This study has two phases:

1. In phase 1 of the study (8 weeks),the effect of two different low calorie diets on manifestations of PCOS, including risk factors for the metabolic syndrome and cardiovascular risk profile will be compared.
2. In phase 2 the long term effect (next 44 weeks) on sustained weight-loss and the above mentioned parameters will be compared and evaluated.

Weight loss is an important and effective treatment of morbidly obese women with PCOS. Effective weight reduction will improve manifestations of PCOS and risk factors for developing type 2 diabetes and coronary heart diseases. We compare the effect of two isocaloric low calorie diets (LCD), - one powder-based shake-diet and a fiber rich diet on the above mentioned parameters. In addition we want to compare the weight-maintenance effect the next 44 weeks of two different follow-up programs: A usual care- and a lifestyle-program.

Inclusion Criteria:

• Woman (European Caucasian)
• PCOS
• BMI = or > 35

Exclusion Criteria:

• Cushing syndrome
• Adrenal hyperplasia
• Androgen-producing tumors
• Anovulation caused by hyperprolactinemia
• Pregnancy, breast feeding
• Use of oral contraceptives/hormone treatment/insulin-sensitizing agents