Optimization of Dietary Adherence in a Mobile Weight Loss Intervention

Optimizing Dietary Adherence in a Mobile Behavioral Weight Loss Intervention for Adults

The goal of this study is to test multiple individual treatment components added to a 6-month standard mobile behavioral weight loss program that are intended to help participants follow dietary recommendations and meet their dietary goals more often. The four components to be studied include switching dietary tracking methods, receiving access to a goal planning tool, receiving additional personalized text messages, and receiving three sessions with a health coach. The study will identify the best combination of these additional treatments for improving total number of weeks in the program that participants meet their dietary goals.

Study Overview

• Status: Not yet recruiting
• Conditions: Overweight and/or Obesity
• Intervention / Treatment: Behavioral: Core; Behavioral: Switch to Simplified Diet Monitoring; Behavioral: Goal Autonomy/Planning; Behavioral: Just-in-time (JIT) Messaging; Behavioral: Coach Sessions

Detailed Description

SHIFT uses a highly efficient experimental design as part of the Multiphase Optimization Strategy (MOST) to optimize a 6-month behavioral weight loss intervention for improved dietary adherence among adults with overweight and obesity with initial nonresponse to the intervention. Investigators will test four unique treatment components added to a core mobile behavioral weight loss program.

All participants will receive the Core 6-month behavioral weight loss program, which is a comprehensive intervention that includes evidence-based behavior change strategies to promote self-monitoring and adherence to personalized dietary and activity goals. The program includes an individual kick-off session, native smartphone application, text messages, daily goals, self-monitoring of diet, weight, and physical activity, weekly lessons, tailored weekly feedback, and will start with 5-6 text messages per week. The intervention targets both dietary and physical activity changes, with a greater emphasis placed on improved dietary behaviors as the primary strategy for weight loss. Participants with lower than expected adherence to their dietary goals early in the program (weeks 3-8; "nonresponders") will be randomly assigned in a 2x2x2x2 factorial trial to the On or Off level of each of these 4 additional treatments added onto the core program: 1) switching dietary self-monitoring approach (Simplified Diet), 2) adding an autonomous goals and planning tool (Goal Autonomy + Planning), 3) adding just-in-time text messaging (JIT Messaging) 4) receiving 3 telehealth sessions with a health coach (Coach). Thus, each of these participants will receive 0-4 additional treatment components for the remainder of the 6-month program. Participants with recommended levels of dietary adherence in the first 8 weeks ("responders") remain in the Core program and are not randomized in the factorial trial.

All participants (those in the factorial trial and the responders who remain in the Core only) will complete assessments at baseline, 4 weeks (brief/online only), 8 weeks (brief/online only), 3 months, and 6 months. Primary and secondary research aims are limited to participants who are randomized into the factorial trial (estimated to be approximately 65% of the total sample). The primary aim is to determine the combination of additional intervention components that maximize dietary adherence from time of randomization to 6 months among participants with low early dietary adherence. A secondary outcome is percent of participants reaching 5% weight loss from baseline to 6 months.

Decision analysis for intervention value efficiency (DAIVE) will be the decision-making approach used to select the treatment components included in the final, optimized intervention. DAIVE uses a Bayesian factorial analysis of variance that maximizes the expected value of the outcome by evaluating the predicted value associated with all possible combinations of the components. DAIVE will be used maximize the expected value of both mean total weeks of dietary adherence from randomization to 6 months and proportion reaching 5% weight loss at 6 months.

• Study Type: Interventional
• Enrollment (Estimated): 580
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Brooke T Nezami, PhD; Phone Number: 2 919-966-5852; Email: bnezami@unc.edu
• Study Contact Backup: Name: Karen E Hatley, MPH; Phone Number: 2 919-966-5852; Email: keericks@email.unc.edu

Study Locations

• United States
  • North Carolina
    • Chapel Hill, North Carolina, United States, 27514
      • University of North Carolina At Chapel Hill
      • Principal Investigator: Brooke T Nezami, PhD
      • Contact: Karen E Hatley, MPH; Phone Number: 2 919-966-5852; Email: keericks@email.unc.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• BMI 25-50 kg/m2 at baseline
• Own a smartphone with an active data and text messaging plan
• English-speaking and writing
• Willing to be randomized to any of the additional treatment components

Exclusion Criteria:

• Lost 5% or more of body weight (and kept it off) in the last 3 months
• Past diagnosis of or receiving treatment for a clinically diagnosed eating disorder (anorexia nervosa or bulimia nervosa)
• Current symptoms of alcohol or substance dependence
• Currently pregnant, pregnant within the past 6 months, currently breastfeeding, or planning to become pregnant within the next 6 months
• Untreated thyroid disease or any changes (type or dose) in thyroid medication in the last 6 months
• Hospitalization for depression or other psychiatric disorders within the past 12 months
• History of psychotic disorder or bipolar disorder
• Currently participating in a weight loss, nutrition, or physical activity study or program or other study that would interfere with this study
• Currently using prescription medications with known effects on appetite or weight (e.g., oral steroids, weight loss medications), except individuals on a stable dose of SSRIs for 3 months
• Current use of bone acting medications (e.g., raloxifene, calcitonin, parathyroid hormone during the past year, PTH-analogues [e.g., teriparatide, abaloparatide], sclerostin inhibitors (romosozumbab), RANK ligand inhibitors (denosumab) or bisphosphonates during the last two years
• Report a heart condition, chest pain during periods of activity or rest, or loss of consciousness on the Physical Activity Readiness Questionnaire (PAR-Q; items 1-4)
• Report a health condition for which the program's dietary and physical activity recommendations would be unsafe, including hospitalization for heart failure, myocardial infarction or stroke in the past year, chronic kidney disease stage IV or V, liver failure or cirrhosis, chronic obstructive pulmonary disease on oxygen or requiring steroids, osteoporosis on medication, sarcopenia, history of fragility fractures, or dementia
• Other health problems that may influence the ability to walk for physical activity or be associated with unintentional weight change, including current cancer diagnosis, cancer treatment within the past 5 years or tuberculosis
• Previous surgical procedure for weight loss or planned weight loss surgery in the next year
• Another member of the household is a participant or staff member on this trial
• Ability to provide consent (4 items adapted from the UBACC [University of California, San Diego Brief Assessment of Capacity to Consent])
• Reason to suspect that the participant would not adhere to the study intervention
• Does not live in the United States
• Cannot have participated in a research study conducted by UNC Weight Research Program in the past 2 years

Individuals endorsing joint problems, current treatment for hypertension or hyperlipidemia, or osteoporosis diagnosis not on medication will be required to obtain written physician consent to participate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: Double

Number of Arms

17

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Condition 1; Core + Switch to Simplified Diet Monitoring + Goal Autonomy/Planning + Just-in-time (JIT) Messaging + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 2; Core + Switch to Simplified Diet Monitoring + Goal Autonomy/Planning + Just-in-time (JIT) Messaging	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.
Experimental: Condition 3; Core + Switch to Simplified Diet Monitoring + Goal Autonomy/Planning + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 4; Core + Switch to Simplified Diet Monitoring + Goal Autonomy/Planning	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.
Experimental: Condition 5; Core + Switch to Simplified Diet Monitoring + Just-in-time (JIT) Messaging + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 6; Core + Switch to Simplified Diet Monitoring + Just-in-time (JIT) Messaging	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.
Experimental: Condition 7; Core + Switch to Simplified Diet Monitoring + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 8; Core + Switch to Simplified Diet Monitoring	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Switch to Simplified Diet Monitoring; Switch from standard detailed calorie tracking to a simplified diet self-monitoring approach in which participants track red foods using a color-coded traffic light system.
Experimental: Condition 9; Core with Standard Diet Monitoring + Goal Autonomy/Planning + Just-in-time (JIT) Messaging + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 10; Core with Standard Diet Monitoring + Goal Autonomy/Planning + Just-in-time (JIT) Messaging	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.
Experimental: Condition 11; Core with Standard Diet Monitoring + Goal Autonomy/Planning + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 12; Core with Standard Diet Monitoring + Goal Autonomy/Planning	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Goal Autonomy/Planning; A weekly goal planning tool that allows participants to adjust their dietary goals and make a specific plan for the week.
Experimental: Condition 13; Core with Standard Diet Monitoring + Just-in-time (JIT) Messaging + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 14; Core with Standard Diet Monitoring + Just-in-time (JIT) Messaging	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Just-in-time (JIT) Messaging; Increased frequency of text messages (1-2 per day), highly personalized based on past and current dietary adherence and weight change.
Experimental: Condition 15; Core with Standard Diet Monitoring + Coach Sessions	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.; Behavioral: Coach Sessions; Receive 3 brief telephone or video coach sessions (20-30 minutes) every other week following randomization.
Experimental: Condition 16; Core with Standard Diet Monitoring	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.
Other: Core Only (Responders); Core program (participants who are not randomized in the factorial intervention)	Behavioral: Core; Behavioral weight loss core includes daily self-monitoring (tracking) of dietary intake, physical activity, and weight; personalized daily goals for dietary intake and physical activity; weekly behavioral lessons in the study app; weekly tailored feedback on goal progress and weight change; 5-6 text messages per week.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total weeks of dietary goal adherence	Objective self-monitoring of dietary intake (pulled via the Fitbit API for those in the conditions with standard dietary self-monitoring and the Traffic Light Log app API for the those in conditions that switch to simplified dietary self-monitoring) will be used to calculate, among nonresponders randomized into the factorial trial, number of days after randomization in which the dietary goal (calorie goal or red food goal) was met ≥ 3 days/week (the daily dietary goal is defined as a complete day of tracking and ≤ the calorie/red food goal).	Time of randomization to 6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percent of participants reaching >= 5% weight loss	Scale weights at baseline and 6 months will be used to calculate, among nonresponders randomized into the factorial trial, percent weight change ( [(weight at 6 months - baseline weight) / baseline weight] × 100) and classify participants as achieving or not achieving at least 5% weight loss.	Baseline to 6 months
Total days of dietary goal adherence	Objective self-monitoring of dietary intake (pulled via the Fitbit API for those in the conditions with standard dietary self-monitoring and the Traffic Light Log app API for the those in conditions that switch to simplified dietary self-monitoring) will be used to calculate, among nonresponders randomized into the factorial trial, number of days after randomization in which the dietary goal (calorie goal or red food goal) was met (the daily dietary goal is defined as a complete day of tracking and ≤ the calorie/red food goal).	Time of randomization to 6 months
Weight Change (kg)	Estimated mean weight change in kg from baseline to 6 months among nonresponders randomized into the factorial trial. More negative values of weight change indicate greater weight loss. Weights will be objectively measured in light clothes, without shoes, on the digital smart scales in participants' homes.	Baseline, 6 months
Dietary intake	Diet will be assessed using the self-administered National Cancer Institute's Automated Self-Administered 24-hour (ASA24) Dietary Assessment Tool, a free, web-based tool for 24-hour recalls. Participants will complete unscheduled recalls on a weekday and a weekend day at each timepoint. Change in average total kcals/day will be calculated among nonresponders randomized into the factorial trial. Changes are calculated as (average daily kcal at 3/6 months - average daily kcal at baseline).	Baseline, 3 months, 6 months

Collaborators and Investigators

• Sponsor: UNC Lineberger Comprehensive Cancer Center
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2027
• Primary Completion (Estimated): September 1, 2029
• Study Completion (Estimated): October 1, 2029

Study Registration Dates

• First Submitted: May 6, 2026
• First Submitted That Met QC Criteria: May 6, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 15, 2026
• Last Update Submitted That Met QC Criteria: May 13, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: behavioral intervention; weight loss; mHealth intervention; dietary recommendations
• Additional Relevant MeSH Terms: Body Weight; Body Weight Changes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Weight Loss
• Other Study ID Numbers: 25-1211; R01HL178992 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified individual data that supports the primary outcome results will be made available through the UNC Dataverse (https://dataverse.unc.edu/).
• IPD Sharing Access Criteria: The shared data will have a persistent unique identifier (DOI) from the UNC Dataverse repository. The data will also be discoverable online through a standard web search of the study-level metadata as well as the persistent pointer from the DOI to the dataset.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No