Interestingly, when a Very Low- Calorie Ketogenic Diet (VLCKD) (500–800 kcal, with high-biological-value protein) was administered to reproductive-aged women with PCOS and obesity in a RCT, it proved superior to a mediterranean low calorie diet (1200–1400 kcal) in reducing BMI, fat mass, waist circumference, fasting insulin, HOMA-IR, total cholesterol, and increasing SHBG, leading to decreased free testosterone. This evidence concerns the gene SHBG and polycystic ovary syndrome.