High-Fiber Diet

Author: Allyson Distel, MPH
Last Reviewed: November 15, 2023

What is fiber?

Fiber is found in a part of some foods. It helps the food pass through the digestive system. Fiber does not need to be broken down like proteins and carbohydrates do. Fiber comes from plant-based foods which are vegetables, fruits, and whole grains. There are two types of fiber:

Soluble fiber works with the water you drink and that is found in food. With water, it turns itself into a gel-like consistency. This slows down your digestion because the body needs water to digest food. It can help to lower cholesterol levels. Some examples of foods with soluble fiber are:

  • Fruits such as bananas, apples, blueberries, and oranges.
  • Beans such as kidney, black, and pinto.
  • Oats and barley.

Insoluble fiber helps food to pass through your digestive system and can help your stomach feel full longer. Some examples of foods with insoluble fiber are:

  • Nuts and nut spreads.
  • Vegetables such as cauliflower, carrots, and broccoli.
  • Whole wheat pasta and bread.

A few snack ideas for a high-fiber diet are:

  • Carrots with hummus.
  • Blueberries with Greek yogurt.
  • Celery with peanut butter.
  • Banana with walnuts.
  • Oatmeal with sliced apples.

Eating both soluble and insoluble fiber is important when you are on a high-fiber diet.

What is a high-fiber diet?

A high-fiber diet is when you eat the recommended or more than the suggested daily value of fiber. It is recommended that women should eat 21 to 25 grams of fiber per day and men should eat 30 to 38 grams of fiber per day. You can find how much fiber is in your food by looking at “Dietary Fiber” on the food label.

What are the benefits of a high-fiber diet?

A high-fiber diet can be a healthy option for some people. Keep in mind that when eating fiber you need to drink plenty of fluids. If you don’t, high-fiber foods can cause or worsen constipation. When adding fiber to your diet, you may become bloated and gassy. A diet high in fiber can help prevent some types of cancer and other health issues like obesity, heart disease, and diabetes.

When you have cancer, a high-fiber diet can be helpful. “Gut microbes” are inside the stomach and help to provide the body with nutrients. Eating foods high in fiber while having immunotherapy helps to keep gut microbes healthy. It can also help manage constipation which can be a side effect of some cancer treatments. A high-fiber diet can help move the food you eat through your digestive system and give it bulk, which can promote regular bowel movements. Make sure you are staying hydrated to ensure you don’t become constipated.

Ask your care team if a high-fiber diet is a good idea for you. You can also talk about foods you normally eat to see if they are high in fiber and if you should make any changes.


Health Essentials (2023). 31 High-fiber foods you should be eating. Cleveland Clinic.

Mayo Clinic Staff (2021). Chart of high-fiber foods. Mayo Clinic.

Mayo Clinic Staff (2022). Dietary fiber: essential for a healthy diet. Mayo Clinic.

National Cancer Institute (2021). Constipation: cancer treatment side effect. Gastrointestinal Complications (PDQ) - Health Professional Version.

Thursby, E., & Judge, N. (2017). Introduction to the human gut microbiota. Biochemical Journal. 474(11).

Wein, H (2022). Fiber in diet linked to cancer immunotherapy response. National Institutes of Health.


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