Real-World Two-Year Weight Loss Outcomes With Breath Biofeedback

NCT07430618 | Completed

• 1 other identifier: 20260202
• Study Type: observational
• Target: 11,524
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this retrospective observational study is to evaluate the real-world durability of weight loss among adults with overweight or obesity who used the Key to Health breath-biofeedback mHealth program. The main questions it aims to answer are:

1. 1.What is the mean percent total body weight loss (TBWL%) at 104 weeks after program start?
2. 2.What are the TBWL% estimates at 12, 24, and 52 weeks, and what proportion of users achieve clinically meaningful weight loss (≥5% and ≥10%) at 52 and 104 weeks (observed case)?

Conditions

Overweight (BMI > 25); Obesity (Body Mass Index >30 kg/m2); Obesity & Overweight

Keywords

Overweight; Obesity; Breath sensor; Biofeedback; Digital Health; Weight loss; Weight management

Outcome Measures

Primary Outcomes (1)

• Percent Total Body Weight Loss (TBWL%) at Week 104.

  TBWL% at Week 104 is defined as: (post-baseline weight - baseline weight) / baseline weight × 100, where baseline weight is the self-reported onboarding weight. The Week-104 weight is the post-baseline weight entry closest to Day 728 within the prespecified visit window (Days 668-788; earlier selected if equidistant).

  Week 104 (target Day 728; visit window Days 668-788 after program start).

Secondary Outcomes (11)

• Percent Total Body Weight Loss (TBWL%) at Week 52

  Week 52 (target Day 364; visit window Days 334-394)

• Percent Total Body Weight Loss (TBWL%) at Week 24

  Week 24 (target Day 168; visit window Days 138-198)

• Percent Total Body Weight Loss (TBWL%) at Week 12

  Week 12 (target Day 84; visit window Days 69-99)

• Proportion Achieving ≥5% Weight Loss at Week 52 (Observed Case)

  Week 52 (target Day 364; visit window Days 334-394)

• Proportion Achieving ≥10% Weight Loss at Week 52 (Observed Case)

  Week 52 (target Day 364; visit window Days 334-394)

Study Arms (1)

Key to Health Program Users (Commercial Cohort)

Adults with overweight or obesity who enrolled in and used the Key to Health breath-biofeedback mHealth weight-loss program during the data collection window and had a valid onboarding baseline weight plus at least one post-baseline weight entry recorded via the app and/or a connected scale.

Device: Breath acetone biofeedback device with mHealth program

Interventions

Breath acetone biofeedback device with mHealth program DEVICE

A breath acetone biofeedback device used alongside the Key to Health mobile app as part of a comprehensive weight-loss program. Users obtain breath acetone readings via the device and record body weight via manual entry and/or connected scale. The app provides program resources to support behavior change, including a food database/food logging tools, nutrition and exercise education (lessons, articles, and other content), alerts/notifications, and engagement features (e.g., streaks and progress tracking). This study retrospectively analyzes de-identified data generated during routine program use; no study-specific procedures are administered.

Also known as: Key to Health Breath Sensor, Key to Health Program, Keyto Breath Acetone Device, Keyto Breath Acetone Sensor

Key to Health Program Users (Commercial Cohort)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Commercial users of the Key to Health digital weight loss program (mobile app) who enrolled and used the program during the data collection window. Users are members of the general community who accessed the program through routine commercial availability (direct-to-consumer), and who recorded weight measurements during typical use of the app and/or a connected scale. De-identified backend program data were used for this retrospective analysis.

You may qualify if:

• Adults aged ≥18 years at program start/onboarding
• Program start date between November 2018 and April 2023
• Valid baseline (onboarding) self-reported weight recorded
• Baseline BMI \>25 kg/m²
• At least one valid post-baseline weight entry recorded after onboarding (manual and/or connected scale)

You may not qualify if:

• Missing or invalid baseline weight
• Biologically implausible baseline weight (per prespecified data-quality checks)
• No post-baseline weight data recorded after the baseline date/onboarding timestamp

Sponsors & Collaborators

• University of British Columbia: lead

Study Sites (1)

UBC Okanagan

Kelowna, British Columbia, V1V 1V7, Canada

Location

Related Publications (3)

• Falkenhain K, Lowe DA, Locke SR, Singer J, Weiss EJ, Little JP. Long-Term Weight Loss in Adults With Overweight or Obesity Using a Breath Biofeedback mHealth App: A One-Year Follow-Up of a Randomized Trial. Obes Sci Pract. 2025 Dec 5;11(6):e70106. doi: 10.1002/osp4.70106. eCollection 2025 Dec.

  PMID: 41356752 BACKGROUND

• Falkenhain K, Locke SR, Lowe DA, Lee T, Singer J, Weiss EJ, Little JP. Use of an mHealth Ketogenic Diet App Intervention and User Behaviors Associated With Weight Loss in Adults With Overweight or Obesity: Secondary Analysis of a Randomized Clinical Trial. JMIR Mhealth Uhealth. 2022 Mar 14;10(3):e33940. doi: 10.2196/33940.

  PMID: 35285809 BACKGROUND

• Falkenhain K, Locke SR, Lowe DA, Reitsma NJ, Lee T, Singer J, Weiss EJ, Little JP. Keyto app and device versus WW app on weight loss and metabolic risk in adults with overweight or obesity: A randomized trial. Obesity (Silver Spring). 2021 Oct;29(10):1606-1614. doi: 10.1002/oby.23242. Epub 2021 Sep 14.

  PMID: 34124856 BACKGROUND

MeSH Terms

Conditions

Overweight; Obesity; Weight Loss

Condition Hierarchy (Ancestors)

Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Body Weight Changes

Study Officials

• Jonathan Little

  UBC Okanagan

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: February 17, 2026
• First Posted: February 24, 2026
• Study Start: November 18, 2018
• Primary Completion: April 25, 2025
• Study Completion: April 25, 2025
• Last Updated: February 24, 2026

Record last verified: 2026-02

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)