Trial Information

A Reduced Carbohydrate Diet Intervention for PCOS

Polycystic ovary syndrome (PCOS) is a heterogeneous syndrome affecting 5-10% of women of
reproductive age. It is characterized by elevated circulating insulin, reduced insulin
sensitivity, infertility, hyperandrogenism, and a multitude of symptoms that result in a
decreased quality of life. The elevated insulin characteristic of PCOS is likely to play a
major role in its pathogenesis by reducing insulin sensitivity and stimulating testosterone
(T) production and increasing its free fraction. Although many women with PCOS are
overweight/obese (10-50%), those who are non-obese suffer from the same symptoms as their
obese counterparts. Thus, it is likely that the metabolic disturbances associated with PCOS
predispose to weight gain, which in turn exacerbates PCOS by worsening insulin resistance.
Manipulation of dietary carbohydrate quantity and quality (glycemic load; GL) may lower
insulin and improve both reproductive and metabolic outcomes. No study has tested the
efficacy of a lower GL diet among non-obese women with PCOS.

The Specific Aim of this proposal is to determine if a lower GL diet intervention is more
effective than a standard (STD) diet in improving reproductive and metabolic outcomes of
women with PCOS (both normal-weight and overweight/obese). We hypothesize that, in the
absence of weight change, the lower GL diet will be more effective than the STD diet in
decreasing insulin secretion, increasing insulin sensitivity, decreasing free T, decreasing
fat from metabolically harmful sites, decreasing inflammation, and improving menstrual
cyclicity and ovulation. Further, the lower GL diet will increase perceived fullness and
decrease hunger, effects mediated via gut hormones.

Development of a diet that optimizes reproductive and metabolic health among women with PCOS
will reduce reliance on pharmacologic treatments and improve quality of life, even in the
absence of weight loss. This project is novel in being the first to conduct a highly
controlled nutrition intervention in non-obese women with PCOS under weight stable
conditions, utilizing robust measures of insulin secretion and action, fat distribution,
inflammation, hunger/fullness, the gut hormone profile, and reproductive function. The
results from this study can be used as a starting point from which to explore optimal diets
for overweight women with PCOS.