iWAIST Trial: ERCG (Endoscopic Radial Compression Gastroplasty) vs Optimized Lifestyle Intervention for Weight Loss

Inclusion Criteria: * Asian adults aged 18-65 years. * BMI 24.0-37.4kg/m²(Chinese standard)。 * Failed prior conservative weight loss attempts ≥2 months。 * Willingness to comply with follow-up. * Provided written informed consent. Exclusion Criteria: * Prior gastrointestinal surgery with clinically relevant sequelae. * Active or clinically significant gastrointestinal disease, including inflammatory conditions (e.g., esophagitis, Barrett's esophagus, Crohn's disease), peptic ulcer disease (gastric/duodenal ulcer), or neoplastic lesions. * Any condition associated with an increased risk of upper gastrointestinal bleeding. * Hiatal hernia \>2 cm or severe/refractory gastroesophageal reflux disease (GERD); acid reflux requiring ≥2 medications for symptom control. * Esophageal/pharyngeal structural abnormalities that may impede endoscope passage (e.g., stricture, diverticulum). * Achalasia or other severe esophageal motility disorder. * Severe coagulopathy. * Insulin-dependent diabetes mellitus. * Chronic abdominal pain. * Gastrointestinal motility disorder (e.g., gastroparesis). * Hepatic impairment or cirrhosis. * Severe or uncontrolled psychiatric illness. * Alcohol abuse or substance dependence. * Unwilling to participate in a physician-supervised diet/behavior modification program and/or unwilling to comply with routine follow-up. * Daily regular use of NSAIDs, anticoagulants, or other gastric-irritating medications. * Unable or unwilling to take proton pump inhibitor (PPI) therapy as prescribed during the treatment period. * Known or suspected hypersensitivity to any material/component of the study system. * Pregnant or breastfeeding. * Severe cardiopulmonary disease or other serious systemic/organic disease. * Positive Helicobacter pylori (H. pylori) test. * Use of time-critical medications potentially affected by altered gastric emptying (e.g., antiepileptics, antiarrhythmics). * Current systemic corticosteroids, immunosuppressants, or opioid analgesics. * Use of any weight-loss medication within the past 3 months or current use. * Prior use of any intragastric device. * Participation in a weight-affecting clinical trial within the past 6 months. * Symptomatic congestive heart failure, clinically significant arrhythmia, or unstable coronary artery disease. * Clinically significant respiratory disease. * Autoimmune connective tissue disease. * Life expectancy \<1 year or severe renal/hepatic/pulmonary or other serious medical illness. * Known genetic or endocrine cause of obesity (e.g., hypothyroidism, Prader-Willi syndrome) or other endocrine disease known to affect body weight. * Eating disorder (e.g., night eating syndrome, bulimia nervosa, binge eating disorder, compulsive eating).