This study prospectively includes PCOS patients with normal weight and overweight/obesity, closely follows up and intensively manages them, and observes the level and distribution of weight reduction achieved by patients after lifestyle intervention (high-protein diet for weight loss). Additionally, it aims to provide reference for setting weight loss targets for future PCOS patients by comparing the differences in clinical improvement among patients achieving different degrees of weight reduction (\<2% \[equivalent to no weight loss\], 2-5%, 5-10%, ≥10%) at different time points (3 months, 6 months) following dietary intervention. Furthermore, this study will compare the differences in reproductive and metabolic marker improvements between baseline PCOS patients experiencing weight rebound, those who successfully lost weight, and those who experienced weight rebound. This will help explore the impact of weight cycling on PCOS-related manifestations. Finally, at a genetic level, the study will analyze potential mechanisms underlying different outcome indicators by comparing differences in metagenomics, transcriptomics, and metabolomics among patient groups. Ancillary/Nested Sub-study (12-week Precision Nutrition Trial): Within the WHIP cohort, we will conduct a nested, prospective interventional sub-study to evaluate the efficacy of an insulin-resistance-phenotype-guided precision dietary prescription versus a standard guideline-based energy-restricted diet. Eligible participants are women with PCOS and insulin resistance enrolled in the cohort. The sub-study lasts 12 weeks with assessments at baseline and week 12. Primary endpoints include change in HOMA-IR and change in the core11 metabolic risk composite. Secondary endpoints include changes in gonadotropins (FSH, LH), sex steroid hormones (e.g., estradiol, progesterone), and patient-reported symptom scores.