The aims of the present study is to examine whether Time-Restricted Feeding (TRF) is a safe and effective regimen to improve insulin resistance and decrease body weight in overweight/obese Polycystic ovary syndrome (PCOS) patients over 16 weeks compared to reduced energy restriction.

Intermittent fasting regimens involve periods fasting followed by periods of eating freely. Time-Restricted Feeding (TRF) is a new form of intermittent fasting and involves shortening the eating window to 4-10 h/day. TRF is a safe lifestyle intervention for weight loss in adults with obesity. Accumulating evidence suggests that TRF is an effective means of decreasing body weight and improving insulin resistance but did not have any negative impact on eating disorder symptoms, body image perception, or eating behaviors. Polycystic ovary syndrome (PCOS) is the most common endocrine condition in productive-aged women. About 60-70 % of women with PCOS are obese or overweight, and obesity is associated with insulin resistance. Since many women with PCOS seem to have insulin resistance, compensatory hyperinsulinemia is thought to contribute to hyperandrogenism by direct stimulation of ovarian production of androgens and by inhibition of liver synthesis of SHGB. It is important to ameliorate insulin resistance in PCOS patients.The aims of the present study is to examine whether TRF is a safe and effective regimen to improve insulin resistance and decrease body weight in overweight/obese PCOS patients.

Inclusion Criteria:

• Age ≥ 18 years
• BMI≥24kg/m2
• Polycystic ovary syndrome has been diagnosed

Exclusion Criteria:

• 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;
• Having been in pregnancy.
• Researchers believe that there are any factors that affect assessing subjects' participation in trial.
• History of malignant tumors;
• History of Cushing's syndrome, hypothyroidism, acromegaly, hypothalamic obesity;
• 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.

Only women have the PCOS.