Nudge-Based Exercise Intervention for Adolescents With Obesity

Development and Application of a Nudge-Based Exercise Program for Adolescents With Obesity

This study will evaluate whether a nudge-based exercise program can improve body mass index (BMI) and physical activity in adolescents with obesity. About 140 adolescents aged 10-19 years will participate. Participants will be placed into one of two groups according to the order in which they are admitted to the hospital. One group will receive a standard exercise intervention, while the other group will receive an 8-week nudge-based exercise program designed to make regular physical activity easier to start and maintain.

The nudge-based program uses simple behavioral strategies to make exercise easier to start and maintain, including framed and visual information, default exercise options, reminders, peer comparison and support, goal commitment, progress feedback, and small incentives. The program combines face-to-face sessions during hospitalization with home-based support, exercise tools, activity recording, and online follow-up.

The main outcomes are changes in BMI and physical activity. Other outcomes include body composition, blood metabolic markers, health-related quality of life, and exercise self-efficacy. Assessments will be conducted before and after the intervention, with follow-up assessments used to examine whether the effects are maintained over time.

Study Overview

• Status: Recruiting
• Conditions: Pediatric Obesity
• Intervention / Treatment: Behavioral: Standard Exercise Intervention; Behavioral: Nudge-Based Exercise Intervention

• Study Type: Interventional
• Enrollment (Estimated): 140
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Chenxin Gan; Phone Number: 18205049751; Email: gcx5101@163.com

Study Locations

• China
  • Jiangsu
    • Nanjing, Jiangsu, China
      • Recruiting
      • Nanjing Children's Hospital
      • Contact: Chenxin Gan; Phone Number: 18205049751; Email: gcx5101@163.com
      • Principal Investigator: Yubing Wang

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Aged 10-19 years.
• Body mass index (BMI) at or above the 95th percentile for age and sex according to the Chinese BMI screening criteria for overweight and obesity in children and adolescents.
• Able to communicate and understand study instructions.
• Willing to participate in the study and provide written informed consent, with informed consent from a parent or legal guardian as required.

Exclusion Criteria:

• Known secondary causes of obesity, including hypothalamic, endocrine, genetic, or syndromic obesity.
• Use of anti-obesity medications, including injectable glucagon-like peptide-1 (GLP-1) receptor agonists, within 3 months before enrollment.
• Severe cardiovascular or cerebrovascular disease, severe hepatic or renal dysfunction, or other serious organic diseases that may affect participation or study outcomes.
• Psychiatric disorders or cognitive impairment that may interfere with participation or completion of study assessments.
• Current participation in another weight-loss, structured exercise, or other intervention program that may affect body weight or physical activity.
• Any contraindication to exercise or medical or physical condition that substantially limits participation in the prescribed exercise program.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Standard Exercise Intervention; Participants in this arm receive a standardized exercise intervention based on current clinical guidance. The program focuses on moderate-intensity aerobic exercise performed 3-4 times per week for 40-50 minutes per session. Participants also receive routine exercise-related health education and follow-up support.	Behavioral: Standard Exercise Intervention; Participants receive a standardized exercise program based on current clinical guidance. The program primarily consists of moderate-intensity aerobic exercise performed 3-4 times per week for 40-50 minutes per session. Participants also receive routine exercise-related health education and regular follow-up support.
Experimental: Nudge-Based Exercise Intervention; Participants in this arm receive an 8-week nudge-based exercise intervention designed to promote the initiation and maintenance of physical activity. The intervention uses strategies including framed and visual information, social reference, default exercise options, reminders, commitment, progress feedback, and incentives. It combines structured face-to-face sessions during hospitalization with an exercise nudge package and home-based support through online reminders, activity recording, peer interaction, and incentives.	Behavioral: Nudge-Based Exercise Intervention; Participants receive an 8-week nudge-based exercise program designed to facilitate the initiation and maintenance of physical activity. The intervention incorporates framed and visual information, social reference, default exercise options, reduced effort for accessing exercise opportunities, reminders, commitment strategies, progress feedback, and incentives. During hospitalization, participants receive structured face-to-face sessions and an exercise nudge package containing exercise equipment, activity task cards, and a reminder device. After discharge, home-based support is provided through online exercise reminders, activity recording, peer interaction, progress feedback, and incentives.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Body Mass Index (BMI)	Body weight and height will be measured at baseline and approximately 3 months after baseline. Weight in kilograms and height in meters will be combined to report a single BMI value using the formula: BMI = weight (kg) / [height (m)]^2. Body weight and height are component measurements used to derive BMI for this endpoint and are not separate outcome measures. Change in BMI will be calculated as the BMI value at approximately 3 months after baseline minus the baseline BMI value. The reported unit of measure is kg/m^2.	Baseline and approximately 3 months after baseline
Change in Physical Activity	Physical activity will be assessed using the Chinese version of the International Physical Activity Questionnaire-Short Form (IPAQ-SF). The questionnaire records walking, moderate-intensity, and vigorous-intensity physical activity during the previous 7 days. The activity-specific values will be converted to metabolic equivalent of task minutes per week (MET-minutes/week) and summed according to the IPAQ-SF scoring method to generate a single total physical activity score. The individual activity categories are components of the total score and are not separate outcome measures under this endpoint. Change in physical activity from baseline to the follow-up assessment will be evaluated.	Baseline and approximately 3 months after baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Total Sedentary Time	Sedentary behavior will be assessed using a questionnaire that records time spent in common sedentary activities outside school hours on each day of a typical week, including screen-based activities, homework and reading, tutoring, motorized transportation, sedentary hobbies, social activities, and playing musical instruments. Total sedentary time will be summarized as average minutes per day. Change from baseline to follow-up will be evaluated.	Baseline and approximately 3 months after baseline
Change in Body Fat Percentage	Body fat percentage will be measured by bioelectrical impedance analysis using the InBody H30 body composition analyzer and reported as a percentage (%). Change from baseline to follow-up will be evaluated.	Baseline and approximately 3 months after baseline
Change in Skeletal Muscle Mass	Skeletal muscle mass will be measured by bioelectrical impedance analysis using the InBody H30 body composition analyzer and reported in kilograms (kg). Change from baseline to follow-up will be evaluated.	Baseline and approximately 3 months after baseline
Change in Exercise Self-Efficacy	Exercise self-efficacy will be assessed using the Exercise Self-Efficacy Scale (ESES), which evaluates participants' confidence in maintaining regular exercise when facing barriers such as fatigue, lack of time, or unfavorable weather. Higher scores indicate greater exercise self-efficacy. Change from baseline to follow-up will be evaluated.	Baseline and approximately 3 months after baseline
Change in Health-Related Quality of Life	Health-related quality of life will be assessed using the Chinese version of the Pediatric Quality of Life Inventory Generic Core Scales. The scale contains 23 items covering physical, emotional, social, and school functioning. Scores are transformed to a 0-100 scale, with higher scores indicating better health-related quality of life. Change in the total score from baseline to follow-up will be evaluated.	Baseline and approximately 3 months after baseline

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Fasting Blood Glucose	Fasting blood glucose will be assessed by laboratory testing after an overnight fast. Change will be calculated as the follow-up value minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Fasting Insulin	Fasting insulin will be assessed by laboratory testing after an overnight fast. Change will be calculated as the follow-up value minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)	Insulin resistance will be estimated using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), calculated from fasting glucose and fasting insulin concentrations. Higher values indicate greater insulin resistance. Change will be calculated as the follow-up value minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Glycated Hemoglobin (HbA1c)	Glycated hemoglobin (HbA1c) will be assessed by laboratory testing and reported as a percentage (%). Change will be calculated as the follow-up value minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Total Cholesterol Concentration	When available, total cholesterol concentration will be recorded from routine clinical laboratory testing performed during clinical re-examination and reported in millimoles per liter (mmol/L). Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Triglyceride Concentration	Triglyceride concentration will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in millimoles per liter (mmol/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Low-Density Lipoprotein Cholesterol (LDL-C) Concentration	Low-density lipoprotein cholesterol (LDL-C) concentration will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in millimoles per liter (mmol/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in High-Density Lipoprotein Cholesterol (HDL-C) Concentration	High-density lipoprotein cholesterol (HDL-C) concentration will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in millimoles per liter (mmol/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Alanine Aminotransferase (ALT) Activity	Alanine aminotransferase (ALT) activity will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in units per liter (U/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Aspartate Aminotransferase (AST) Activity	Aspartate aminotransferase (AST) activity will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in units per liter (U/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline
Change in Serum Uric Acid Concentration	Serum uric acid concentration will be recorded from routine clinical laboratory testing conducted as part of routine clinical re-examination and reported in micromoles per liter (μmol/L). No additional blood sample will be collected solely for this study. Change from baseline will be calculated as the value at approximately 3 months after baseline minus the baseline value.	Baseline and approximately 3 months after baseline

Collaborators and Investigators

• Sponsor: Nanjing Children's Hospital
• Investigators: Principal Investigator: Yubing Wang, Nanjing Children's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2026
• Primary Completion (Estimated): April 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: September 10, 2026
• First Submitted That Met QC Criteria: September 16, 2026
• First Posted (Actual): September 17, 2026

Study Record Updates

• Last Update Posted (Actual): September 17, 2026
• Last Update Submitted That Met QC Criteria: September 16, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Obesity; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Pediatric Obesity
• Other Study ID Numbers: 202604063-2

Drug and device information, study documents

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