Benefits of Fiber (who should eat fiber and 3 reasons to avoid)


When you read the standard dietary advice, it says to eat 25 to 40 grams of fiber a day for good health. Indeed, taking fiber has a lot of health benefits. BUT does fiber work for everyone?

The fiber recommendation is based on the high fiber intake of many indigenous cultures and the great digestive health that they experience (yet not all indigenous cultures have a high fiber diet).

There are also some great studies showing the benefits of a high fiber diet for weight loss, cardiovascular health, longevity, reduced diabetes risk, and even healthy skin.

Nevertheless, I see many people experiencing negative effects when they eat fiber. This can include many of the symptoms that fiber is supposed to fix like constipation, bloating and other digestive symptoms.

What I’m driving at is that fiber is not a cure for all diseases and can impact an individual’s health in a different way from expected.

In this article, I will explain the best types of fiber to eat, which fiber to avoid, why for some people fiber feels like a poison, and how you can optimize your gut health to be able to tolerate fiber and experience the benefits of fiber.

Does Fiber Intolerance Exist?


For some people, fiber causes gas, bloating, reflux, pain, and constipation and if you follow the conventional advice the answer to this problem is to add more fiber to the diet. This will make the symptoms worse but often that is not linked to the fiber that you are eating as we have been told that we need more fiber if we have IBS symptoms.

This is well described in the book Fiber Menace by Konstantin Monastyrsky, especially all of the reasons why people feel worse eating a higher fiber diet.

People often have much improved IBS symptoms when they switch to the Keto style diet, which is a reduction of carbohydrates  - which means a reduction of fiber in the diet.

 The carnivore diet is another new “trend” where people focus on just eating meat. On one hand, this is not a super healthy option for the long term for many reasons. On the other hand, you can’t argue with the phenomenal health results that people see from doing this in the short term.

 This because of reversing things like insulin resistance of course, but another big reason is the benefits that a low fiber diet can have on a damaged digestive system.

Why Do People Feel Better On A Low Fiber Diet?


Irritable bowel syndrome, which is commonly called IBS, is the most common digestive complaint. Basically, this means that you are experiencing symptoms like bloating, gas, constipation or diarrhea (or commonly both) yet there is nothing physically wrong with you.

If you have digestive symptoms, and your colonoscopy or gastroscopy comes up normal then you are given the label of IBS - but IBS always has a cause and it is identifying that cause which is the key to successful treatment.

One of the best-studied diets to reverse IBS is the low FODMAP diet, and if you are not sure what that is you can read more about it with this low FODMAP article.

The reason that the low FODMAP diet works so well is that it is low in fermentable fiber.

 So does that mean that all of the studies on fiber are wrong and we would all benefit from a low fiber diet?

NO - the reason that a low fiber diet works is that it reduces the food for bacteria in the intestinal tract, and it is an overgrowth of these bacteria that produces the gas that causes the bloating, pain, constipation and diarrhea.

We have trillions of bacteria in our intestinal tract and they are essential for our health, but it is when we get an imbalance in bacteria - or an overgrowth of bacteria in the small intestine, this is known as SIBO that we get the IBS symptoms.

Fiber And SIBO


If you have Small Intestinal Bacteria Overgrowth (SIBO) a high fiber diet is going to “feed” the bacteria overgrowth which will trigger the IBS symptoms.

Besides the uncomfortable IBS symptoms that come with SIBO, you may also experience a number of other health issues that may not seem connected to gut health:

  • Malabsorption
  • Brain fog, anxiety and depression
  • Skin problems
  • Muscle and joint inflammation
  • Migraines

If you feel worse eating fiber it may be a good idea to get tested for SIBO or do a detailed stool analysis to test for gut pathogens and intestinal health markers - for this I prefer the G.I Map test.

Fiber And Your Nervous System


Another reason people may have trouble tolerating fiber is a compromised nervous system, in particular, the vagus nerve which helps to stimulate gut motility.

Fiber helps to provide “bulk” to the stool and can be great for some people with constipation. Fiber can also help to make the stool move easily through the digestive tract, especially if it is high in mucilage (think of psyllium and chia seeds).

BUT if you have a compromised nervous system you will have a stool with plenty of bulk but it won’t move through the digestive tract because of a lack of peristalsis. This is why some fiber supplements will cause more constipation rather than alleviate it.

Does this mean that we should all avoid psyllium and the trendy chia seeds? No, but some people do need to eliminate these foods from the diet, as far as they address the underlying cause of their digestive problems.

How To Test If Fiber Is A Problem For You

Benefits of Fiber (who should eat fiber and 3 reasons to avoid) 1

A low FODMAP diet can be a great way to assess if the fiber is a problem for you. This is not meant to be a long term diet even if you feel great while you are doing it, but a short term solution while you address the underlying cause of your digestion issues.

If you feel great on a low fiber diet you should get assessed for SIBO, Helicobacter pylori, and other gut pathogens so that you can address the underlying cause.

Other low fiber diets include the Specific Carbohydrate Diet (SCD) and the Fast Tract diet.

Benefits of Fiber In Your Diet


After reading the first half of this article you are probably thinking that fiber is something that we should keep to a minimum. BUT this is not the case for everyone and if you have a healthy digestive tract a diet in quality fiber can provide many benefits.

Fiber provides “food” for the bacteria in the large intestine. It is not digested in the small intestine and when it reaches the large intestine it is broken down by the bacteria and this is essential for a healthy microbiome.

There is a lot of research coming out now about how important our gut microbiome is for our overall health. From obesity to depression, there is virtually not a single health issue that is not affected by our gut bacteria. This can be one of the problems with low fiber diets if done for long periods.

Therefore, in many cases, fiber should be considered as one of the main components of your diet. It helps:

  • Maintain a healthy weight
  • Lower cholesterol levels
  • Improve cardiovascular health
  • Reduce the risk of diabetes
  • Enhance mood
  • Treat digestive issues like constipation and diarrhea (if the underlying cause has been addressed)
  • Protect us from cancer

More importantly, that might be not a full list of fiber's perks. Scientists keep investigating the hidden powers of fiber and the way it can optimize our overall health.

Types Of Fiber


We have discussed the pros and cons of consuming fiber, but a few questions remained:

What is fiber? What are the types of fiber and what is the difference between them?

There are two main types of fiber:

  • Soluble fiber
  • Insoluble fiber

Both types of fiber come from plants and are forms of carbohydrate. Soluble and insoluble fibers are equally essential for your digestion and overall health.

The Role Of Soluble Fiber

It draws water into your gut which turns into a gel-like liquid and slows digestion. Also, it helps optimize cholesterol levels and decrease the risk of heart diseases.

The Role Of Insoluble Fiber

Insoluble fiber doesn’t absorb water and passes through the digestive system unchanged. Nevertheless, it is as important as soluble fiber. It positively impacts your intestinal health, reducing the risk of hemorrhoids and constipation.  

Fiber-packed Foods List

There are a lot of natural foods you may eat to increase your intake of fiber. However, very often people are attracted and tricked by colorful packages with “high fiber” cereals. In fact, most of the cereals are highly refined, full of sugar and not as rich in fiber as it is advertised.

In order not to become a victim of false marketing, always look at the label, check the list of ingredients and its nutritional value. And personally, I recommend to cut out processed foods and to put natural foods in your cart.

Keep reading to find out what foods rich in soluble and insoluble fiber to add to add them to your personal grocery list.

Best Sources Of Soluble Fiber

Whole Grains

Most of the whole grains are rich in fiber. Oat, bran, and barley are the highest in soluble fiber. Some other fiber-packed grains to diversify your diet are barley, bulgur, whole wheat spaghetti, wheat germ, and amaranth, one of the "ancient grains".

Nuts & Seeds

Peanuts, almonds and brazil nuts are among the richest sources of fiber you could add to cereals. You may add them to your hot cereals or chop and add to salads or pureed soup.

A handful of Sesame seeds, sunflower seeds or pumpkin seeds can also fuel with fiber. The new trend is flaxseed and chia, which you could add to a refreshing smoothie.

Legumes, Beans, and Peas

Lentils, beans, and peas are fiber-rich superfoods which should be definitely added to your diet. Lima beans, navy beans, kidney beans, and black beans are available almost in any market. You could easily add them to your entrees, salads or soups.


Fruits are vital for your health and indispensable of components of a well-balanced diet.

Many fruits are excellent sources of soluble fiber in the form of pectin:

Pear, apples, bananas, oranges, grapefruits, grapes, pineapple, blueberries, strawberries, raspberries, plums, fresh and dried apricots, cherries, peaches, prunes, raisins, figs, dates and some exotic fruits like mango and guava.

Although, some fruit could be not easy to find or quite pricey, oranges and apples are affordable and available almost in every grocery store.


Just like fruits, vegetables also can give your body a necessary dose of soluble dietary fiber (pectin). Brussels sprouts, broccoli, cabbage, sweet potatoes, avocados, asparagus, parsnips, carrots, spinach, squash, string beans, cabbage, turnips, kale, and zucchini are the best high soluble fiber veggies.

There are vegetables rich in inulin, which is usually sold as a soluble fiber supplement. Inulin can be found in chicory, artichokes, and onions.

Best Sources Of Insoluble Fiber

There are no specific veggies or fruits rich only in insoluble fiber. In fact, high fiber foods contain both soluble and insoluble fiber in a certain amount.

Some foods can brag about a higher percentage of soluble fiber, others have a balance of soluble and insoluble fiber. If you’d like to increase intake of insoluble fiber, consider to add to your grocery list the following foods:

  • Beans
  • Whole wheat flour
  • Wheat bran
  • Green beans
  • Potatoes
  • Cauliflowers
  • Nuts

Prebiotic Supplementation


To nourish your beneficial bacteria and achieve optimal gut health, consuming natural high fiber foods may be not enough. There are five powerful prebiotic supplements that could help you:

  • PHGG promotes stimulates the growth of healthy gut bacteria, reduces stomachache, helps cure constipation and irritable bowel syndrome
  • Lactulose helps relieve constipation (difficulty pooping) and treat hepatic encephalopathy (liver disease). However, don’t abuse it and take only as prescribed in order to avoid side effects like diarrhea, bloating and wind.
  • Arabinogalactan is a beneficial prebiotic supplement for digestive tract health. In addition, it helps with diabetes, boosts the immune system, helps deal with allergies, relieves pain and even has cancer-fighting potential.
  • Fructooligosaccharides (FOS) are considered to be powerful prebiotics and often included in the baby formula to help feed the beneficial bacteria. Also, fructooligosaccharides lower cholesterol levels, reduce blood sugar and cure digestive issues, such as constipation and diarrhea.
  • Inulin is one more prebiotic that plays not the last role in the improvement of digestive health. It promotes balance between bad and good bacteria and helps control diabetes.

Does My Body Need More Fiber?

Before increasing your intake of soluble and insoluble fiber, you should determine your digestive issues if any. There are two main tests that will reveal what's going on with your gut health:

SIBO test is a non-invasive absolutely safe breath test that can be done in the comfort of your home. It will help:

  • Detect an abnormal growth of bacteria in the small intestine.
  • Identify potential health risks associated with an overgrowth of bacteria within the small bowel.
  • Shed the light on the cause of your IBS symptoms.
  • Determine whether you are intolerant to some sugars or carbohydrates, for instance, lactose.
  • Assess the levels of hydrogen-producing bacteria and methane-producing bacteria.

G.I Map Stool test is an FDA-approved DNA-based test for proper analysis of an individual’s microbiome. It can be also easily done at home. Just a single stool sample can help:

  • Detect the real reasons for your digestive problems, including diarrhea, reflux, bloating and constipation.
  • Asses Helicobacter pylori, Zonulin, Candida, yeast infections and other pathogens.
  • Receive information that will help prevent chronic health problems with digestion.

As I’ve mentioned above both the SIBO test and the G.I Map can be done in the privacy of your home. Following simple instructions, you can easily get the needed samples. Then just send us them for further analysis and receive a detailed report with results via email.

Also, you can schedule a call with me and get all your questions answered and results explained. Finally, I will provide you with recommendations on fiber intake and create an elaborate plan on how to fight your health issues.

 Do not hesitate to schedule a call with me today if you’d like to enhance your gut health!

Was this article helpful?

Affiliate Disclosure

This website contains Amazon affiliate links, which means we may receive a percentage of any product or service you purchase using the links in the articles or advertisements. You will pay the same price (or get a discount) for all products and services, and your purchase helps support Planet Naturopath’s ongoing research and work. Thanks for your support!

Planet Naturopath Editorial Policy