Spark: Finding the Optimal Tracking Strategy for Weight Loss in a Digital Health Intervention

Optimizing Self-monitoring in a Digital Health Intervention for Weight Loss

This optimization trial will examine three tracking (or "self-monitoring") strategies for weight loss -- tracking dietary intake, steps, and/or body weight -- all delivered through digital health tools. The purpose of the study is to evaluate the combination of these strategies that maximizes 6-month weight loss in the context of a standalone digital health intervention for adults with overweight or obesity.

The investigators will recruit 176 total participants to the trial. Recruitment will occur through remote channels. Interested individuals will be directed to an online screening questionnaire; those who are eligible will then be invited to attend an initial remote session with study personnel to ensure interest and eligibility in the study. The weight loss intervention will last 6 months, and all participants will receive a "core" treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely. Depending on which group participants are assigned to in the study, some individuals will be asked to track their dietary intake, their steps, and/or their body weight via digital tools. All study tasks will occur remotely, thus, participants never need to come in-person for any intervention or assessment tasks.

The investigators will use the Multiphase Optimization Strategy (MOST) framework to identify the most effective combination of self-monitoring strategies. The factorial design will allow the research team to determine the unique and combined impact of each self-monitoring component on weight change. The primary outcome is weight change from baseline to 6 months. The research team will also assess self-monitoring engagement over 6 months and its association with weight change. To complement the main trial, the research team will also randomize half of participants to receive an interactive orientation video, in order to assess its impact on trial retention at 6 months. Overall, the information gathered from this trial will enable the construction of an optimized digital health intervention for weight loss that can be delivered remotely, which, if found to be effective, could have high potential for scalability.

Study Overview

• Status: Completed
• Conditions: Obesity; Overweight; Weight Loss; Health Behavior
• Intervention / Treatment: Behavioral: Core behavioral weight loss intervention; Behavioral: Self-monitoring weight; Behavioral: Self-monitoring steps; Behavioral: Self-monitoring diet

• Study Type: Interventional
• Enrollment (Actual): 176
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Stanford, California, United States, 94305
      • Stanford University School of Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• adults (ages 18+ years)
• body mass index (BMI) 25.0 to 45.0 kg/m^2
• smartphone ownership
• willingness to install a mobile app on their phone
• access to a personal email account
• English language proficiency
• interest in losing weight through behavioral strategies

Exclusion Criteria:

• concurrent enrollment in another weight management intervention
• loss of ≥10 lbs. in the past 6 months
• current use of a weight loss medication
• prior or planned bariatric surgery
• current or planned pregnancy in the trial period
• currently breastfeeding
• lives with someone else participating in the study
• hospitalization for a mental health condition in the past 12 months
• inability to engage in moderate forms of physical activity akin to brisk walking (assessed by the Physical Activity Readiness Questionnaire)
• if weight loss is contraindicated or might be impacted by a condition or medication (e.g., end stage renal disease, cancer, schizophrenia, dementia, steroids, anti-psychotics)
• if an individual would be better suited for a more intensive or different type of intervention based on a health condition (e.g., individuals with history of an eating disorder or cardiovascular event, uncontrolled hypertension, or uncontrolled diabetes mellitus)
• investigator discretion for safety reasons

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: None (Open Label)

Number of Arms

8

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Condition 1; Core Only	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.
Experimental: Condition 2; Core + Track Weight	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring weight; Participants randomized to receive this component will be instructed to self-monitor their body weight daily via a wireless e-scale (e.g., the Fitbit Aria Scale).
Experimental: Condition 3; Core + Track Steps	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring steps; Participants randomized to receive this component will be instructed to self-monitor their step count daily via a wrist-worn Fitbit activity monitor. A daily step goal will be given that will adapt based on progress.
Experimental: Condition 4; Core + Track Diet	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring diet; Participants randomized to receive this component will be instructed to self-monitor their dietary intake daily via the Fitbit mobile app. Participants will receive a daily calorie goal.
Experimental: Condition 5; Core + Track Weight + Track Steps	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring weight; Participants randomized to receive this component will be instructed to self-monitor their body weight daily via a wireless e-scale (e.g., the Fitbit Aria Scale).; Behavioral: Self-monitoring steps; Participants randomized to receive this component will be instructed to self-monitor their step count daily via a wrist-worn Fitbit activity monitor. A daily step goal will be given that will adapt based on progress.
Experimental: Condition 6; Core + Track Weight + Track Diet	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring weight; Participants randomized to receive this component will be instructed to self-monitor their body weight daily via a wireless e-scale (e.g., the Fitbit Aria Scale).; Behavioral: Self-monitoring diet; Participants randomized to receive this component will be instructed to self-monitor their dietary intake daily via the Fitbit mobile app. Participants will receive a daily calorie goal.
Experimental: Condition 7; Core + Track Steps + Track Diet	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring steps; Participants randomized to receive this component will be instructed to self-monitor their step count daily via a wrist-worn Fitbit activity monitor. A daily step goal will be given that will adapt based on progress.; Behavioral: Self-monitoring diet; Participants randomized to receive this component will be instructed to self-monitor their dietary intake daily via the Fitbit mobile app. Participants will receive a daily calorie goal.
Experimental: Condition 8; Core + Track Weight + Track Steps + Track Diet	Behavioral: Core behavioral weight loss intervention; All participants will receive a 6-month "core" behavioral obesity treatment consisting of goal setting, behavioral lessons, action plans, and tailored feedback - all of which will be delivered remotely.; Behavioral: Self-monitoring weight; Participants randomized to receive this component will be instructed to self-monitor their body weight daily via a wireless e-scale (e.g., the Fitbit Aria Scale).; Behavioral: Self-monitoring steps; Participants randomized to receive this component will be instructed to self-monitor their step count daily via a wrist-worn Fitbit activity monitor. A daily step goal will be given that will adapt based on progress.; Behavioral: Self-monitoring diet; Participants randomized to receive this component will be instructed to self-monitor their dietary intake daily via the Fitbit mobile app. Participants will receive a daily calorie goal.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body weight change from baseline to 6 months	change in weight from baseline to 6-month followup (in kg); assessed objectively via e-scale	baseline, 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinically significant weight loss	proportion of participants achieving ≥5% weight loss from baseline	6 months
Physical activity change from baseline to 6 months	change in physical activity from baseline to 6-month followup; assessed using Godin Leisure-Time Exercise Questionnaire	baseline, 6 months
Body weight from baseline to 1 month	change in weight from baseline to 1-month followup (in kg); assessed objectively via e-scale	baseline, 1 month
Body weight from baseline to 3 months	change in weight from baseline to 3-month followup (in kg); assessed objectively via e-scale	baseline, 3 month
BMI change from baseline to 6 months	change in BMI from baseline to 6-month followup (in kg/m^2); computed from self-reported height and e-scale weight	baseline, 6 months
Caloric intake change from baseline to 6 months	change in caloric intake from baseline to 6-month followup (in kcal); assessed using Automated 24-Hour (ASA-24) Dietary Assessment Tool (2 separate 24hr diet recalls at each time point: 1 week day, 1 weekend day)	baseline, 6 months
Engagement in self-monitoring dietary intake	average percent of days in the 6-month intervention of self-monitoring dietary intake; assessed objectively via digital health tools (mobile app)	6 months of the intervention
Engagement in self-monitoring weight	average percent of days in the 6-month intervention of self-monitoring weight; assessed objectively via digital health tools (e-scale)	6 months of the intervention
Engagement in self-monitoring steps	average percent of days in the 6-month intervention of self-monitoring steps; assessed objectively via digital health tools (activity monitor)	6 months of the intervention

Collaborators and Investigators

• Sponsor: Stanford University
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Principal Investigator: Michele L Patel, PhD, Stanford University

Study record dates

Study Major Dates

• Study Start (Actual): September 22, 2023
• Primary Completion (Actual): June 15, 2025
• Study Completion (Actual): June 23, 2025

Study Registration Dates

• First Submitted: February 10, 2022
• First Submitted That Met QC Criteria: February 10, 2022
• First Posted (Actual): February 21, 2022

Study Record Updates

• Last Update Posted (Estimated): July 1, 2025
• Last Update Submitted That Met QC Criteria: June 28, 2025
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: physical activity; mobile health; obesity treatment; intervention; weight loss; digital health; self-monitoring; behavioral treatment; dietary change; factorial design; Multiphase Optimization Strategy (MOST)
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight Changes; Overweight; Weight Loss; Body Weight
• Other Study ID Numbers: 64716; K23DK129805 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Once the study data have undergone final data cleaning, analysis, and planned publications, the investigators will make the final data collected as part of the proposed research available in electronic form to researchers who request them. Researchers will be asked to submit a data request in writing to the Principal Investigator so that the requested data can be made available while protecting the confidentiality of study participants and ensuring that the proposed research questions do not overlap with planned publication development by the project research team or other groups. The requested dataset will be free of identifiers that would permit linkages to individual research participants. The requestor must agree to maintain the privacy and confidentiality of the data and must indicate how they plan to store the data to demonstrate compliance with secure computing. All publications that emerge from this award will be publicly available via PubMed Central.

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