Nutri-score Labelling in a UK Restaurant Setting: a Randomised Control Trial

An experiment exploring the perceived effectiveness of Nutri-score food labels with calorie labelling compared to calorie labelling only on food choice and consumption in a real-world setting

Study Overview

• Status: Completed
• Conditions: Food Labelling; Food Choice; PME
• Intervention / Treatment: Behavioral: menu labelling type

• Study Type: Interventional
• Enrollment (Actual): 672
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Merseyside
    • Liverpool, Merseyside, United Kingdom, L69 7ZA
      • University of Liverpool

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Can visit a restaurant in Liverpool city centre
• Regularly eat food prepared out of the home (from restaurants, cafes, fast food etc., at least once a month)
• Over the age of 18 years
• Fluent English speaker

Exclusion Criteria:

• Pregnant/breastfeeding
• You have been diagnosed with a current or historic eating disorder

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Restaurant 1; Restaurant 1: plant-based cafe	Behavioral: menu labelling type; Participants will be given a restaurant's menu with calorie information or a menu with calorie information and NS labelling.
Active Comparator: Restaurant 2; Restaurant 2: University cafe	Behavioral: menu labelling type; Participants will be given a restaurant's menu with calorie information or a menu with calorie information and NS labelling.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Perceived Message Effectiveness	An adapted version of the University of North Carolina PME scale will be used to measure health concern, product attitude, and discouragement of item consumption in response to the food menu. Participants will be given the menu they ordered from to look at. All participants will answer 3 questions using a Likert scale ranging from 1 - 5 anchored by "not at all" and "a great deal". The mean response to the three items will be calculated. PME is used as an early indicator of a health message's potential to change behaviour (e.g., reduce selection of less healthy items). The scale has been used previously to identify the potential impact of food labels and is predictive of long-term behaviour.	Up to 30 weeks
Nutritional quality of each item and for the full meal	Nutritional quality for meal choices will be calculated using the UK NPM scoring system. This calculates a score (continuous variable) for a product by deducting a total score for positive nutrients from a total score for negative nutrients. A lower score represents greater nutritional quality and a higher score represents poorer nutritional quality. We will calculate the mean NPM score weighted by energy content of items for each participant. This will ensure that the NPM score of main dishes will be weighted higher than that of starters or sides (assuming energy content of selected main is higher than any starters or sides), leading to a more representative overall NPM score for food orders. This will be done using the weighted.mean function in R. This function multiplies each value (i.e. NPM scores for individual items) by its corresponding weight (kcal content of individual items), sums all items and then divides this by the sum of the weights.	Up to 30 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
NS label of each item selected	A NS category value will be recorded for each item selected by participants (A,B,C,D,E)	Up to 30 weeks
Energy content of all food ordered	The sum of energy (kcal) across all foods ordered for the meal will be calculated	Up to 30 weeks
Energy and nutrients consumed	Researchers will take pictures of plates before and after each item is given to participants. Researchers will estimate the percentage of each dish consumed. Participants will be asked whether they shared any of their meal with someone else and this will be taken into account when making percentage estimates. A random 10% of percentage estimates will be performed by a second researcher to measure reliability. Energy and nutrient consumption will be calculated by multiplying the total energy/nutritional content of food items selected/consumed by the estimated proportion of the item consumed. Nutrients explored will be salt, sugar, fat, saturated fat, protein and fibre.	Up to 30 weeks
Later intake	The morning after participants take part in the study, they will be emailed with a link to complete a dietary recall survey (via intake 24, https://intake24.co.uk/). Participants will report everything they ate after the study session up until they went to bed. They will be asked to provide as much detail as possible on what they had for dinner, snacks, and drinks after the study session. We will estimate based on data from Intake 24, later consumption (kcal, salt, fat, saturated fat, sugar, protein, fibre).	Up to 30 weeks

Collaborators and Investigators

• Sponsor: University of Liverpool
• Collaborators: University of Bristol; Liverpool John Moores University
• Investigators: Principal Investigator: Eric Robinson, University of Liverpool

Study record dates

Study Major Dates

• Study Start (Actual): March 27, 2025
• Primary Completion (Actual): August 1, 2025
• Study Completion (Actual): August 1, 2025

Study Registration Dates

• First Submitted: March 26, 2025
• First Submitted That Met QC Criteria: April 10, 2025
• First Posted (Actual): April 11, 2025

Study Record Updates

• Last Update Posted (Actual): February 20, 2026
• Last Update Submitted That Met QC Criteria: February 18, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Food choice; PME; Nutri-score
• Other Study ID Numbers: NS in the OOHFS study

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymised participant data will be placed on the Open Science Framework in case other researchers want to use in the future.
• IPD Sharing Time Frame: IPD and supporting information will be available once the study is completed and published, with no end date.
• IPD Sharing Access Criteria: The IPD and supporting information will be uploaded to the Open Science Framework where it will be openly available.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No