In a recent retrospective study that evaluated the impact of a very-low-calorie ketogenic diet on markers predictive of metabolic and ovulatory dysfunction in women with obesity and PCOS over 12 weeks, a significant decrease in serum anti-Müllerian hormone levels and significant increases in progesterone and sex hormone-binding globulin levels were observed [104]. This evidence concerns the gene SHBG and obesity due to melanocortin 4 receptor deficiency.