Objective: Polycystic ovary syndrome (PCOS) is commonly affected by obesity. PCOS phenotypes are prone to increased waist/hip ratio, insulin resistance and dyslipidaemia. This substudy was undertaken to evaluate the effects of lifestyle interventions on metabolic biomarkers in overweight/obese PCOS women and the interventional effects of dietary components related to metabolic outcomes.

Design: Randomized three-arm parallel study.

Patients: Fifty-seven PCOS women body mass index (BMI >27kg/m(2), age 18-40) were randomly assigned to diet (D, n=19), exercise (E, n=19) or diet plus exercise (DE, n=19) in three-arm fashion over 16weeks. The D group received nutritional counselling by a dietician to reduce their energy intake by at least 600kcal/d. The E group received an ambulatory exercise regimen from a physiotherapist. The DE group had both interventions.

Measurements: Self-reported food intake over 4days, exercise pedometers, BMI, waist/hip ratio, blood pressure, body composition and oral glucose tolerance test were performed before and at the end of intervention.

Results: BMI, waist circumference and total cholesterol were significantly reduced in the D and DE groups, as well as low-density lipoprotein and Homeostasis Model of Assessment index in the D group. In the E group, exercise was increased along with a decrease in BMI and waist circumference. The strongest predictor of reduced BMI was increased fibre intake (-0.44, P=.03), while a decrease in trans fatty acid intake predicted reduced insulinogenic index (0.44, P<.01).

Conclusions: Nutritional counselling with dieting is clearly effective to improve metabolic disturbances in overweight/obese women with PCOS. Increased fibre and reduced trans fatty acid intake are primary predictors of metabolic improvement and weight control.