Reminder Strategies to Improve Meal-Logging Adherence
1 other identifier
interventional
200
1 country
1
Brief Summary
This study is a single-center micro-randomized trial, aiming to examine the effects of two theory-driven reminder strategies on adherence to repeated, image-based meal logging in adults age 45 and older. Three times daily, participants are automatically randomized to receive one of three reminder messages prior to each habitual mealtime. The main research questions the trial aims to answer are:
- Do loss-framed reminders (emphasizing loss of a daily financial reward for not logging) increase meal logging adherence in the two hours following a reminder, compared to a neutral reminder?
- Do logging consistency reminders (providing feedback on recent logging streaks) increase meal logging adherence in the two hours following a reminder, compared to a neutral reminder?
- Do the effects of loss-framed and logging consistency reminders differ from each other? Primary aim: To estimate the proximal effect of each reminder type on whether a participant logs a meal within two hours of receiving a reminder. Secondary aim: To examine whether within-person physiological patterns (e.g., heart rate variation) moderate response to reminders, with the goal of identifying physiological markers of receptivity to behavioral prompts. The trial aims to enroll 200 adults aged 45 and older. Participants attend a baseline visit for onboarding, consent, and device setup, followed by a 28 day remote intervention period during which they should photograph their meals three times daily (breakfast, lunch, dinner) and wear a smartwatch and smart ring continuously. Prior to each mealtime, they receive an automatically randomized reminder message. Participants earn a daily financial reward contingent on completing meal logging for that day. Note: This trial was registered retrospectively as enrollment began prior to registration. However, registration was completed before data collection was finished and before any data analysis was conducted.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for not_applicable
Started Dec 2025
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
Click on a node to explore related trials.
Study Timeline
Key milestones and dates
Study Start
First participant enrolled
December 8, 2025
CompletedFirst Submitted
Initial submission to the registry
April 21, 2026
CompletedFirst Posted
Study publicly available on registry
April 29, 2026
CompletedPrimary Completion
Last participant's last visit for primary outcome
January 1, 2027
ExpectedStudy Completion
Last participant's last visit for all outcomes
January 1, 2027
May 5, 2026
April 1, 2026
1.1 years
April 21, 2026
April 28, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (1)
Meal Logging Adherence
Proportion of decision points at which a participant logs a meal within 2 hours of receiving a reminder, compared across reminder types (loss-framed, logging consistency, and neutral control).
Within 2 hours of each decision point, assessed over 28 days
Secondary Outcomes (1)
Moderators of Reminder Responsiveness
Assessed over 28 days
Study Arms (3)
Loss-Framed Reminder
EXPERIMENTALA push notification emphasizing the loss of a daily financial reward for not logging the upcoming meal. Assigned with 1/3 probability at each decision point.
Logging Consistency Reminder
EXPERIMENTALA push notification providing feedback on the participant's recent meal logging streak. Assigned with 1/3 probability at each decision point.
Neutral Reminder (Active Control)
ACTIVE COMPARATORA push notification reminding the participant to log a meal without loss-framing or consistency feedback. Serves as the reference condition against which the two experimental reminders are compared. Assigned with 1/3 probability at each decision point.
Interventions
Push notification emphasizing loss of daily financial reward for not logging the upcoming meal.
Push notification providing feedback on recent meal logging streak.
Push notification reminding participants to log a meal.
Eligibility Criteria
You may qualify if:
- Citizens or residents of Switzerland who are German-speaking (main place of living or employment in Switzerland).
- Age ≥45 years.
- BMI ≥25 kg/m² (overweight or obese).
- Regular access to a smartphone (iOS or Android) with a data plan.
- Able to use smartphone applications.
- Able to walk independently.
You may not qualify if:
- History of stroke, heart disease, renal failure, cancer, or diabetes (type 1 or type 2).
- Past vascular bypass surgery or angioplasty.
- Current or planned use of glucose-lowering medications during the upcoming 4 weeks (e.g., GLP-1 receptor agonists, metformin).
- Pregnant or breastfeeding.
- Relevant skin conditions at wearable placement sites (e.g., upper arm).
- BMI \<25 kg/m² confirmed at enrollment.
- FPG ≥7.0 mmol/L and/or HbA1c ≥6.5% (newly identified type 2 diabetes); Individuals who meet type-2 diabetes criteria at enrollment, based on Swiss/ADA diagnostic criteria will be informed of blood test results and referred to a GP. These individuals will be deemed ineligible and excluded from the study.
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
HOCH Health and School of Medicine, University of St. Gallen
Sankt Gallen, Canton of St. Gallen, 9000, Switzerland
MeSH Terms
Conditions
Condition Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- not applicable
- Allocation
- RANDOMIZED
- Masking
- NONE
- Purpose
- OTHER
- Intervention Model
- SEQUENTIAL
- Sponsor Type
- OTHER
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
April 21, 2026
First Posted
April 29, 2026
Study Start
December 8, 2025
Primary Completion (Estimated)
January 1, 2027
Study Completion (Estimated)
January 1, 2027
Last Updated
May 5, 2026
Record last verified: 2026-04