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Completed

NCT Number: NCT07682571

Research on the Needs, Feasibility, and Intervention Effects of AI Health Coach-based Just-in-Time Adaptive Intervention (JITAI) in Weight Management for Overweight/Obese Adults

This pilot study evaluates the needs, feasibility, and preliminary effects of an artificial intelligence (AI) health coach-based just-in-time adaptive intervention for weight management in adults with overweight or obesity.

Participants receive a wearable device and use a WeChat-based platform during the intervention period. The system collects wearable data and self-reported information, and provides timely behavior-change support related to physical activity, sedentary behavior, sleep, diet self-monitoring, and weight-management self-regulation. The AI health coach provides conversational support and personalized suggestions based on predefined intervention rules and participant inputs.

The main purpose of this study is to assess whether this AI-supported intervention is feasible and acceptable for adults with overweight or obesity. The study also explores changes in weight-related outcomes, health behaviors, self-efficacy, sleep, and quality of life before and after the intervention.

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Key information

Conditions

Overweight , Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

4th Affiliated Hospital, School of Medicine, Zhejiang University

Yiwu, Zhejiang, 322000, China

About this study

Overweight and obesity are common chronic health problems that require sustained support for daily behavior change. Digital health interventions may help extend weight-management support into everyday life, but many existing programs rely on generic education, retrospective feedback, or burdensome manual self-monitoring. This study evaluates an AI health coach-based just-in-time adaptive intervention designed to provide timely and individualized support for weight-management behaviors.

This is a single-arm pilot study conducted among adults with overweight or obesity. Participants use a wearable device and a WeChat-based intervention platform during the study period. The intervention combines passive wearable sensing, participant-reported dietary self-monitoring, rule-based just-in-time intervention triggers, and an AI conversational health coach. Intervention content focuses on physical activity, sedentary behavior, sleep-related routines, dietary self-monitoring, and self-regulation for weight management.

The AI health coach provides conversational guidance, encouragement, and behavior-change suggestions. Intervention messages are generated or selected based on participant data and predefined rules, with the goal of delivering support at moments when participants may benefit from timely prompts or feedback.

The study evaluates feasibility and acceptability indicators, including wearable use, participant engagement, dietary self-monitoring, and interaction with the AI health coach. Preliminary intervention effects are explored by comparing baseline and post-intervention measures, including weight-related outcomes, body composition, physical activity, sleep, eating-related self-efficacy, and quality of life. The findings will inform the refinement of AI-supported just-in-time adaptive interventions for future controlled trials in weight management.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged 18 to 60 years.
  • Body mass index of 24 kg/m2 or higher, meeting the Chinese criteria for overweight or obesity.
  • Able to use a smartphone, WeChat-based platform, and wearable device during the study period.
  • Willing to participate in the AI health coach-based just-in-time adaptive intervention and complete study assessments.
  • Provided written informed consent.

Exclusion criteria

  • Pregnancy, lactation, or planning pregnancy during the study period.
  • Severe cardiovascular, cerebrovascular, hepatic, renal, endocrine, psychiatric, or other major diseases that may affect study participation or safety.
  • Medical conditions or medications that may substantially affect body weight or body composition.
  • Contraindications to physical activity or inability to complete the intervention procedures.
  • Current participation in another weight-management intervention or clinical study.
  • Inability to understand the study procedures or complete the required assessments.

Treatment and study plan

AI Health Coach-based Just-in-Time Adaptive Intervention

Behavioral

The intervention provided timely behavior-change support for weight management through an AI health coach delivered via a WeChat-based platform. The system used wearable device data and participant inputs to support physical activity, sedentary behavior reduction, sleep-related routines, dietary self-monitoring, and self-regulation. Participants received conversational guidance, encouragement, and personalized suggestions based on predefined intervention rules and participant data.

Other names: JITAI

Primary outcomes

  1. Participant retention rate

    Time frame: From enrollment to post-intervention assessment, approximately 31 days

    Retention rate was defined as the proportion of enrolled participants who completed the post-intervention assessment.

  2. Valid wearable use rate

    Time frame: During the 31-day intervention period

    Valid wearable use rate was defined as the proportion of intervention days with valid wearable data. A valid wearable day was defined as a day with at least 10 hours of wear time or at least 180 minutes of main sleep data.

  3. Active engagement rate

    Time frame: During the 31-day intervention period

    Active engagement rate was defined as the proportion of intervention days on which participants had at least one interaction with the AI health coach or at least one dietary self-monitoring record.

  4. Acceptability of the AI health coach-based intervention

    Time frame: Post-intervention assessment, approximately 31 days

    Acceptability was assessed using a post-intervention questionnaire evaluating participants' perceived usefulness, satisfaction, and willingness to continue using the AI health coach-based intervention. Higher scores indicate greater acceptability.

Secondary outcomes

  1. Change in body weight

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Body weight was measured at baseline and post-intervention. The outcome was the change in body weight from baseline to post-intervention.

  2. Change in body mass index

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Body mass index was calculated from measured body weight and height. The outcome was the change in body mass index from baseline to post-intervention.

  3. Change in body fat percentage

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Body fat percentage was measured at baseline and post-intervention. The outcome was the change in body fat percentage from baseline to post-intervention.

  4. Change in waist circumference

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Waist circumference was measured at baseline and post-intervention. The outcome was the change in waist circumference from baseline to post-intervention.

  5. Change in visceral fat level

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Visceral fat level was measured at baseline and post-intervention. The outcome was the change in visceral fat level from baseline to post-intervention.

  6. Change in physical activity

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Physical activity was assessed using the International Physical Activity Questionnaire-Short Form. The outcome was the change in physical activity from baseline to post-intervention.

  7. Change in sleep quality

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Sleep quality was assessed using the Chinese version of the Pittsburgh Sleep Quality Index. The outcome was the change in sleep quality score from baseline to post-intervention.

  8. Change in eating self-efficacy

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Eating self-efficacy was assessed using the Chinese version of the Weight Efficacy Lifestyle Questionnaire-Short Form. The outcome was the change in eating self-efficacy score from baseline to post-intervention.

  9. Change in health-related quality of life

    Time frame: Baseline and post-intervention assessment, approximately 31 days

    Health-related quality of life was assessed using the EQ-5D-5L. The outcome was the change in health-related quality of life from baseline to post-intervention.

Sponsors and collaborators

Lead sponsor

The Fourth Affiliated Hospital of Zhejiang University School of Medicine

Other

Registry information

Important dates

Study start
2026
Primary completion
2026
Study completion
2026
First posted
Jul 6, 2026
Registry last updated
Jul 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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