You’ve heard about the importance of fiber in your diet because of its many benefits—it keeps you regular, creates feelings of satiety, supports the digestive system, and helps in lowering cholesterol. However, do you know some of the other important roles it plays?
Aside from the roughage that sweeps through your digestive tract, pushing remaining contents through the body, how is fiber in its different forms affecting how your body functions? Fiber reduces obesity by slowing down digestion to reducing heart disease and certain types of cancers to serving as the food source for your inner bacterial ecosystem as explained in Digestive Wellness: How to Strengthen the Immune System and Prevent Disease Through Health Digestion by Elizabeth Lipski Ph.D., CCN. Fiber does all this and more! Let’s take a deep dive into the mysterious workings of fiber, shed light on the best sources, and discover ways to tend to your digestive garden within.
What Is Fiber?
First, what is fiber? It’s what some call roughage. It can be described as an indigestible material in the food you eat that passes through your body largely unchanged through the stomach and intestines.
Soluble and Insoluble Fiber
There are two main types of fiber—soluble and insoluble. To create a visual, think of soluble fiber as a gel-like substance that dissolves in water that helps you feel fuller longer. Now, think of insoluble fiber as the rough stuff that doesn’t dissolve in water and stays intact when moving through the colon—it fills up space in your stomach.
Both soluble and insoluble fiber are found in various foods and work as a team to make some serious magic happen. When it comes to ensuring you’re getting enough of both types of fiber, “There’s no need to worry about counting grams of soluble and insoluble fiber,” explains Elizabeth Lipski, Ph.D., CCN. Both types are mixed in many whole foods especially fruits and vegetables, so if you eat a variety of high-fiber foods, you will naturally get both.
Fiber Leads to Better Health
Fiber researchers like surgeon Dr. Denis Burkitt, known as the father of the fiber hypothesis, was the first researcher to connect a high-fiber diet with better health in the 1970s. "He noticed that people eating a traditional African diet in rural areas had almost no diabetes, colon cancer, or heart disease," says Elizabeth Lipski, Ph.D., in her book Digestive Wellness. The discoveries have continued to expand. For instance, the fiber composition of foods has been linked to reduced risk of cardiovascular disease, obesity, stroke, and metabolic dysfunctions, including prediabetes and type 2 diabetes, and some cancers.
Additionally, we know that fiber feeds the trillions of microbes in the gut, so when fiber content is low, it can result in “waves of extinction” as the varieties of microbes fall dramatically. There is mounting evidence that fiber-poor diets have the ability to disrupt the balance of gut bugs. Gut bugs, also known as microbes, are the oldest and most diverse life forms on earth, and they are everywhere! They are in the food in our fridge, in the air we breathe, and live around and inside us.
They also produce short-chain fatty acids (SFCAs). Research shows that SFCAs act as key sources that impact immune function and inflammation in tissues. Scientists say SFCAs play an influential role behind the increasing rates of diabetes, obesity and psychological conditions like anxiety and depression. A lack of fiber in your diet, however, can drastically curb the production of SFCAs.
Add Back Fiber to Your Diet
Fiber is a key ingredient that is removed from food sources when they go through the refining process. Fiber is removed to change the texture of food and make it taste “better.”
The average daily dietary fiber intake in the U.S. is about 16 grams, with adult females having a slightly higher dietary fiber intake than males, according to the United States Department of Agriculture. Fiber intake recommendations from the Institute of Medicine (IOM) range from 19 grams to 38 grams per day, depending on gender and age. However, most adults still need to boost dietary fiber since only 1 in 20 adults actually eat within the recommended range on a regular basis.
By contrast, your Paleolithic ancestors exceeded 100 grams of fiber per day. Interestingly, there is one small African tribe who exceed this consumption level, taking in a whopping 80–150 grams of fiber each day; they are the Hadza, a small hunter-gatherer tribe in Tanzania. Their intestinal microbial diversity is extensive because of the variety of fiber they consume year-round. The abundance of fiber-rich foods in the Hadza tribe comes from tubers, berries, roots, leaves, and other high-fiber foraged plant foods.
Fiber Feeds Good Bacteria
What’s fascinating is that when you make changes to your diet—like shifting from a low-fiber diet to high-fiber diet—changes in the gut microbes can be detected within days.
Emeran Mayer, a gastroenterologist, neuroscientist, and author of The Mind-Gut Connection, explains in his book that you have trillions of bacteria affecting everything from your mood, mind, and thoughts—even how your brain ages and develops. Justin Sonnenburg, a microbiologist at Stanford University, another leading researcher in the field stated in Environmental Nutrition Health, “There is no aspect of human biology that doesn’t get touched in some way by the microbiota. Most of the microbiota are located in the gut, where they have an incredible impact on the body.” What is the food source of these important bacteria? You guessed it—fiber!
In learning about the immense impact of the little microbial companions on your daily health, and how the prevalence of a variety of fiber impacts diversity and overall health, let’s explore some high-fiber foods you can start adding into your daily regimen to support your body from the inside out.
4 High-Fiber Categories of Foods
Since gut bacteria thrive on what on what they eat—if you feed them real, fresh, whole foods, they will grow. If they are fed junk foods, the bad bacteria will grow and yield toxins. This study showed the toxins from harmful bacteria in the gut promote obesity and insulin resistance. With that said, after learning about the vital role fiber plays in supporting the growth of good bacteria toward keeping the inner ecosystem alive and well, it’s time to give fiber the credit it deserves. Here’s to bringing back high-fiber foods that help you flourish!
Rich sources of fiber include a wide variety of vegetables, whole grains, fruits, legumes, nuts, and seeds—all supporting the diversity of your gut microbes. Select organically grown when possible.
- Vegetables: Each 1/2 cup (cooked or raw) usually provides 2–4 grams of dietary fiber.
- Whole grains: Each 1/2 cup (or 1 ounce) serving of whole grains provide 2–4 grams of dietary fiber (examples include brown rice, quinoa, bulgur, millet, buckwheat, barley, spelt, and oats).
- Legumes: Dried beans, peas, and lentils are concentrated sources of fiber, with 6–8 grams per half-cup (cooked).
- Nuts and seeds: A 1.5 ounce serving of most nuts and seeds provides about 3 grams of fiber.
5 Fiber-Boosting Strategies
Individuals whose diets mainly consist of low-fiber foods like white bread, pizza, and pasta need to be careful when adding more fibrous foods into their diets. A sudden switch will overwhelm their underfed bacterial community, resulting in a symphony of sounds and sensations from down below, according to Dr. Giulia Enders, author of Gut: The Inside Story of Our Body’s Most Underrated Organ. “The sudden change will freak the bacteria out, and they will metabolize everything they can in a fit of euphoria. So the best strategy gradually increases the amount of dietary fiber and not feed your bacteria with massive, unmanageable amounts.”
What are the keys to a successful shift in total fiber intake? Start slowly with some of the simple strategies below.
- Mind the bean. Though they are the bomb when it comes to fiber content, they can wreak havoc on your belly. Cook your beans with kombu (edible kelp) to reduce the gas-producing effects beans can have. Add lentils to pasta sauce or soup; they cook quickly without presoaking.
- Load up on veggies. Add raw, cooked, or frozen high-fiber vegetables to homemade or prepared soups.
- Enjoy fresh fruit. Berries offer the best bang for your buck—they are high in fiber, low in sugar, and loaded with many nutrients and protective powers like helping to delay the decline in memory and other neurogenerative diseases. What is a simple way to increase consumption? Add high-fiber fruits, such as fresh or frozen berries to plain yogurt instead of choosing fruit-flavored yogurts with little fruit content.
- Get nutty and seedy. Top salads and mixed dishes with nuts and seeds instead of croutons. Alternatively, add seeds (like chia) to your breakfast cereal or to smoothies.
- Pair beans and grains. A veggie burger is a wonderful way to eat beans and grains together, says Jill Nussinow, M.S., R.D., author of Nutrition CHAMPS: The Veggie Queen’s Guide to Eating & Cooking for Optimum Health, Happiness, Energy & Vitality. She suggests cooking brown rice and lentils (or any combination of whole grain and bean). You can also make a veggie burger by adding mushrooms, onion, sun-dried tomato, and a seasoning of choice—Italian, Thai curry, Middle Eastern, or Mexican.
More Fiber for Better Health
Increasing fiber works wonders in how your body functions. Fiber-filled foods are like fertilizer for your internal garden in more ways than one, leaving you feeling better from top to bottom.
*Editor’s Note: The information in this article is intended for your educational use only; does not necessarily reflect the opinions of the Chopra Center's Mind-Body Medical Group; and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition and before undertaking any diet, supplement, fitness, or other health program.
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