Weight Cycling on Hyperandrogenemia and Insulin Resistance in Polycystic Ovary Syndrome

Inclusion Criteria: 1. Women aged 18-45 years in the reproductive period; 2. Women who have previously met the Rotterdam diagnostic criteria (at least 2 of the following 3 criteria have been confirmed, and have been diagnosed with PCOS): 1) Oligomenorrhea and/or anovulation; 2) clinical and/or biochemical evidence of hyperandrogenism; 3) ultrasound showing the presence of unilateral or bilateral polycystic ovaries; 3. Inclusion of 50 women in the normal weight group: 18.5 kg/m² ≤ BMI \< 24 kg/m²; Inclusion of 400 women in the overweight/obese group: BMI ≥ 24 kg/m²; 4. Voluntarily participate in the intervention and sign an informed consent form. Exclusion Criteria: 1. Currently pregnant or lactating, or have had a recent (within 6 months) plan for pregnancy; 2. Currently using known prescription weight loss medications (such as GLP-1RA, orlistat, topiramate, etc.); 3. History of weight loss surgery; 4. History of severe cardiovascular or cerebrovascular diseases; severe liver or kidney dysfunction (ALT \> 3 times the upper limit of normal, or creatinine \> 1.5 times the upper limit of normal); chronic or active gastrointestinal inflammatory diseases; severe systemic diseases; active malignant tumors; 5. Secondary obesity: including hypothalamic or pituitary obesity, obesity secondary to glucocorticoid use, hypogonadism-induced obesity, etc.; 6. Known history of serious endocrine system diseases; 7. Poor compliance with planned dietary interventions (psychiatric disorders such as binge eating disorder, anorexia nervosa, severe anxiety/depression); 8. Unable to follow up on time or deemed non-cooperative by the investigator.