4 Signs You're Eating Too Much Fiber (Yes, It Is Possible)

Physician By Eva Selhub, M.D.
Dr. Eva Selhub is a resiliency expert, physician, author, speaker, scientist, and consultant. She studied medicine at Boston University and is board certified in Internal Medicine.
4 Signs You're Eating Too Much Fiber (Yes, It Is Possible)

Photo by Marko Milovanović

As you likely know, dietary fiber is important for your health, especially for your cardiovascular system, metabolic flexibility, gut health, and the stabilization of blood glucose levels. The average male adult should take in about 30 to 38 grams of fiber a day and for women the recommendation is 21 to 25 grams. And although most people don’t eat enough fiber, consuming too much fiber—especially quickly and over a short period of time—can also be a problem.

Why, you ask? Well, most of the fiber you consume binds to water in the GI tract, which creates a big, soft bulk. The softer the bulk, the easier it passes through the GI tract. Problems arise, however, when there is too much fiber and not enough water. This lack of water can lead to hard bulky stools and the digestive problems that come with them.

Four signs you're overdoing it on the fiber.

These are some of the signs and symptoms that you may be consuming too much fiber too quickly:


1. A change in bowel movements.

Excess fiber can cause constipation or diarrhea. Remember to think of fiber as bulk that attracts water in the GI tract. If you don't have enough fluid in your system or you haven't taken in adequate fluids, dehydration of the GI tract can occur, leading to hardening and difficulty passing the stools. This is especially common when the fiber is primarily soluble fiber like that found in oatmeal, beans, apples, strawberries, or blueberries.

Opposing symptoms, like diarrhea and loose stools, can occur when this bulk is made up of the insoluble fiber found in wheat, corn bran, leafy vegetables, broccoli, and tomatoes. Although adding insoluble fiber to your diet can be a good treatment for constipation, too much consumption of this type of fiber can lead to diarrhea and loose stools—especially if you up your intake all of a sudden, which will push the contents of your GI tract through more quickly.

2. Bloating and gas.

Consuming too much fiber can also create uncomfortable symptoms like bloating and excess production of gas. This most often happens when you eat too much fiber too quickly because most of the fiber won't be digested or broken down while moving through the GI tract. As a result, bacteria that live in the colon digest some of the remaining fiber and create a gas by-product.


3. Abdominal pain.

Along with the change in bowel movements, gas, and bloating, cramping can also occur with too much fiber. This results from too much fiber causing digestion to slow down or stop.

4. Mineral deficiencies.

Fiber is a binding agent, meaning it can also bind to nutrients and cause them to be eliminated before the body has a chance to absorb them. This process most commonly affects iron, chromium, copper, zinc, and calcium absorption. According to some studies, it may be possible to offset this by ensuring that you consume adequate amounts of vitamin C and fish or animal protein.


Here's what to do if fiber is causing you problems.

If you're experiencing any or all of these symptoms, you may be eating too much fiber, consuming it too quickly, consuming the wrong kind of fiber, or be in need of some extra vitamin C and more protein. I suggest you try the following:

1. Do a test.

Try different sources of fiber slowly and at a low dose. If a certain type of fiber causes symptoms at the start, switch to a different source and see if the symptoms recur.


2. Slowly increase your intake.

If you tolerate small amounts of fiber, increase the amount every week or two. When you start experiencing a symptom, decrease the dose for a few weeks. Once the symptoms have been gone for a few weeks, try to slowly increase the dose again until you eventually reach the daily requirements.

3. Switch sources.

If you're experiencing constipation, try switching to insoluble fiber. If you're experiencing loose stools, try switching to soluble fiber.


4. Drink water.

As we learned earlier, the balance between water and fiber in the GI tract is crucial. Ensure that you're drinking water with your intake of fiber—especially if your tendency is to get constipated.

Have questions about fiber? Check out these foods that are surprisingly high in fiber and learn why fiber is just as important as probiotic.

And do you want your passion for wellness to change the world? Become A Functional Nutrition Coach! Enroll today to join our upcoming live office hours.

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