The Role That Diet Plays in PCOS

by Walter Futterweit, MD, FACP and Martha McKittrick, RD, CDE


PCOS (polycystic ovary syndrome) is a metabolic disorder that affects between 5 and 7.5 percent of all women. It is the number-one cause of infertility, and if left untreated, can increase risk of endometrial cancer. In addition, women with PCOS are at a greater risk for heart disease and diabetes. Until recently, diet was not thought of as an important adjunct in treatment. However, since the fairly recent discovery regarding the role insulin resistance plays in PCOS, many experts now believe that diet should be a part of the treatment plan. Although further research is needed, it is believed that diet can help reduce insulin resistance, which can not only help the symptoms of erratic periods, excessive body and facial hair, and acne, but may decrease the risk of heart disease and diabetes as well. This article will discuss the role of diet in PCOS and give practical suggestions for meal planning.

Role of Insulin in PCOS

Exactly why and how PCOS develops is not quite clear. Most experts, however, now agree that insulin plays a major role. Insulin is a powerful hormone that is released by the body's pancreas in response to eating food.especially carbohydrates. It transports sugar out of the blood and into muscle, fat, and liver cells, where it is converted to energy or stored as fat. Many women with PCOS have insulin resistance. This means that the process of getting the sugar out of the blood and into the cells is defective.the cells are "resistant" to insulin. The pancreas must secrete more and more insulin to get sugar out of the blood and into the cells. High levels of insulin or hyperinsulinemia, can wreak havoc in the body, causing any or all of the following conditions: polycystic ovaries, weight gain and/or difficulty losing weight, increased risk of heart disease by increasing LDL and triglycerides, decreasing HDL and increasing clotting factors.

The discovery of insulin's role in PCOS has brought hopes for better treatment. Treatment is no longer just aimed at treating the individual concerns (i.e. erratic menses, hirsutism, acne, etc.), but instead is now aimed at treating one of the underlying causes -- insulin resistance. If insulin resistance is present, it is best treated with diet, exercise and weight loss if needed. Insulin sensitizing medications may be used as well. Most physicians prefer to start with diet and exercise and turn to drugs if needed. Keep in mind that not all women with PCOS have hyperinsulinemia, but the majority do.

Why Don't the Typical Low-Fat Weight-Loss Diets Work?

Approximately 50 to 60 percent of women with PCOS are obese. It has been shown that losing even five percent of their body weight can lead to an improvement in skin, regularity of menstrual cycles, and decreased insulin levels. However many women with PCOS experience difficulty losing weight, possibly due to high insulin levels, which promotes fat storage. The standard low-fat, high-carbohydrate, weight-loss diet may not be the best approach for women with PCOS. High intakes of carbohydrates, especially refined carbohydrates (e.g., sweets, white bread, white rice, etc.) will quickly turn to sugar and cause elevated levels of insulin. Since high levels of insulin can cause a multitude of problems for women with PCOS, a better diet would be a low-glycemic index diet. This is a diet that includes foods or combinations of foods that do not cause a rapid rise in blood sugar. The low-glycemic diet will be discussed more in detail later in this article.