Carbohydrates and Their Role in Nutrition for PCOS

As a registered dietitian nutritionist who counsels women with polycystic ovary syndrome regularly, one of the most common questions I get from women is about carbohydrates. So many women with PCOS fear carbohydrates. While it is important to monitor your type and amount of carbohydrates, there is no reason to fear them as they offer important nutrients for PCOS. Here's what to know. 

Healthy food spread out on a cutting board
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What Are Carbohydrates?

Carbohydrates are made up of groups of molecules, known as saccharides. These saccharides contain carbon, hydrogen and oxygen atoms in different combinations. There are two main classes of carbohydrates: simple and complex.

Simple carbohydrates have one or two saccharides (mono- and di-saccharides, respectively) linked together. They are primarily the sugars, found in fruit, honey, milk (as lactose) and commercial sweeteners.

Complex carbohydrates contain many saccharides (polysaccharides) and are known as the starches and fibers found in vegetables, grains, and legumes. Complex carbohydrates tend to have a lower glycemic index or rise in blood glucose.

The Role of Carbohydrates in the Body

The primary role of carbohydrates is to provide energy for the body. The breakdown of glucose within the cells produces molecules of energy that can be used. Glucose is the preferred source of energy within the body, although protein and fat can be used if necessary.

Once energy needs are met, glucose is stored in the liver as glycogen. It can be diverted to making other compounds, such as ribose (found in DNA and RNA) and hyaluronic acid (used to lubricate the joints). Excess glucose is converted to triglycerides and stored in fatty tissue as fat.

How Does the Body Use Carbohydrates? 

The process of digestion begins begins in the mouth with physical breakdown (chewing) and salivary amylase, an enzyme which breaks down carbohydrates. In the stomach, carbohydrates are broken down into their monosaccharide components. Most digestion occurs in the small intestine as the mass of food is exposed to special enzymes. Starch is digested in a much slower fashion than simple carbohydrates.

The human body lacks the necessary enzymes to break down dietary fiber, or "roughage," a key component of plant type foods. Instead, fiber is broken down into water, gas, and other components by bacteria in the intestinal tract, slowing the movement of food leading to a feeling of being full.

Once the carbohydrates are broken down into their monosaccharide or simpler components, the liver works in conjunction with the pancreas to regulate blood sugar. The liver stores extra glucose in the form of glycogen and when glucose is needed in the body, it releases it into the blood.

The liver then controls the secretion of glucose into the bloodstream. If the blood concentration is too high, the pancreas secretes insulin to move glucose into the cells and out of the bloodstream. If the blood glucose level begins to fall, glucagon is secreted to increase the amount of glucose that the liver secretes back into the blood.

Food Sources of Carbohydrates

The following foods contain carbohydrates:

  • Grains
  • Fruit
  • Vegetables
  • Beans and legumes
  • Milk and yogurt

Grains contain the highest amount of carbohydrates per serving, with varying amounts of fiber. Whole grain and bran products have higher fiber than white and refined grains. Vegetables contain carbohydrates mostly in the form of starches. Certain vegetables, known as starchy vegetables, such as beans, peas, corn, and potatoes contain higher levels of starch. Watery or non-starchy vegetables such as lettuce, eggplant, and squash contain lesser concentrations of starch. Fruits contain mostly sugars, though the skins do contain a good deal of fiber. 

How Many Carbohydrates Should I Eat Each Day?

While no specific recommendations have been set, it is estimated that 50% to 60% of calories should come from carbohydrates, specifically complex carbohydrates. Since women with PCOS tend to have higher rates of insulin resistance, some experts recommended that they eat slightly fewer carbohydrates, perhaps under 50% of total calories.

The Institute of Medicine's Dietary Reference Intake for fiber for the average adult is as follows:

  • 25 grams (g) per day for females
  • 28 g per day for pregnant women
  • 29 g per day for lactating women
  • 38 g per day for males

The 2020-2025 Dietary Guidelines for Americans recommend limiting simple or added sugars to 10% of total calories. That means that in an average diet of 1,800 calories, 900 to 1,080 calories should come from carbohydrates, and sugar should be limited to 45 g per day.

A healthy diet should contain up to six 1-ounce servings of carbohydrates (with half of them whole grains), 2 to 3 cups of vegetables, and 1 1/2 to 2 cups of fruit each day.

Select green-leafy vegetables whenever possible, and try to limit starchy vegetables like peas, corn, and potatoes if you want to reduce carbohydrate intake. Fruit makes a great dessert or snack instead of processed sugars like cookies or cake.

Try to avoid white and refined grains (which have less fiber), and choose instead whole-grain bread, pasta, and cereals. By selecting healthy carbohydrates and monitoring calories, nothing has to be off-limits. But be aware of the calories that sweets and carbohydrates are contributing to your daily intake.

For personalized diet advice, consult with a registered dietitian nutritionist skilled in PCOS.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. University of California, San Francisco. The liver and blood sugar.

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By Nicole Galan, RN
Nicole Galan, RN, is a registered nurse and the author of "The Everything Fertility Book."