The University of Michigan PCOS Intervention Using Nutritional Ketosis

Inclusion Criteria: * We will include women in one PCOS subtype, those having these two symptoms: * Hyperandrogenism - (a) If not on current birth control: hyperandrogenism defined as current elevated total testosterone \>= 50 ng/dL or free androgen index \> 1.5 (ratio of testosterone/SHBG x 100) or severe acne or hirsutism (b) if on current birth control: history from the past 10 years of hyperandrogenism defined as past elevated total testosterone \>= 50 ng/dL or free androgen index \> 1.5 (ratio of testosterone/SHBG x 100) or severe acne or hirsutism * oligomenorrhea-anovulation defined as spontaneous intermenstrual periods of ≥ 45 days or a total of ≤ 8 menses per year. Participants must also be: * overweight or obese (BMI 25-50) * be 21-40 years old * have regular access to the internet * be able to engage in light physical activity * willing and able to follow the assigned intervention. Exclusion Criteria: * a non-English speaker * inability to complete baseline measurements * a substance abuse, mental health, or medical condition that would interfere with participation (such as current chemotherapy) * pregnant or planning to get pregnant in the next 6 months * type 1 or type 2 diabetes * baseline aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \> 2 times normal * baseline renal disease defined as BUN \> 30 mg/dL or serum creatinine \>1.4 mg/dL * baseline uncorrected thyroid disease (TSH \<0.45 mIU/ML or \>4.5 mIU/ML) * breastfeeding or less than 6 months post-partum * planned or history of weight loss surgery * vegan or vegetarian * currently enrolled in a weight loss program or other investigative study that might conflict with this research * taking medications known to cause weight gain or loss * taking hypoglycemic medications other than metformin or medications known to affect metabolism * or patients with other etiologies of anovulation and hyperandrogenism, e.g., Cushing's disease, thyroid dysfunction, elevated prolactin levels, signs of congenital adrenal hyperplasia, organic intra cranial lesion such as a pituitary tumor, or suspected adrenal or ovarian tumor secreting androgens.