A Health App Using Recipes and Education Components to Facilitate Sustainable and Healthier Diets.

Feasibility and Acceptability of a Digital Health App to Facilitate More Sustainable and Healthier Diets: Protocol for a Pilot Trial.

This study is a pilot trial of a smartphone app to promote sustainable and healthy eating, running for 10 weeks. The app aims to promote general wellbeing in the working population. The investigators are interested in the feasibility and acceptability of the plant-based recipes and information pages, so the focus will be on how people engage with these features and how they meet their needs.

Participants will be randomised into three groups:

1. General information (no app).
2. Standard app (app as it stands).
3. Enhanced app with recipes and behaviour change recommendations (app + messages).

Data on demographics and food choice will be collected at the start and end of the intervention. A subset of participants will also take part in short interviews to talk about their experiences.

Study Overview

• Status: Completed
• Conditions: Nutrition; Sustainability; Mobile Health Technology (mHealth)
• Intervention / Treatment: Behavioral: General information; Device: App; Device: App + messages

Detailed Description

Overall aim:

This pilot trial aims to understand the feasibility and acceptability of a health and wellbeing app. The main focus is around the plant-based recipes and information pages delivered through the chat functionality.

Specific objectives:

The primary objective is to understand the feasibility and acceptability of setting up and running a trial with the app, focusing on the reach, adoption, implementation, and maintenance. The secondary objectives are to explore the indicative efficacy of the app in facilitating more sustainable and healthier diets, measured by a change in meat and legume intake, to what extent the recipes and information pages contribute to this effect, and whether there is a relationship between the self-perceived capabilities, opportunities and motivations to consume a sustainable and healthier diet.

Intervention:

The overall aim of the app is to enhance general wellbeing. The information pages contain general information on certain aspects of diets for health and sustainability. The recipes are available for breakfast, lunch and dinner, and vary in their composition of healthy and sustainable foods.

Sample size:

The target sample size will be 99 (33 per arm), which will account for the possibility of 40% dropout in the first two weeks, which is typical for smartphone apps, and would still suffice the rule of thumb for 25 per group to be included in a pilot study to yield a small standardised effect size.

Outcomes:

Outcomes (and data) that will be collected and include 1) programme reach (population characteristics), 2) adoption of the app (participation and retention rates), 3) acceptability of the intervention (engagement with and usefulness of the app features), 4) implementation of delivering the intervention (compliance), 5) maintenance of the intervention (participant and organizational sustainability), and 6) efficacy of the intervention (indications of change in behavioural determinants and behaviours).

• Study Type: Interventional
• Enrollment (Actual): 147
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom
    • London School of Hygiene & Tropical Medicine

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Have a personal (not work) smartphone
• Have access to WiFi at home
• Have an out-of-home data package
• Be 18 years of age or older

Exclusion Criteria:

• Underweight for their age and gender
• Follow a restrictive diet (e.g., pregnant, breastfeeding, food intolerant/allergic, attempting to lose weight, diabetes, cardiovascular disease, or other long-term disease including eating disorders)
• Have a mental disability or learning difficulty

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control group	Behavioral: General information; The (no app) control group will be sent general health and sustainability information via email immediately after randomisation is done. To incentivise participation in both baseline and follow-up assessments, the control group will be offered lifetime access to the app and a summary of their self-reported food intake at week 10. The control group will be sent one email reminder halfway through (week 5) to remind them that they are involved in the study, provide them with instructions on the follow-up assessment, and that they will receive the intervention and dietary feedback at week 10.
Experimental: Intervention group 1	Device: App; As the app has not been evaluated before in terms of its impact on dietary change, the first intervention group will have the app as it stands. The overall aim of the app is to improve general wellbeing across several health-related domains, which is achieved through engaging with its main features (the daily plan, journal, user profile, and chat function).
Experimental: Intervention group 2	Device: App + messages; The plant-forward recipes and information pages available on the app will be made more salient for app users in this group through sending them via targeted messages in the chat function at specific times. Each day, the information pages will be sent at 09:30 and the recipes will be sent at 13:00.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adherence to intervention	Number of days participants log on to the app, measured using the app analytics	From enrolment to the end of the intervention at 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in legume intake	Self-reported dietary intake from two 24h dietary recalls, averaged into portions per day	Enrolment and at the end of the intervention at 8 weeks
Change in meat intake	Self-reported dietary intake from two 24h dietary recalls, averaged into portions per day	Enrolment and at the end of the intervention at 8 weeks

Collaborators and Investigators

• Sponsor: London School of Hygiene and Tropical Medicine

Study record dates

Study Major Dates

• Study Start (Actual): February 5, 2025
• Primary Completion (Actual): July 14, 2025
• Study Completion (Actual): July 14, 2025

Study Registration Dates

• First Submitted: February 10, 2025
• First Submitted That Met QC Criteria: February 18, 2025
• First Posted (Actual): February 19, 2025

Study Record Updates

• Last Update Posted (Actual): March 10, 2026
• Last Update Submitted That Met QC Criteria: March 6, 2026
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Keywords: Feasibility; Randomised controlled trial; Nutrition; mHealth; Diet; Intervention; Acceptability; Pilot trial; Healthy eating; Sustainability; Behaviour change; Sustainable diets; Mobile apps; Recipe analysis
• Other Study ID Numbers: 28317; 204000 (Other Grant/Funding Number: NIHR)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The investigators plan to upload IPD and related data dictionaries available on LSHTM's data repository called Data Compass.
• IPD Sharing Time Frame: Beginning 3 months and ending 10 years after the publication of results.
• IPD Sharing Access Criteria: The data will be provided to other researchers for use in secondary research upon reasonable request through LSHTM's Data Compass repository. The provision of data will be subject to information being provided on the research objectives and ethics status of the project. Ethical approval will need to be sought before receiving the data.
• 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
• product manufactured in and exported from the U.S.: No