Dietary Composition in Restoring Reproductive and Metabolic Physiology in Overweight Women with Polycystic Ovary Syndrome

TLDR

In a randomized trial, overweight women with PCOS received either a high‑protein (40 % carbohydrate, 30 % protein) or low‑protein (55 % carbohydrate, 15 % protein) diet for 12 weeks of ~6000 kJ/day energy restriction followed by 4 weeks of weight maintenance. The intervention produced pregnancies (two in the high‑protein group, one in the low‑protein group), improved menstrual cyclicity, lipid profile, and insulin resistance, and reduced weight (7.5 %) and abdominal fat (12.5 %) regardless of protein level, with weight loss driving cardiovascular and reproductive benefits and a high‑protein diet yielding only modest additional endocrine effects.

Abstract

Overweight women with polycystic ovary syndrome (PCOS) were randomized to a high protein (HP; 40% carbohydrate and 30% protein; n = 14) or a low protein (LP; 55% carbohydrate and 15% protein) diet (n = 14). The intervention consisted of 12 wk of energy restriction (∼6000 kJ/d), followed by 4 wk of weight maintenance. Pregnancies (two HP and one LP); improvements in menstrual cyclicity, lipid profile, and insulin resistance (as measured by the homeostasis model); and decreases in weight (7.5%) and abdominal fat (12.5%) occurred independently of diet composition. Improvements in menstrual cyclicity were associated with greater decreases in insulin resistance and fasting insulin (P = 0.011). On the LP diet, high density lipoprotein cholesterol decreased 10% during energy restriction (P = 0.008), and the free androgen index increased 44% in weight maintenance stages (P = 0.027). Weight loss leads to improvements in cardiovascular and reproductive parameters potentially mediated by improvements in surrogate measures of insulin resistance. An HP weight loss diet may result in minor differential endocrine and metabolic improvements.