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Get excited about nutrition, and learn as you go with these information-packed resources on a wide variety of nutrition-centric topics! Our bistroMD experts review the importance of the macronutrients protein, fat, and carbohydrates, as well as how to make them work most efficiently for you.

Know Your Macronutrients: Fiber

"Fiber this, fiber that..." But do you know what fiber actually is? From answering "Is fiber a carbohydrate?" to identifying dietary fiber sources, familiarize yourself with all things fiber!

Know Your Macronutrients: Fiber

What Are Carbs?

Carbohydrate is one of the three macronutrients, with protein and fat being the other two. Macronutrients in foods are large dietary components that supply the body with energy in the form of calories, while carbohydrates tend to be largest fuel source in the Americanized diet. Though the general U.S. population obtains their carb intake mostly from added sugars, not all carbohydrates exist in sugary snacks and sweet treats. Nutritious carbs come from plant-based and nutritious sources, including whole grains, legumes, fruits and veggies, while dairy milk and products also supply the macronutrient. That being said, dismissing refined products and embracing naturally-occurring carb sources is encouraged to reap the macronutrient's benefits, including digestive and heart health, all of which are closely tied to fiber.

So, What Is Fiber?

Dietary fiber is a type of carbohydrate found in plants. But unlike macronutrients that supply calories, fiber cannot be absorbed or digested and travels down the gastrointestinal tract mostly intact. Fiber is further divided into two forms, including soluble and insoluble fibers:

Soluble Fiber
Soluble fiber can be thought of as a sponge, absorbing with water and creating a gel. The When this type of fiber is ingested, it can bind with cholesterol and excrete it from the body, ultimately paralleling with the health statement "Eat fiber to reduce cholesterol." Soluble fiber is found in those notorious cholesterol-lowering Cheerios along with oats and beans.

Insoluble Fiber
Unlike soluble fiber, insoluble fiber does not bind with water and remains entirely intact in the gastrointestinal tract. Insoluble fiber contributes to stool bulk and promotes regularity and is found in fibrous vegetables, nuts, and popcorn.

Benefits of Dietary Fiber and A High-Fiber Diet

Supports Digestive Health
Perhaps the most recognized benefit of fiber relates to digestive health and bowel regularity. Adequate intake of fiber has shown to reduce the risk of diseases of the colon, including hemorrhoids, diverticulosis, and colon cancer.

Decreases Heart Disease Risk
The notion that fiber reduces cholesterol is mostly related to soluble fiber, as it demonstrates the ability to bind to "bad" or LDL cholesterol and excrete it from the body. Evidence also supports fiber helps reduce blood pressure levels, thus lowering the risk of heart disease.

Promotes A Healthy Weight
Fiber's role in satiety can promote a healthy weight by controlling hunger levels. And not to mention, high-fiber foods tend to be lower in calories. Research has shown individuals who consume a high-fiber diet have more successful weight loss results and maintain a healthy body mass index (BMI).

Controls Blood Sugar
Fiber has shown to help manage and control blood sugars, particularly by improving the body's response to insulin.

Reduces Cancer Risk
Along with reducing the risk of colon cancer, a high-fiber diet has shown to be protective against mouth, throat, esophageal, and breast cancers according the Physician's Committee.

How to Increase Fiber Intake

Did you know the average American consumes 15 grams of fiber per day? Considering the daily recommendation of 38 and 25 grams of fiber for men and women, respectively, the U.S. is falling shy of intake and puts itself at a greater risk of developing chronic diseases. Increase fiber intake and reap the benefits with these tips and advices:

Gradually Increase Fiber
Suddenly increasing fiber intake right out of the gate can cause gastrointestinal upset, including cramping, diarrhea, and gas. Particularly if current fiber intake is low, gradually increase it into your diet over a six to eight-week timespan to reduce such risks.

Drink Plenty of Water
Though hydration is encouraged for good health, it is important to drink plenty of water when increasing water intake, as not enough increases the risk of constipation. Healthy adults should aim for at least eight, 8-ounces cups of water daily.

Go for Whole Grains
As a general rule of thumb, go for whole grains; the more processing foods undergo, the less fiber the food supplies. So instead of resorting to a sugary bowl of cereal, swap it out for fiber-packed oats topped with berries and nuts.

Increase Fruit and Veggie Intake
Fruits and veggies are some of the richest fiber sources, especially in their whole form and with the peel. Fiber-rich produce includes apples, bananas, berries, pears, avocadoes, broccoli, cauliflower, and potatoes.

Experiment with Vegetarian Meals
While adopting a vegetarian or vegan lifestyle is individualized, there is great benefit of plant-based meals. Try experimenting with vegetarian meals, as beans, nuts, and seeds supply a generous amount of fiber along with contributing plant-based protein. Find more vegetarian ideas and inspiration here.

Munch on High-Fiber Snacks
Not only will including fiber in your snacks subdue hunger levels, but increase total daily fiber intake. Ditch the bags of chips and make the most out of your snacks, including popcorn, veggies and hummus, or a piece of fruit.

Tread Cautiously with Fiber Supplements
Although a fiber supplement can be valuable, nutrition experts encourage the consumption of whole, fiber-rich foods over them. It is important to not allow the attraction of a supplement validate its use, as they may be devoid of nutrients and costly in price. A dietitian can guide you to an effective and safe product if interested in or warranted to a fiber supplement.

Sydney Lappe's Photo
Written By Sydney Lappe, MS, RDN. Published on November 07, 2012. Updated on April 18, 2019.


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