(HealthDay News) – In lean women with polycystic ovary syndrome (PCOS), eating about half of total daily calories at breakfast rather than dinner improves insulin sensitivity, reduces testosterone levels, and improves the ovulation rate, which may increase fertility, according to a study published in Clinical Science.

Daniela Jakubowicz, MD, from Tel Aviv University in Israel, and colleagues randomly assigned 60 lean women with PCOS to one of two maintenance diets of approximately 1,800kcal but with different meal timing distributions: a breakfast diet (980kcal breakfast, 640kcal lunch, 190kcal dinner) or a dinner diet (190kcal breakfast, 640kcal lunch, 980kcal dinner) for 90 days.

The researchers found that the breakfast diet was associated with a 7% decrease in glucose area under the curve, a 54% decrease in insulin area under the curve, a 50% decrease in free testosterone, and a 105% increase in sex hormone-binding globulin. There was also a 39% decrease in gonadotropin-releasing hormone-stimulated peak serum 17-α-hydroxyprogesterone and an increased ovulation rate in the breakfast diet group.

“In lean PCOS women, a high caloric intake at breakfast with reduced intake at dinner results in improved insulin sensitivity indices and reduced cytochrome P450c17α activity, which ameliorates hyperandrogenism and improves ovulation rate,” Jakubowicz and colleagues conclude.

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