Food SelectionNCT06458270
Salt Warning Label Restaurant Study
A study testing Salt warning label in people with Food Selection, run by University of Liverpool at 1 site in United Kingdom.
Trial summary
This between-subjects randomised controlled trial aims to test the effect of a menu featuring salt warning labels on perceived message effectiveness relative to a menu with no labels in a real-world restaurant environment. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Food Selection
- What is being tested?
- Salt warning label
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 465 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 3 Jun 2024to 14 Sep 2024
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Are a UK resident
- Are aged 18 years and above
- Are fluent in English
- Eat an out-of-home meal at least once a month on average
- Have no dietary allergies
- Are not vegan
Who cannot join
None listed.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
University of Liverpool
Liverpool, Merseyside, L69 7ZA
About this study
Official title: Perceived Effectiveness of Salt Warning Labels on a UK Restaurant Menu: a Real-world Pilot Experiment
This between-subjects randomised controlled trial aims to test the effect of a menu featuring salt warning labels on perceived message effectiveness relative to a menu with no labels in a real-world restaurant environment. The study will also act as a pilot experiment for examining the impact of the salt warning label on food choice and subsequent salt intake in real-world conditions.
Primary objectives:
Read more
- To measure the PME of a menu featuring salt warning labels relative to a menu with no labels
- To measure label awareness, perceived knowledge gain, and perceived influence of the label on food choice
Secondary objectives:
- To identify whether there is an effect of the salt warning label on:
- Food choice (label/no label)
- Total salt selected
- Total salt intake
- To examine support for the introduction of a salt warning label policy in the UK
- Conditions
- Food Selection
- Being tested
- Salt warning label
- Medical subject headings
- Food Preferences
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Salt warning labelBehavioural
A salt warning label will feature on the restaurant menu next to menu items that are high in salt (>3g, more than 50% of guideline daily amount [GDA] in the UK).
| Study group | Role | What they receive |
|---|---|---|
| Label group | Experimental | Participants will receive a manipulated restaurant menu featuring salt warning labels next to menu items that are high in salt. Receives: Behavioral: Salt warning label |
| Control group (no label) | No intervention | Participants will receive a standard restaurant menu (no labels). |
What is being measured
The primary outcome is the main question the study is designed to answer.
Perceived message effectiveness (PME)
Participants will answer 3 PME questions using a Likert scale ranging from 1 - 5 anchored by "not at all" and "a great deal": Prompt: "Think back to the menu that you ordered from…" "The menu made me concerned about the health effects of consuming items high in salt", "The menu made consuming items high in salt seem unpleasant", "The menu discouraged me from wanting to consume items high in salt". The mean response to the three items will be calculated.
Measured: Post - meal assessment (within 10 minutes)
Label awareness
"Did you notice any warning labels next to any of the menu items when making your meal selection?" (yes/no).
If [yes], "What did the label tell you about?" Response options: Healthy items, Organic, Calcium, Sustainable, Added sugars, Vegetarian, Unhealthy items, Salt, Fibre, Gluten Free, None of these, Not sure.
If [yes], "Please describe what the label said" (open text response). Responses that mention high in salt or similar will be coded as aware.
Measured: Post - meal assessment (within 10 minutes)
Salt awareness
"Did you think about the salt content of the meals when making your selection?" (yes/no)
Measured: Post - meal assessment (within 10 minutes)
Perceived knowledge gain
For this question, both conditions will be shown an image of the labelled menu. "Did you learn something new from the salt labels on the menu?" (yes/no).
Measured: Post - meal assessment (within 10 minutes)
Perceived influence
For this question, both conditions will be shown an image of the labelled menu, and some question phrasing is slightly altered.
"Did the salt label influence which food you ordered from the menu" (yes/no). "If [yes], how did the salt label influence your choice?" Response options: I avoided choosing a meal high in salt; I chose a meal high in salt; Other (free text response) Control: "Would the salt label have influenced what food you ordered from the menu?" (yes/no) If [yes], how would the salt label have influenced your choice? Response options: I would have avoided choosing a meal high in salt; I would have chosen a meal high in salt; Other (free text response)
Measured: Post - meal assessment (within 10 minutes)
Policy support
For this question, the both conditions will be shown an image of the labelled menu.
If the UK Government introduced policy requiring restaurant menu items high in salt to feature these labels, how would you feel?" Likert scale ranging from 1 - 5 anchored by "strongly oppose" and "strongly support".
Measured: Post - meal assessment (within 10 minutes)
Secondary outcomes (5)
Total salt purchased
Determined based on the total order of the participant, including food and drink. Prior to study commencement, all menu items will be sent for nutritional analysis to determine salt content/100g. Menu items will be weighed before being sent for analysis using kitchen scales (Vitafit VT706), so that specific salt content per serving can be calculated.
Measured: Post - meal assessment (within 10 minutes)
Labelled item selected
Determined based on whether the food item selected featured a high in salt warning label (yes = 1, no = 0).
Measured: Post - meal assessment (within 10 minutes)
Total salt consumed
Salt consumption will be determined from the order that the researcher takes and an estimation of the proportion of the meal that was consumed. The researcher will take a photograph before and after consumption and will estimate the percentage consumed component(s) of the meal, taking into account whether participants leave a proportion of all meal components or specific components (e.g., low salt or high salt components). Participants will also be asked whether they shared any of their meal with someone else. A random 10% selection of percentage estimates will be performed by a second researcher to measure reliability. Food consumption will then be calculated by subtracting an estimation of the proportion of the meal that was consumed (taking into account if any has been shared) from the food purchase.
Measured: Post - meal assessment (within 10 minutes)
Later salt intake
Participants will receive a link to a dietary recall questionnaire (Intake24, https://intake24.co.uk/) via email on the same day after taking part in the study, which they will be prompted to complete before bed. They will be asked to provide as much detail as possible on what they had for dinner, snacks, and drinks after the restaurant visit. Based on this information and salt values calculated by Intake24, the total salt consumed by the participants for the rest of the day after the visit will be estimated.
Measured: Follow-up assessment (next morning, 8AM, to be completed within 24 hours)
Other macronutrient intake
Total kcal, sugar, and saturated fat intake [i.e., other nutrients that are not the main warning focus] will be calculated based on the nutritional content of the order of the participant.
Measured: Post - meal assessment (within 10 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Jun 2024
- Study start3 Jun 2024
- Primary completion14 Sep 2024
- Study completion14 Sep 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Food SelectionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 465 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Liverpool
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute for Health Research, United Kingdom
- Responsible party
- Principal investigator, Eric Robinson, University of Liverpool
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06458270
- Sponsor's protocol ID
- rfj78drdsu52lsbw3kztnbpne8xdao
- Status last verified
- Mar 2025
- First submitted
- 3 Jun 2024
- Last updated
- 2 Apr 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The anonymised dataset has been uploaded to the Open Science Framework (OSF) - https://osf.io/whzc8/?view\_only=e97eb9ff6812457081d6d693e27bf1bd
Publications
Evans R, Brealey J, Clarke N, Falbe J, Finlay A, Jones A, Thorp P, Witham B, Witkam R, Robinson E. Salt warning labels in the out-of-home food sector: online and real-world randomised controlled trials in the UK. Lancet Public Health. 2025 Aug;10(8):e656-e667. doi: 10.1016/S2468-2667(25)00143-4.
PubMed 40738552
Study at a glance
From the registry record, last updated by the sponsor on 2 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Perceived Effectiveness of Salt Warning Labels on a UK Restaurant Menu: a Real-world Pilot Experiment
- ClinicalTrials.gov ID
- NCT06458270
- Acronym / sponsor ID
- rfj78drdsu52lsbw3kztnbpne8xdao
- Conditions
- Food Selection
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 465 participants (actual)
- Lead sponsor
- University of LiverpoolUniversity, hospital or other
- Collaborators
- National Institute for Health Research, United Kingdom
- Study start
- 3 Jun 2024 (actual)
- Primary completion
- 14 Sep 2024 (actual)
- Study completion
- 14 Sep 2024 (actual)
- First posted
- 13 Jun 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This between-subjects randomised controlled trial aims to test the effect of a menu featuring salt warning labels on perceived message effectiveness relative to a menu with no labels in a real-world restaurant environment. The study will also act as a pilot experiment for examining the impact of the salt warning label on food choice and subsequent salt intake in real-world conditions.
Primary objectives:
- To measure the PME of a menu featuring salt warning labels relative to a menu with no labels
- To measure label awareness, perceived knowledge gain, and perceived influence of the label on food choice
Secondary objectives:
- To identify whether there is an effect of the salt warning label on:
- Food choice (label/no label)
- Total salt selected
- Total salt intake
- To examine support for the introduction of a salt warning label policy in the UK
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Label group | Experimental | Behavioral: Salt warning labelParticipants will receive a manipulated restaurant menu featuring salt warning labels next to menu items that are high in salt. |
| Control group (no label) | No intervention | –Participants will receive a standard restaurant menu (no labels). |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Are a UK resident
- Are aged 18 years and above
- Are fluent in English
- Eat an out-of-home meal at least once a month on average
- Have no dietary allergies
Key exclusion criteria (0 listed)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Salt warning labelA salt warning label will feature on the restaurant menu next to menu items that are high in salt (>3g, more than 50% of guideline daily amount [GDA] in the UK). | Behavioural | Label group |
Primary outcome
Perceived message effectiveness (PME)
Time frame: Post - meal assessment (within 10 minutes)
Participants will answer 3 PME questions using a Likert scale ranging from 1 - 5 anchored by "not at all" and "a great deal": Prompt: "Think back to the menu that you ordered from…" "The menu made me concerned about the health effects of consuming items high in salt", "The menu made consuming items high in salt seem unpleasant", "The menu discouraged me from wanting to consume items high in salt". The mean response to the three items will be calculated.
Label awareness
Time frame: Post - meal assessment (within 10 minutes)
"Did you notice any warning labels next to any of the menu items when making your meal selection?" (yes/no). If [yes], "What did the label tell you about?" Response options: Healthy items, Organic, Calcium, Sustainable, Added sugars, Vegetarian, Unhealthy items, Salt, Fibre, Gluten Free, None of these, Not sure. If [yes], "Please describe what the label said" (open text response). Responses that mention high in salt or similar will be coded as aware.
Salt awareness
Time frame: Post - meal assessment (within 10 minutes)
"Did you think about the salt content of the meals when making your selection?" (yes/no)
Perceived knowledge gain
Time frame: Post - meal assessment (within 10 minutes)
For this question, both conditions will be shown an image of the labelled menu. "Did you learn something new from the salt labels on the menu?" (yes/no).
Perceived influence
Time frame: Post - meal assessment (within 10 minutes)
For this question, both conditions will be shown an image of the labelled menu, and some question phrasing is slightly altered. "Did the salt label influence which food you ordered from the menu" (yes/no). "If [yes], how did the salt label influence your choice?" Response options: I avoided choosing a meal high in salt; I chose a meal high in salt; Other (free text response) Control: "Would the salt label have influenced what food you ordered from the menu?" (yes/no) If [yes], how would the salt label have influenced your choice? Response options: I would have avoided choosing a meal high in salt; I would have chosen a meal high in salt; Other (free text response)
Policy support
Time frame: Post - meal assessment (within 10 minutes)
For this question, the both conditions will be shown an image of the labelled menu. If the UK Government introduced policy requiring restaurant menu items high in salt to feature these labels, how would you feel?" Likert scale ranging from 1 - 5 anchored by "strongly oppose" and "strongly support".
5 secondary outcomes
Total salt purchased
Time frame: Post - meal assessment (within 10 minutes)
Labelled item selected
Time frame: Post - meal assessment (within 10 minutes)
Total salt consumed
Time frame: Post - meal assessment (within 10 minutes)
Later salt intake
Time frame: Follow-up assessment (next morning, 8AM, to be completed within 24 hours)
Other macronutrient intake
Time frame: Post - meal assessment (within 10 minutes)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 2 Apr 2025.
- Derived from this study: PubMed 40738552Evans R, Brealey J, Clarke N, Falbe J, Finlay A, Jones A, Thorp P, Witham B, Witkam R, Robinson E. Salt warning labels in the out-of-home food sector: online and real-world randomised controlled trials in the UK. Lancet Public Health. 2025 Aug;10(8):e656-e667. doi: 10.1016/S2468-2667(25)00143-4.
- Individual participant dataSharing planned: Yes. The anonymised dataset has been uploaded to the Open Science Framework (OSF) - https://osf.io/whzc8/?view_only=e97eb9ff6812457081d6d693e27bf1bd
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Salt warning label in people with Food Selection, run by University of Liverpool at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 0 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 2 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Perceived message effectiveness (PME) (time frame: Post - meal assessment (within 10 minutes)). The study lists 6 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06458270, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Apr 2025.