This study applied digital technology to a comprehensive lifestyle intervention strategy to design a digital behavioural intervention programme suitable for weight reduction in overweight obese infertile patients in China, and assessed its intervention effect through a randomised controlled trial.The main questions it aims to answer are:

1) Design and implement a digital behavioural weight loss intervention programme; 2) Evaluate the impact of digital behavioural interventions on weight loss outcomes and health outcomes.

Participants will be randomly assigned to a control group and an intervention group.

The control group will receive only routine health education and the intervention group will receive an 8-week digital behavioural intervention. At the end of the intervention, the follow-up period will be one year for reproductive outcomes.

Inclusion Criteria:

1. Fulfilling the World Health Organization diagnostic criteria for infertility, defined as failure to achieve or sustain a clinical pregnancy after ≥1 year of regular unprotected sexual intercourse among couples of reproductive age;
2. patients aged 20-40 years seeking assisted reproductive technology (ART) treatment;
3. Body mass index (BMI) >=24 kg/m²;
4. Willingness to undergo randomization;
5. Absence of significant comorbidities (e.g., uncontrolled hypertension, diabetes mellitus, malignancies);
6. Commitment to participate in and complete the intervention protocol.

Exclusion Criteria:

1. History of major systemic diseases (e.g., cardiovascular disorders, chronic respiratory diseases) or psychiatric disorders (e.g., schizophrenia, major depressive disorder);
2. Current or prior participation in other clinical trials within the past 3 months;
3. Medical contraindications to physical exercise (e.g., severe osteoarthritis, uncontrolled arrhythmias);
4. Previous weight-loss interventions, including pharmacological therapy (e.g., orlistat, liraglutide) or bariatric surgery.