The Physicians Committee

Fiber is the Key to Good Health

  February 18, 2015    


Fiber plays a key role for digestion, weight loss, and cancer prevention, and can even increase lifespan! But don’t be fooled—many packaged food companies are trying to boost sales by adding extra fiber to their gummy candy or yogurt, but the best source of fiber is plants themselves! Yes, natural fiber is found only in fruits, vegetables, whole grains, and legumes. So make sure you’re filling your plate with whole, plant-based foods.

What is fiber?

There are two types of fiber: soluble and insoluble. Soluble fiber is found in oats, beans and other legumes, and some fruits and vegetables. Soluble fiber lowers cholesterol levels. Insoluble fiber—found in whole grains, fruits and vegetables, kidney beans, and bran—acts like a broom, cleaning your digestive tract.

Both types of fiber are only found in plant foods—meat and dairy products contain no natural fiber. Don’t be fooled by yogurts that prominently advertise their fiber content! That fiber was added during processing. Since dairy products are high in saturated fat and cholesterol, skip the yogurt and head to the produce aisle. Just one cup of raspberries has 8 grams of fiber! One cup of red lentils has 16 grams of fiber—and 18 grams of protein.

15030-NTR American Heart Month-Twitter-Red Lentils v1

Weight Loss

If you’re looking to lose weight, filling up on fiber-rich foods is your best bet. My colleagues and I recently published a study in the Journal of the Academy of Nutrition and Dietetics showing that simply switching to a plant-based diet leads to significant weight loss, without any calorie counting or exercise.

Cancer Prevention

Not only can fiber help you shed pounds or relieve your digestive woes, it can decrease cancer risk. By improving the intestinal transit of food and waste, fiber helps your body eliminate carcinogens. The U.S. Polyp Prevention Trial also found that a high-fiber diet reduced the occurrence of colon polyps. A meta-analysis published in the Journal of the National Cancer Institute examined 13 studies and found that the risk of colorectal cancer decreased as fiber intake increased.

How Can I Get Enough Fiber Each Day?

I recommend a dietary intake of 40 grams of fiber per day—while most Americans are only getting 10-15 grams. But there’s no need to count. It’s easy to boost your fiber content with a few easy swaps. Trade white bread for whole grains. Ditch sugary cereals for heart-healthy oatmeal. Add some fruit to your breakfast or grab an apple or banana when you’re in a hurry. Make sure that everything on your plate has at least a little bit of fiber. Most importantly, skip the animal products. When your menu is plant-strong, you’ll be getting the fiber you need.

Want to see how your fiber intake measures up? Fill out our Fiber Checklist!


Soluble fiber lowers cholesterol levels. Insoluble fiber—found in whole grains, fruits and vegetables, kidney beans, and bran—acts like a broom, cleaning your digestive tract.

I'm 73 years old, I'm 271.6 Lbs I'm on a low 1. Calories 2. Fat 3. Sodium 4. High Fiber diet . What food and drinks I can have ? I feel I'm a lousing battle.

eat from the four groups: fruits of any kind even bananas and grapes, and plenty of them, vegetables greens, of all varieties and potatoes too. Beans and whole grains like brown rice. Eat lots, don't add oils. And go for a 20 minute walk per day or longer :) no meat, no dairy and no eggs they're fattening and unhealthy. Google freelee the banana girl, durian rider, happy healthy vegans for more tips :)

I'm 78-years old and have been eating this way for three years after being vegetarian for the previous 20. Believe me this is NOT a losing battle but you do have to learn how to cook because you cannot find the foods you need in restaurants! Having said this there are many excellent low-fat vegan cookbooks, blogs and websites. Just type 'fat-free vegan recipes' in your browser window and voila!


So true. You must learn how to cook. One recipe at a time. It is well worth it to learn.


Thank you for this blog! My mom is a 77-year-old vegetarian for the past 2 years. Her health is top notch due to her plant-based diet and several short walks in her condo community daily. Your information and Netflix documentaries have been lifesaving for her.

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