How much fiber should I be eating?

Overview

You may know fiber as one of those dietary components that you should “make sure to get enough of!” But how much is enough? And why does it matter anyway? Read on to learn what fiber does for your body and what foods you can find it in!

What is fiber?

Fiber is a type of carbohydrate found as a structural part of plant foods. Unlike most food components, including other types of carbohydrates, fiber cannot be broken down by the human body. So, instead of being absorbed during digestion, fiber passes through the stomach and intestines mostly intact.

What does fiber do?

There are two types of fiber: soluble and insoluble. Most plants contain both types of fiber but the amount of each will vary.

Soluble fiber dissolves in water and becomes gel-like in the digestive tract. This type of fiber slows down the passage of food as it moves from the stomach through the intestines. Soluble fiber is found in foods such as dried beans, oats, barley, and potatoes.

Insoluble fiber, sometimes known as “roughage”, does not dissolve in water. Instead, it retains water as it moves through the digestive system, helping the body to produce softer, bulkier stools (poops). This type of stool keeps your bowel movements regular. Insoluble fiber is found in foods such as whole grain products, nuts, corn, and berries.

Why should I eat fiber?

Fiber has a number of health benefits, including:

• Promoting regular bowel movements and reducing constipation

• Facilitating weight control by making you feel full longer, thus reducing overeating

• Regulating blood sugar levels by slowing digestion, which prevents blood sugar from spiking too rapidly and can help prevent diabetes

• Lowering cholesterol by binding to cholesterol-containing compounds and removing them from the body

• Preventing intestinal cancer by keeping food moving through the intestinal tract, thus preventing harmful substances from building up

How much fiber should I be eating?

Medical professionals recommend that you eat 20-35 grams of fiber per day, with 10-15 of those grams being soluble fiber. You can hit this goal by including whole grains, fruits, nuts, and other “high-fiber” foods (as defined as containing 5 grams or more per serving) in your diet. Make sure to also drink plenty of fluids when increasing fiber in your diet, since the insoluble fiber retains water during digestion.

On average, Americans eat closer to 15 grams of fiber per day, so there’s definitely room for improvement!

How is fiber related to women's health?

For women in particular, fiber may have additional effects. Fiber has been shown to lower levels of circulating estrogen, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) by reducing reabsorption in the colon and increasing excretion. For this reason, high-fiber diets have shown some association with reduced risk of breast cancer. However, high-fiber diets may also increase the chance of anovulation (failing to ovulate), thus making it more difficult to conceive. Therefore, depending on your phase of life, it may be worth paying attention to the amount of fiber in your diet.

Summary

Fiber is an important dietary component and has a number of immediate and protective benefits. However, many people are not consuming enough fiber, so perhaps it’s time to take stock of your diet! On the other hand, if you’re experiencing anovulation and eating a high-fiber diet, there may be a connection. As always, consult with a doctor or a nutritionist if you have serious concerns or interest in making changes.

Sources

• “Dietary fiber: Essential for a healthy diet.” Mayo Clinic. Mayo Foundation for Medical Education and Research, 2025.

• Gaskins AJ, et al. Effect of daily fiber intake on reproductive function: the BioCycle Study. The American Journal of Clinical Nutrition 90(4):2009.

• “Improving Your Health with Fiber.” Speaking of Women’s Health. Speaking of Women’s Health, 2026.

• “Should I be eating more fiber?” Harvard Health Publishing. Harvard Health Publishing, 2019.