Comparison of Intermittent Fasting and Caloric Deficit for Weight Loss in Women With Polycystic Ovarian Syndrome

Inclusion Criteria: * PCOS as described by Rotterdam's criteria Exclusion Criteria: * endocrine disorders * diabetic * hypertensive * Taking medications affecting weight or energy intake/energy expenditure in the last 6 months, including weight loss medications, antipsychotic drugs or other medications as determined by the study physician; * The body weight fluctuated more than 5% in recent 3 months. * Liver and kidney dysfunction: renal impairment, creatinine clearance rate \< 30 mL/min/1.73 m2, transaminase increased, more than three times higher than the normal limit; * History of serious cardiovascular or cerebrovascular disease (angina, myocardial infarction or stroke) in the past 6 months; * History of thyroid diseases; * pregnant * Currently participating in weight loss programs or weight change in the past 3 months (\> 5% current body weight) * Patients who cannot be followed for 16 months (due to a health situation or migration) * Patients who are unwilling or unable to give informed consent