

http://orcid.org/0000-0003-2375-4510

Contact details

Behaviour and Health Research Unit
University of Cambridge
Institute of Public Health Forvie Site
Robinson Way
Cambridge
CB2 0SR
United Kingdom
+44 (0)1223 762565
ncc42@medschl.cam.ac.uk

Additional identifiers

EudraCT number

Nil known

ClinicalTrials.gov number

Nil known

Protocol/serial number

v2.1

Study information

Scientific title

Size and shape of plates and size of wine glasses and bottles: impact on selection of food and alcohol

Acronym

Tableware study

Study hypothesis

Intervention 1: plate size and shape
1. As plates increase in size, an increasing amount of food is self-served on to them
There is insufficient evidence for a directional hypothesis for plate shape

Intervention 2: wine glass size and wine bottle size
1. As wine glasses increase in size, an increasing amount of wine is self-poured
2. More wine is self-poured from larger bottles compared with smaller bottles
3. The effect of increasing bottle size is more marked for larger glasses than it is for smaller glasses

Ethics approval

Approved 14/01/2020, Cambridge Psychology Research Ethics Committee (School of the Biological Sciences, University of Cambridge, 17 Mill Lane, Cambridge CB2 1RX; +44 (0)1223 766894; Cheryl.Torbett@admin.cam.ac.uk), ref: PRE.2019.058

Study design

Intervention 1:
Within-subjects factorial design with six conditions: 3 plate sizes (small, medium, large) x 2 plate shapes (circular; square). Participants will be randomised to the order of plates onto which they will self-serve food, determined by simple randomisation.

Intervention 2:
Within-subjects factorial design with six conditions: 3 glass sizes (29cl; 35cl; 45cl) x 2 bottle sizes (75cl; 50cl). Participants will be randomised to the order in which they free-pour from each of the bottles into each of the glasses, using simple randomisation.

Primary study design

Interventional

Secondary study design

Randomised cross over trial

Trial setting

Other

Trial type

Other

Patient information sheet

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

Condition

Food and alcohol consumption

Intervention

Intervention 1 – Plate size and shape
Plate sizes
Three different size plates will be used in the study differing in surface areas:
1. Small: 254.5 cm2
2. Medium: 415.5 cm2
3. Large: 683.5 cm2
The surface areas will be kept constant between plates of same sizes but different shapes. Surface areas correspond to circular and square plates as follows: 254.5 cm2: 18 cm diameter circular; 16 cm square; 415.5 cm2: 23 cm diameter circular; 20.4 cm square; 683.5 cm2: 29.5 cm diameter circular; 26.1 cm square. The set of sizes is informed by the sizes of circular plates previously used in a lab study (Kosite et al, 2019) (23 cm and 29 cm).

Plate shapes
Two different shapes of plates will be used in the study:
1. Round
2. Square
Square plates will be matched in surface area to round plates (see above).
All plates used will be of a similar design, made from white bone china, unlined and unpatterned – with custom-made plates made as necessary (Round plates: China by Denby Dinner Plate [large], China by Denby Dessert/Salad Plate [medium], China by Denby Tea Plate [small]; Square plates: Bennett Square Dinner Plate [large], Bennett Square Plate Salad Plate [medium], Custom Made by Reiko Kaneko [small]).

Intervention 2 - Wine glass size and wine bottle size
Glass sizes
Three sizes of wine glasses will be used in the study with capacities of:
1. 290 ml (small)
2. 350 ml (medium)
3. 450 ml (large)
This set of sizes is informed by recent field studies (Clarke et al., 2019). All glasses will be of the same design (Royal Leerdam Bouquet).

Bottle sizes
Two wine bottle sizes will be used in the study:
1. 50 cl
2. 75 cl
The set of bottle sizes is informed by a recent randomised controlled trial assessing the impact of bottle size on in-home wine consumption (Codling, Mantzari et al., under review). Both bottles will be labelled as containing the same wine, using a branded bottle to increase ecological validity (Isla Negra Sauvignon Blanc). The grape variety is chosen on the basis of it being the most popular in the UK. The brand is chosen based on it being available in both 50 cl and 75 cl sizes and in bottles of identical design, i.e. shape and colour.

Participants will provide written informed consent to participate in both interventions that form part of this study. They will be given a cover story that the study is examining how different plates and glasses can affect the visual appeal and attractiveness of food and drink. Participants will first complete demographic measures (age, sex, education). They will then be randomised to the order in which they complete Intervention 1 and 2. The order of randomisation will be concealed from the researcher until consent has been given - at this point they will access the randomisation schedule.

For Intervention 1, participants will be randomised to one of 720 possible sequences in which plate size and shape conditions can be presented. Participants will first be presented with a short context-setting vignette and for each plate condition they will be asked to self-serve their typical amount of food (i.e. “Imagine the most typical setting in which you serve yourself a meal. Please serve your typical amount”) from a serving dish containing more than can be served on to the largest plate (between 1-1.5 kg). Each portion of self-served food will be weighed (by weighing the remaining food in the serving bowl) and the serving dish will be re-filled between serving sessions, to ensure the amount of food remains constant across conditions. Each plate will be presented separately with all other plates kept hidden during each self-serving session. The study food will be a microwaveable rice meal prepared each day that the study runs.

For Intervention 2, participants will be randomised to one of 12 possible sequences in which wine glasses and bottles of different sizes are presented. Participants will first be presented with a short context-setting vignette (i.e. “Imagine the most typical occasion in which you pour yourself wine. Please pour your typical amount”) and for each glass/bottle condition they will be asked to self-serve a typical amount from the provided bottle. Each portion of self-served wine will be measured (by weighing the remaining wine in the bottle) and the bottles re-filled between serving sessions, to ensure the amount of wine remains constant across conditions. Each glass will be presented separately with all other glasses kept hidden during each self-serving session. Similarly, each bottle will be presented separately.

After completing both interventions, participants will complete further demographic measures (height, weight) and the debrief measures, before being told the true purpose of the study. Participants will then be reimbursed ~30GBP for their time.

Intervention type

Behavioural

Phase

Drug names

Primary outcome measure

Intervention 1: the amount of food (in grams) self-served, measured by weighing the remaining food in the serving bowl
Intervention 2: the amount of wine (in millilitres) self-poured, measured weighing the remaining wine in the bottle

Measured at a single timepoint

Secondary outcome measures

There are no secondary outcome measures

Overall trial start date

01/10/2019

Overall trial end date

17/03/2020

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. 18 + years
2. Able to read and write in English
3. Eat rice and drink white wine occasionally (at least once a month for both)

Participant type

Healthy volunteer

Age group

Adult

Gender

Both

Target number of participants

279

Total final enrolment

140

Participant exclusion criteria

1. Drinks wine or eats rice less than monthly
2. Under 18

Recruitment start date

03/02/2020

Recruitment end date

17/03/2020

Locations

Countries of recruitment

United Kingdom

Trial participating centre

Roots Research
50 Grand Parade
Brighton
BN2 9QA
United Kingdom

Sponsor information

Organisation

University of Cambridge

Sponsor details

Greenwich House
Madingley Road
Cambridge
CB3 0TX
United Kingdom
+44 (0)1223333543
Research_Governance@medschl.cam.ac.uk

Sponsor type

University/education

Website

http://www.cam.ac.uk/

Funders

Funder type

Charity

Funder name

Wellcome Trust

Alternative name(s)

Funding Body Type

private sector organisation

Funding Body Subtype

International organizations

Location

United Kingdom

Results and Publications

Publication and dissemination plan

1. The protocol is available on the OSF framework and will be registered – under embargo until after data collection - on the OSF (https://osf.io/dj3c6//), the analysis plan will also be registered before data collection begins under the same project
2. Planned submission of the main results of this study for publication in a peer-reviewed journal
3. Dissemination of the results to the public, policymakers and other researchers through targeted social media

IPD sharing statement
The anonymised raw data will be made available on the OSF and the university repository, along with the analysis plan which will be registered before the researchers analyse the data on the OSF. Consent from participants was obtained.

Intention to publish date

01/09/2020

Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

27/05/2020: IPD sharing statement added. 15/05/2020: The following changes were made to the trial record: 1. The recruitment end date and overall trial end date were changed from 01/05/2020 to 17/03/2020. 2. The total final enrolment number was added. 9/04/2020: Due to current public health guidance, recruitment for this study has been paused. 24/01/2020: Trial's existence confirmed by Cambridge Psychology Research Ethics Committee.