Goal Setting in a Standalone, Digital Weight Loss Intervention: a Pilot Factorial Trial
Phase: NA
Conditions: Obesity, Overweight, Weight Loss, Health Behavior
Sponsor: Stanford University

 
Study Protocol for the Ignite Pilot Study 
Goal-setting in a standalone, digital weight loss intervention: a pilot factorial trial 
IRB eProtocol Number: 68892 
NCT Number: NCT05715242 
Principal Investigator: Patel, Michele L. (michele.patel@stanford.edu) 
Sponsor: Stanford University 
NIH Grant Number: P30DK116074 (NIDDK) 
Funded by: Stanford Diabetes Research Center Pilot & Feasibility Grants Program 
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK); 
1-800-860-8747 https://www.niddk.nih.gov/about-niddk/contact-us  
 
Role of study funders: The study funder had no role in the study design, collection, 
management, analysis, and interpretation of data; writing of the report; and the decision 
to submit the report for publication. The content is solely the responsibility of the 
authors and does not necessarily represent the official views of the NIH.  
 
Recruitment Dates: 12-05-2023 to 01-23-2024 
Data Collection Ended: 04-14-2024 
 
 
 
 
 
 
 
Last Updated: 04-09-2025
 
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TABLE OF CONTENTS: 
1. Synopsis​
4 
2. Purpose, Background and Rationale​
5 
2.1 Objective​
5 
2.2 Aim​
5 
2.3 Background and Significance​
5 
2.3.1 Obesity​
5 
2.3.2 Fully digital weight loss interventions​
6 
2.3.3 Goal setting​
6 
2.4  Theoretical Framework​
7 
2.5 Using the Multiphase Optimization Strategy (MOST)​
7 
2.6 Advancing Knowledge in the Field​
8 
3. Research Plan and Design​
8 
3.1 Overview​
9 
3.2 Study Design​
9 
3.3 Study Population​
10 
3.3.1 Recruitment​
10 
3.3.2 Retention​
11 
3.3.3 Participant Eligibility Criteria​
11 
3.3.4 Screening and randomization​
12 
3.3.5 Screen Failures​
13 
3.3.6 Withdrawal/Termination Criteria​
13 
3.4 Core Intervention​
14 
3.5 Experimental Intervention Components​
16 
3.6 Outcomes​
18 
3.6.1  Overview of Measures​
18 
3.6.2  Table of Benchmarks​
19 
3.7 Data Collection​
20 
3.7.1 Randomization and Masking​
20 
3.7.2  Quality Assurance​
21 
3.7.3 Research Ethics Approval​
21 
3.7.4 Protocol Amendments​
21 
3.7.5 Declaration of Interests​
22 
3.8 Sample Size and Statistical Power​
22 
3.9  Statistical Analysis​
22 
3.10 Data Management​
23 
3.11 Endpoint​
23 
4. Risks and Protection Against Risks​
23 
4.1 Potential Risks​
23 
4.2 Safeguards to Minimize Risks​
24 
4.2.1 Participant Population and Screening​
24 
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4.2.2 Study Team​
25 
4.2.3 Adverse Events​
25 
4.2.4 Study Procedures​
26 
4.2.5 Data Quality​
27 
4.3 Privacy​
27 
5 Dissemination​
28 
5.1 Data Sharing Plan​
28 
5.2 Access to Data​
29 
 
 
 
 
 
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1. Synopsis 
 
Title: 
Goal-setting in a standalone, digital weight loss intervention: a 
pilot factorial trial 
Grant Number: 
P30DK116074 
Study Description: 
This pilot optimization trial examines the impact of easier versus 
harder goals across 4 goal domains--calories, steps, eating 
window, Red Zone Foods--in a 10-week digital weight loss 
intervention for adults with overweight or obesity. 
Objectives: 
 
The purpose of the study is to evaluate the feasibility and 
acceptability of these goals. 
Endpoints: 
The behavioral intervention is 10 weeks  in length and will not 
be terminated early based on efficacy. The study is expected to 
end after our target sample size is reached and the final 
participant has completed the intervention. 
Study Population: 
The study population will consist of adults ( ages 18+) with body 
mass index (BMI) 25.0 to 45.0 kg/m2 from a national sample of 
the general population.  
Phase or Stage: 
Multiphase Optimization Strategy: Preparation Phase 
Description of 
Sites/Facilities 
Enrolling 
Participants: 
All study procedures, including recruitment, intervention 
delivery, and assessment, will take place remotely.  
Description of Study 
Intervention/ 
Experimental 
Manipulation: 
All participants (N=32) receive a 10-week behavioral weight loss 
intervention that includes the following empirically-supported 
components: a weight loss goal of 5%, which is consistent with 
obesity treatment guidelines; daily self-monitoring of body 
weight, calories, steps, and eating window; daily to weekly 
self-monitoring of Red Zone Foods; weekly tailored feedback via 
email; and weekly behavioral lessons and action plans via email. 
Participants are randomized to 1 of 16 conditions that vary in 
receipt of easier  versus harder goals across 4 different goal 
domains: calorie goal, step goal, eating window goal, and Red 
Zone Foods goal.  
Study Duration: 
The intervention will last 10 weeks.  
Participant Duration: 
Individual participants will complete study related tasks within 3 
months after randomization. 
 
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2. Purpose, Background and Rationale 
 2.1 Objective 
The overall goal is to examine the feasibility and acceptability of easier versus harder 
goals.  If feasibility and acceptability are established, efficacy can be evaluated in a 
subsequent, fully-powered optimization trial. The overarching research question of this 
line of work is to determine the optimal goal setting intensities that maximize weight 
loss in a digital intervention for adults with overweight or obesity.​
 
2.2 Aim 
Aim 1. To evaluate the feasibility of the four types of goals and the other intervention 
components. 
Aim 2. To determine the acceptability of the four types of goals and the other 
intervention components. 
2.3 Background and Significance 
2.3.1 Obesity 
Obesity is a significant public health problem. Obesity has become a pervasive health 
concern in the United States, with rates of 42% among adults and another 30+% 
overweight. Excess weight heightens risk for chronic diseases, including type 2 diabetes, 
and can magnify psychological distress as a result of weight stigma. Behavioral weight 
loss interventions that involve frequent in-person meetings, diet and exercise goals, and 
behavioral strategies are the gold standard for treating overweight and obesity. These 
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traditional treatments are effective in producing weight loss up to 10%, but often lack 
scalability. This research is significant because it will optimize a behavioral weight loss 
intervention that has potential for broad reach and scalability. 
2.3.2 Fully digital weight loss interventions 
Digital health interventions that deliver treatment remotely seek to minimize burden 
and decrease costs compared to in-person interventions. With widespread penetration 
of smartphones among U.S. adults, digital health interventions have potential to reach 
booad geographic segments of the population. Compared to traditional interventions 
with counseling, standalone digital interventions offer greater scalability given lower 
personnel costs, and produce modest weight loss. However, weight loss tends to be 
modest; thus, more work is needed to enhance the efficacy of fully digital approaches. 
2.3.3 Goal setting 
Goal setting is a core component of behavioral obesity treatment. Goals can focus on 
behaviors (e.g., to exercise more) or outcomes (e.g., to lose weight). Many behavioral 
obesity treatments include goals for weight loss, physical activity, and calories, yet there 
is large variability in the specific intensities of these goals. Past research has shown that 
personalized goals are helpful at promoting behavior change, adaptive goals help more 
than static goals,  immediate goals help more than gradual goals, and larger goals help 
more than smaller goals, However, to our knowledge, no study has examined the 
optimal goal intensity (i.e., harder versus easier goals) to be given in a fully digital 
weight loss intervention. Doing so would aid in identifying the most efficacious and least 
burdensome approach to goal setting in a highly scalable context. ​
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2.4  Theoretical Framework 
Self-regulation theories, including Social Cognitive Theory and Control Theory, posit 
that behavior change occurs through comparison of one’s behavior to one’s goals or past 
performance. Meta-analyses have demonstrated that goal setting, self-monitoring, and 
feedback work in tandem to promote greater behavior change and weight loss.  
 2.5 Using the Multiphase Optimization Strategy (MOST)  
The Multiphase Optimization Strategy (MOST) is an engineering-inspired framework 
used for systematically constructing multicomponent behavioral interventions. MOST 
involves three phases: Preparation, Optimization, and Evaluation. In the Preparation 
phase, components and their respective levels of interest are identified and pilot tested. 
A conceptual model is created to depict how behavior change occurs through the various 
components and mechanisms. In the Optimization phase, the unique and combined 
effects of those components are evaluated in a fully-powered trial. Often, a factorial 
design is used. Components and component-levels that produce a minimal clinically 
important difference are retained in the newly optimized intervention, whereas those 
that produce minimal or iatrogenic effects are removed. Lastly, in the Evaluation phase, 
the newly optimized intervention is tested against a meaningful comparator to 
determine efficacy of the intervention package. The goal is to achieve intervention 
EASE, by balancing the Effectiveness of the intervention against other constraints such 
as Affordability, Scalability, and Efficiency.   
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2.6 Advancing Knowledge in the Field 
No study, to our knowledge, has examined the optimal goal setting intensity in a fully 
digital weight loss intervention. Examining both the unique and combined effects of 
different goal intensities will enable creation of an intervention that maximizes weight 
loss while minimizing undue patient burden and effort.   
3. Research Plan and Design​ 
The study aim is to conduct a 10-week pilot optimization trial (N=32) using a factorial 
design to evaluate goal setting intensities (easier vs. harder) across 4 goal domains: 
calorie goal, step goal, eating window goal, and Red Zone Food goal in a fully digital 
weight loss intervention for adults with overweight/obesity. As shown in the conceptual 
model (Figure), participants will receive either an easier or harder version of 4 goals, 
and we will examine their effect on perceived helpfulness, perceived ease, goal 
attainment, self-monitoring engagement, and subsequently, diet and physical activity, 
and weight loss.  
 
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3.1 Overview 
All participants will receive a core intervention and either an easier or harder version of 
4 goal domains: calorie goal, step goal, eating window goal, and Red Zone Food goal. 
The intervention will last 10 weeks, with remote assessments at baseline, 4 weeks, and 
10 weeks. All procedures, including the intervention and assessment, will occur 
remotely. 
3.2 Study Design 
 This optimization trial will use a 24 full factorial design (i.e., 2x2x2x4) to test easier vs. 
harder versions of 4 goals. As shown in the Table, for each goal domain, half of 
participants will be randomly assigned to receive the easier version while the other half 
will receive the harder version. In total, participants will be randomized to 1 of 16 
experimental conditions. A factorial trial compares means across combinations of 
conditions in order to test main effects of components and their interactions. For 
example, the main effect of calorie goal intensity is the mean for the participants who 
receive the easier version of it (i.e., experimental conditions 1-8) versus the mean of 
those who receive the harder version of it (i.e., conditions 9-16). 
 
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3.3 Study Population 
3.3.1 Recruitment 
Participants will be recruited through several remote channels nationwide and in the 
San Francisco Bay Area: a) social media posts (Twitter and Facebook), b) research 
registries (ResearchMatch.org, a national registry of health research volunteers; 
ClinicalTrials.gov registry; the Stanford Diabetes Research Center’s registry comprised 
of adults with pre-diabetes or type 2 diabetes, as well as healthy individuals); c) 
community advertisements (Nextdoor, Craigslist), and/or d) university-affiliated 
research websites. The target recruitment is 32 participants. Briefly, eligibility criteria 
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include: adults ≥18 years, body mass index (BMI) 25-45 kg/m2, smartphone ownership, 
no recent weight loss ≥10 lbs., and no condition that contraindicates weight loss. 
3.3.2 Retention  
Retention will be maximized by reimbursing participants for their time spent on the 
4-week  and 1-week reassessments ($30, $30, respectively) and by providing an 
additional $20 for completion of dietary recall measures. Study staff will ask permission 
to collect multiple phone numbers, email addresses, and family or close friend contact 
information, and assess preferences for contact methods. Reminder text 
messages/emails will be sent prior to the remote evaluation visits and follow up with 
participants via various channels (text, phone, email) if they have yet to complete 
assessments.  
3.3.3 Participant Eligibility Criteria 
Inclusion 
Criteria 
●​ adults (ages 18+ years) 
●​ body mass index (BMI) 25.0 to 45.0 kg/m2 
●​ smartphone ownership 
●​ willingness to install the Fitbit mobile app on their phone 
●​ access to a personal email account 
●​ English language proficiency 
●​ interest in losing weight through behavioral strategies 
●​ Living in the United States 
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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  
●​ 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 
 
3.3.4 Screening and randomization 
Recruitment materials will direct interested individuals to an online screening 
questionnaire (REDCap) that describes the study and assesses initial eligibility. Eligible 
candidates will then receive an email invitation to sign up for an initial remote visit and 
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complete an interactive orientation video. At this visit, trained study staff will confirm 
eligibility and describe study procedures. If individuals are interested in participating, 
study staff will obtain informed consent to assure that they fully understand the 
demands and nature of the study before enrolling. Next, study staff will help 
participants create a Fitbit account, and administer online baseline measures. Once 
completed, participants will be randomized to 1 of 16 experimental conditions via an 
algorithm on REDCap. Study staff will mail all participants an e-scale to obtain weight 
measurement along with a Fitbit activity monitor. Staff will email instructions for 
setting up the Fitbit app and syncing the e-scale and activity monitor devices, and 
provide the assigned intervention and corresponding program materials. Staff will 
troubleshoot, as needed. 
3.3.5 Screen Failures 
Participants who consent but then become ineligible prior to randomization will be 
asked to withdraw from the study and will not be randomized. Examples would include 
if a participant’s baseline weight collected via the study-issued scale (after consenting) 
puts them out of range on the BMI criterion (i.e.,  no longer being in the 25.0-45.0 
kg/m2 range), or if a participant reports a pregnancy or exclusionary medical condition 
in the period between consent and randomization. All other reports of changes to 
eligibility criteria will be decided upon by study investigators prior to randomization. 
3.3.6 Withdrawal/Termination Criteria 
If after randomization and during the study period the participant no longer meets 
certain eligibility criteria, they will be asked to withdraw from the study. This includes 
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the following: if a participant becomes pregnant during the study;  finding out that 
certain criteria were falsified or not reported (e.g., initial age, initial BMI, concurrent 
enrollment in another weight management intervention, a health condition that 
contraindicates weight loss or requires more intensive treatment), or  investigator 
discretion for safety reasons. 
Participants who become pregnant during the study period will be asked to leave the 
study. Changes in health behaviors and weight may not be healthy for a baby during 
pregnancy. Note that if a participant begins use of an antiobesity medication during the 
study, they will not be asked to withdraw from the study. 
3.4 Core Intervention 
All participants will receive a core intervention consisting of the following empirically- 
and theoretically- supported components shown to promote self-monitoring 
engagement: 
Fitbit mobile app: 
We will leverage an existing state-of-the-art app from Fitbit that is freely available on 
iPhone and Android platforms. At baseline, participants will install the mobile app. 
Weight loss goal: 
All participants will receive a goal to achieve 5% weight loss by 10 weeks, which is 
consistent with obesity treatment guidelines and equates to 0.5-2 lbs weight loss/week.  
Self-monitoring diet: 
Participants will be instructed to self-monitor their dietary intake daily via the Fitbit 
mobile app. This app allows users to track all foods and beverages consumed using a 
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built-in nutritional database, barcode scanner, or manual entry of individual recipes, 
and to view graphically their change in caloric intake.  
Self-monitoring steps: 
Participants will be instructed to self-monitor their step count daily via a wrist-worn 
Fitbit activity monitor (Fibit Inspire 3). The Fitbit activity monitor will be synced with 
the Fitbit app to allow participants to view their progress towards the step goal. 
Self-monitoring weight: 
Participants will be instructed to self-monitor their body weight daily via a wireless 
e-scale (the Fitbit Aria Scale). The e-scale will be synced with the Fitbit mobile app, 
providing real-time graphical feedback. 
Self-monitoring eating window: 
Participants will be instructed to self-monitor their prior day’s eating window (start and 
stop times) every morning via a brief web-based survey (REDCap). They will receive 
immediate feedback as to whether they met their goal. 
Self-monitoring Red Zone Foods: 
Participants will be instructed to self-monitor their Red Zone Foods (highly caloric 
foods of limited nutritional value, such as ice cream and soda) via a brief web-based 
e-checklist (REDCap). They will receive this e-checklist daily in weeks 1 and 10 and 
weekly in weeks 2-9. They will receive immediate feedback as to whether they met their 
goal. 
Tailored feedback: 
Each week, participants will receive an email with tailored feedback pertaining to their 
progress on their assigned self-monitoring goals (described below) and other 
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intervention components. Feedback will be automatically generated using Microsoft 
Office’s Mail Merge feature. 
Behavioral skills training: 
Each week, participants will receive an email with theory-informed skills training 
materials that include structured behavioral lessons on nutrition and physical activity as 
well as corresponding action plans. These materials will be adapted from our recent 
trials as well as from gold standard weight loss curricula. Lessons include topics such as 
reading nutrition labels and promoting physical activity. Embedded in this email will be 
a link to a brief action plan survey (Qualtrics) that incorporates motivational 
interviewing and problem-solving strategies. Specifically, participants will be prompted 
each week to reflect on their current behaviors and areas for change, generate actionable 
steps to change, identify confidence in doing so, and brainstorm potential barriers and 
support people 
3.5 Experimental Intervention Components 
Participants will be randomized to 1 of 16 conditions (Table above) that vary in their 
receipt of harder vs. easier goals across 4 goal domains. A 24 full factorial design will 
allow for all combinations to be tested. 
 
Calorie goal (easier vs. harder). It is common in behavioral obesity treatment to assign a 
tailored calorie goal based on an individual’s baseline height, weight, sex, age, and 
normal activity level, with a minimum of 1200 Calories (kcal)/day for women and 1500 
kcal/day for men, based on national guidelines. In this pilot study, participants will be 
randomized to receive either an easier calorie goal (i.e., the tailored calorie goal plus 
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250 extra calories in daily budget) or a harder calorie goal (i.e., the standard calorie goal 
as is).  
Step goal (easier vs. harder). In the baseline survey, participants will complete the 
Godin Lesiure-Time Exercise Questionnaire that will provide a leisure score index to be 
used determine their baseline activity level. Scores of 0-13 (interpreted as “Insufficiently 
Active”) will be assigned a baseline goal of 5,000 steps per day, scores of 14-23 
(“Moderately Active”) will be assigned a baseline goal of 7,000 steps per day, and scores 
≥24 (“Active”) will be assigned a baseline goal of 10,000 steps per day. Participants will 
be randomized to receive either an easier step goal (i.e., this baseline step goal as is) or a 
harder step goal (i.e., this baseline step goal plus 1,500 steps). Beginning in week 2, this 
step goal will adapt each week based on the prior week’s progress. Participants will 
receive a daily step goal of either the 40th (if easier) or 60th (if harder) percentile of the 
prior week’s daily step count, rounded up to the nearest 500 steps. 
 
Eating window goal (easier vs. harder). Limiting eating windows is the crux of time 
restricted eating. Participants who receive the easier version of this goal will be 
instructed to eat within a 12-hour window every day, while those receiving the harder 
version will be instructed to eat within a 9-hour window every day. Participants will be 
able to self-select at baseline their preferred eating window (e.g., 9 AM to 9 PM for 
someone in the easier version, or noon to 9 PM for someone in the harder version). 
 
Red Zone Food goal (easier vs. harder). Limiting Red Zone Foods is intended to help 
lower caloric consumption, aiding in weight loss. Participants who receive the easier 
version of this goal will be instructed to eat no more than 5 Red Zone Foods every day, 
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while those receiving the harder version will be instructed to eat no more than 1 Red 
Zone Food every day. 
3.6 Outcomes 
3.6.1  Overview of Measures   
The primary outcomes of this pilot study relate to the feasibility and acceptability 
of the various goals and their intensity levels. We will compare these outcomes to 
our a priori benchmarks listed in the Table below. Additional exploratory 
outcomes are also included in this table, and marked with an asterisk. The 
planned primary outcome for the subsequent fully-powered optimization trial is 
weight change. We will collect data on weight change in our pilot study. Based on 
prior research of digital weight loss interventions, we have set benchmarks for 
the 3% and 5% thresholds, which have been associated with improved 
cardiometabolic health. We will measure body weight using smart scales (Fitbit 
Aria Air) that automatically transmit data to the research team. The smart scales 
will be mailed to participants. Participants will be provided with best practices 
prior to each weight assessment: calibrate upon arrival; weigh in the AM without 
clothing, before eating/drinking, and after voiding. We will also administer 
behavior change measures that will be used in the subsequent optimization trial. 
In particular, dietary recalls will be measured using the Automated 24-Hour 
(ASA-24) Dietary Assessment Tool and physical activity will be measured using 
the GLTEQ self-report measure as well as objectively via the Fitbit Inspire 3 
activity tracker to evaluate step count. We will also assess perceived ease of the 
goals. 
 
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3.6.2  Table of Benchmarks   
  
Feasibility and Acceptability Metric 
Benchmark to meet 
Intervention engagement over 10 weeks 
  
% days of self-monitoring body weight, steps, dietary intake 
(assessed separately) 
75% 
 
% days of self-monitoring eating window*  
75% 
 
% days of self-monitoring Red Zone Foods (when instructed to do 
so)* 
75% 
  
% action plans completed; feedback emails read; lessons reviewed 
(assessed separately)* 
80% 
Goal attainment over 10-week intervention 
 
% of days meeting the daily calorie goal 
75% 
 
% of days meeting the daily step goal 
75% 
 
% of days meeting the daily eating window goal 
75% 
 
% of days meeting the daily Red Zone Food goal (when instructed to 
track them) 
75% 
 
% of days meeting the daily protein goal* 
75% 
Recruitment, retention, and survey completion 
  
% enrolled among those eligible from the online screen* 
50% 
  
% retention at 4 weeks*, 10 weeks 
80% 
  
% survey completion at  baseline, 4 weeks*, 10 weeks 
80% 
Acceptability 
 
% of participants who would recommend the weight loss program to 
a friend who is trying to lose weight 
80% 
 
% of participants who indicated the [ ] goal was moderately, very, or 
extremely helpful (separately for all goals: calorie, steps, eating 
window, Red Zone Foods, protein, 10-week weight loss, weekly 
weight loss)* 
80% 
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% of participants who indicated that tracking [ ] was moderately, very, 
or extremely helpful (assessed separately for all self-monitoring 
domains: weight, food, steps, weight)* 
80% 
 
% of participants who indicated that receiving a personalized progress 
report, lesson, action plan (assessed separately) was moderately, 
very, or extremely helpful* 
80% 
Clinically significant weight loss 
  
≥ 3% weight loss at 10 weeks* 
At least 50% of 
participants 
  
≥ 5% weight loss at 10 weeks* 
At least 33% of 
participants 
* indicates exploratory outcome (not reported on clinicaltrials.gov) 
3.7 Data Collection 
Data will be collected at baseline, 4 weeks, and 10 weeks. All data collection procedures 
will occur through remote means. Weights will be collected via e-scale, self-monitoring 
data will be collected objectively by the digital tools, and all other measures will be 
collected via online questionnaire (REDCap or a dietary recall tool). Fitabase software 
will be used to retrieve the objective self-monitoring data via Fitbit’s API. At the time of 
each remote evaluation, participants will be emailed instructions for weighing 
themselves on their e-scales, and sent a link to the online survey to complete measures. 
Reminders will be sent if weights are not synced or surveys not completed. 
3.7.1 Randomization and Masking 
Following recommendations for factorial designs, we will randomize participants to the 
16 conditions using permuted block randomization with a block size of 16. The 
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allocation sequence will be generated by the study’s PI and stored in REDCap. Study 
staff will use REDCap to implement the random allocation sequence (i.e., randomize a 
participant) once both the baseline weight and web-based surveys are submitted. The 
first day of the weight loss intervention will occur approximately two days after 
randomization. On that day, participants will receive an automated email describing 
their treatment assignment. Participants will not masked to treatment assignment. 
Study staff will not be masked to treatment assignment due to logistical limitations and 
the need for quality assurance. However, all surveys will be sent via REDCap and 
completed without study staff involvement. In addition, study staff will not have access 
to the allocation sequence. 
3.7.2  Quality Assurance 
Participants enrolled in this study may not participate in other research studies where 
weight loss is targeted. In addition, participants will be asked to refrain from 
self-monitoring behaviors that are not assigned to them and refrain from using any 
other weight-related apps or activity trackers for the duration of the trial. By explaining 
the rationale of the study prior to enrollment and setting expectations upfront, we hope 
to keep compliance with these instructions high.  
3.7.3 Research Ethics Approval 
The Stanford Institutional Review Board has approved our study protocol. 
3.7.4 Protocol Amendments 
Protocol modifications will be communicated to all study investigators and approved by 
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the IRB prior to implementation, and the trial registry will be updated accordingly. 
3.7.5 Declaration of Interests 
The investigators report no competing interests. 
3.8 Sample Size and Statistical Power 
Aligning with recommendations for conducting pilot studies, the purpose of our 
proposed pilot study is to assess feasibility and acceptability of the intervention. As a 
result, no power analysis will be conducted. The sample size (n=32) was selected to have 
the same number of participants (n=2) per condition and allows us to meet budget and 
time restrictions.  
3.9  Statistical Analysis 
We will use descriptive data to assess feasibility and acceptability outcomes, and will 
compare them to our a priori feasibility benchmarks, outlined in the Table above. To 
evaluate exploratory changes in efficacy outcomes that will be evaluated in a larger-scale 
trial, we will descriptively assess the main effects of each goal-setting component being 
tested, along with their interactions. Unlike in an RCT that compares the means of each 
treatment arm to one another, a factorial trial compares the means across combinations 
of experimental conditions and uses the entire sample, which makes it an efficient and 
economical study design. For example, the main effect of the Calorie Goal intensity is 
calculated by computing the mean for the participants who receive the harder goal (i.e., 
those in experimental conditions 9-16 in the Table above) versus the mean of those who 
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receive the easier goal (i.e., those in experimental conditions 1-8), collapsed across the 
other factors. In a subsequent optimization trial, we will be powered to detect these 
effects. 
3.10 Data Management 
 REDCap will be used for direct data entry, randomization, and tracking participants’ 
status in the study.  ​ ​
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3.11 Endpoint 
The behavioral intervention is 10 weeks in length and will not be terminated early 
based on efficacy. The study is expected to end after we reach our target sample size 
and the final participant has completed the intervention. 
4. Risks and Protection Against Risks​
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4.1 Potential Risks   
Potential risks include: 1) breach of confidentiality; 2) psychological distress associated 
with answering questions about psychological or behavioral content (e.g., perceived 
stress level, weight bias, body weight) or engaging in the intervention; 3) medical risks 
associated with participating in a behavioral weight loss treatment. These risks are 
consistent with typical risks associated with research participation in behavioral weight 
loss studies and are expected to be minimal. There are no invasive procedures planned. 
We will monitor the occurrence of adverse events and serious adverse events as required 
for these types of intervention studies. 
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4.2 Safeguards to Minimize Risks 
4.2.1 Participant Population and Screening 
All participants will be adults with overweight/obesity who are otherwise healthy. 
Individuals who are pregnant or who have a medical condition that would limit 
participation in a behavioral weight loss intervention or be better suited for a more 
intensive or different type of intervention are excluded from our trial (e.g., individuals 
with a history of an eating disorder or cardiovascular event, uncontrolled diabetes 
mellitus or hypertension, cancer, dementia). Healthy volunteers are included to reduce 
the risk of any complications that could arise from participation in a behavioral weight 
loss intervention that is of lower intensity and remotely delivered. Risks to participants 
are anticipated to be low given that we are examining evidence-based intervention 
strategies and promoting weight loss through lifestyle change (e.g., decrease intake of 
unhealthy foods, increase steps). We will not be including a vulnerable population (e.g., 
children, pregnant women) as participants. 
To ensure participant safety in this study, a set of screening procedures that are 
common in behavioral weight loss interventions, such as ensuring participants are safe 
to engage in moderate intensity physical activity and ensuring participants do not have a 
medical condition that is contraindicated in a remote weight loss program will be 
employed. The content of the weight loss intervention – including moderate-intensity 
physical activity and dietary change through reduction of unhealthy foods and increase 
of healthy foods – is commensurate with the current national guidelines for behavioral 
obesity treatment.  
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4.2.2 Study Team  
The Principal Investigator will be responsible for regular monitoring of data All study 
procedures involving participant contact will be done by trained research personnel who 
have completed formal human subjects training (e.g., CITI Certification) to ensure 
understanding of methods and procedures to protect personal health information, and 
the importance of maintaining the confidentiality of study participants. 
4.2.3 Adverse Events 
Information will be collected on all potential types of adverse events, including 
musculo-skeletal soreness and injury, as well as major medical events including injuries 
or conditions that result in health care provider visits or hospitalization. Serious adverse 
events will be reported promptly in writing to the Stanford IRB, and all adverse events 
reported to the appropriate entities as required throughout the study. 
Participants will be provided with contact information for the study team, including a 
study phone number and study email address that will be checked daily by the study’s 
Research Assistant (RA) and/or the PI. This contact information will be provided to 
participants on multiple occasions, including in the informed consent form, in weekly 
intervention-related emails, and in the study evaluation emails sent at baseline, 4 weeks, 
and 10 weeks. In addition, participants will speak to study staff via phone/video 
conference at the beginning of the study (before randomization) to ensure eligibility, 
interest, and understanding of study procedures and assigned intervention components. 
During this call, participants will be encouraged to report any adverse events, serious 
adverse events, or discomforts that arise during the trial to the study team. 
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 The RA will be the primary source of contact with participants (e.g., sending 
intervention materials and survey measures via email). The RA will alert the PI of any 
negative participant feedback. Based on participant feedback, the PI will revise the 
intervention and study procedures as necessary to ensure that risks of injury or 
discomfort are minimized and will seek IRB approval before doing so. All study 
personnel will have access to each other’s contact information, including an email 
address and phone number, in a centralized database to facilitate easy communication. 
4.2.4 Study Procedures 
The consent forms and phone/Zoom-based conversations during the screening stage 
will include disclosures about the purpose of the study, the nature and content of study 
measures, and participants' rights to decline answering questions or discontinue 
participation at any time without ramification. 
To minimize risks related to experiencing psychological discomfort, participants will be 
informed upfront of the types of survey questions and assessment measures to expect, 
and will be made aware they can skip any questions they do not feel comfortable 
answering with no impact on their participation or compensation. Any participants, 
including those who experience discomfort as a result of completing intervention 
components, are able to discontinue participation from the study at any time. We expect 
minimal adverse psychological effects. 
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4.2.5 Data Quality 
Data quality will be assured by using standardized procedures via comprehensive 
intervention and assessment protocols. Dr. Patel will also closely monitor the data and 
will use IRB-approved documentation strategies of research procedures. Any updates to 
the protocol will first receive approval from the IRB before implementing. 
4.3 Privacy 
Confidentiality of participant data will be maintained by: 1) handling individual data by 
participant ID number, rather than by name; 2) storing all individual data in password 
protected files and electronic hard drives, and in encrypted data servers at Stanford; 3) 
not disclosing individual data to anyone other than trained study staff; 4) using the 
Stanford protected version of Qualtrics and REDCap, allowing encrypted transmission 
of all survey data; 5) presenting study findings in aggregate in publications, 
presentations, and all other dissemination efforts. 
Investigators will be sensitive to issues surrounding confidentiality and other forms of 
participant risk, including discomfort surrounding talking about personal health issues 
and behaviors.  The study team's onboarding will include a discussion of confidentiality 
and how this is to be maintained throughout the course of the study. All staff will have 
taken the required online human subjects course on this topic (e.g., CITI training). In 
addition, this topic will be regularly addressed during weekly staff meetings where staff 
will be encouraged to ask questions pertaining to this issue.  
 
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All study procedures will occur through remote means. Eligibility screening will initially 
occur via REDCap questionnaire, and confirmed by study personnel via 1:1 phone or 
Zoom conversation. Communications about the study and obtaining informed consent 
will also be conducted individually via phone or Zoom with a member of the study team. 
These communications will be conducted by a study staff member who is in a private, 
closed room. Participants will be requested to complete these sessions in a private, 
closed room when possible to protect their privacy. Only study team members will have 
access to the email account and telephone line used to communicate with participants. 
Participant data obtained during the study will be gathered by researchers who are 
HIPAA and CITI certified. Responses will be entered into a computer database that is 
password protected. Data will be stored on a remote server (not on a local hard drive) 
and will be encrypted and accessible only to select study investigators. Data will be 
coded. This study will impose minimal risk for participants. Confidentiality will be 
enhanced by assigning a unique participant ID number to each participant. Identifying 
information will be removed from these datasets; names will be replaced with 
pseudonyms prior to analysis.  
5 Dissemination 
5.1 Data Sharing Plan 
The clinical trial is registered at ClinicalTrials.gov (NCT05715242) and information 
about the results will be submitted there for public posting. Results information will be 
submitted no later than one year after the trial’s primary completion date. Consent 
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documents for this trial will include a specific statement relating to posting of clinical 
trial information at ClinicalTrials.gov. 
The Stanford University School of Medicine has an internal policy in place to ensure that 
clinical trials registration and results reporting occur in compliance with policy 
requirements. Specifically, the policy states that the PI will be the Responsible Party for 
registering, updating, and reporting results from the clinical trial in a timely manner. 
Registration was completed  via the Stanford ClinicalTrials.gov Protocol Registration 
System (PRS).  
Study results will be shared through presentations at national conferences of 
professional organizations (e.g., Society of Behavioral Medicine; The Obesity Society), 
submissions in peer-reviewed journals relevant to Dr. Patel’s research, and postings on 
social media channels. 
5.2 Access to Data 
The principal investigator will retain access to the final trial data set. 
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