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Completed

NCT Number: NCT06833736

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

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.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

London School of Hygiene & Tropical Medicine

London, United Kingdom

About this study

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).

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

App

Device

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).

App + messages

Device

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.

General information

Behavioral

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.

Primary outcomes

  1. Adherence to intervention

    Time frame: From enrolment to the end of the intervention at 8 weeks

    Number of days participants log on to the app, measured using the app analytics

Secondary outcomes

  1. Change in legume intake

    Time frame: Enrolment and at the end of the intervention at 8 weeks

    Self-reported dietary intake from two 24h dietary recalls, averaged into portions per day

  2. Change in meat intake

    Time frame: Enrolment and at the end of the intervention at 8 weeks

    Self-reported dietary intake from two 24h dietary recalls, averaged into portions per day

Sponsors and collaborators

Lead sponsor

London School of Hygiene and Tropical Medicine

Other

Registry information

Official study title

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

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Feb 19, 2025
Registry last updated
Mar 10, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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