About Dietary Fiber

Dietary fiber is the part of our food that cannot be digested by human digestive enzymes…

People THINK indigestible means irritating or inflammatory
People THINK indigestible means irritating or inflammatory, but research shows the opposite – indigestible fiber has ANTI-inflammatory effects!

therefore, dietary fiber is correctly said to be ‘indigestible.’ But being indigestible is a GOOD thing! In fact, being indigestible is a very good thing. Indigestible does not mean irritating or inflammatory.

Scientific research has shown that contrary to being inflammatory, fiber has ANTI-inflammatory effects. I am launching Stool School with a report of some of the research already published. Over time, the Stool School blog will draw attention to additional studies from the past and new research as it emerges.

Being indigestible (by human enzymes) means…

Food goes from the mouth to stomach to small intestines to colon before passing out of the body -- my type of Crohn's disease attacks the distal colon.
Food moves from mouth to stomach to small intestines to colon before passing out of the body — non-fiber foods break down early in the digestive system, and fiber foods are broken down later by bacteria. Thus, eating more fiber means more matter passes through the entire intestinal system and out of the body. In an inflamed bowel, a sub-therapeutic increase in fiber means more matter is passed as diarrhea. However, increased diarrhea matter is not an accurate measure of inflammation.

that dietary fiber arrives undigested in the distal intestines. Fiber in the distal intestines becomes the food source for good bacteria. Two great things happen there: 1) good bacteria thrive, and 2) bacterial digestion of fiber creates healing substances (read more in Digger Deeper).

Non-fiber foods break down and absorb through the gut lining early in the digestive system. Fiber treats constipation by adding bulk, which stimulates nerves in the gut to move contents along. Proper transit time stops excessive absorption of water out of the stool. Thus, stool stays soft and is comfortably passed.

Also, the great water-holding capacity of fiber means it soaks up water and holds it like a sponge. Thus, added weight also works with gravity to keep the stool moving through the intestines at the proper speed.

However, resolving constipation is only one of fiber’s roles in the gut.


Fiber can also resolve diarrhea

What most people do not know about fiber is that fiber can also resolve diarrhea, because of its great water-holding capacity. In fact, doctors who specialize in intestinal medicine define diarrhea as not enough water-holding-capacity (fiber) to manage the amount of water in the intestines.1 Also, research has demonstrated that fiber can help correct both too-dry and too-loose stools, and I will post more on this topic over time. Also, I can’t wait to post pages explaining how people I know have capitalized on this knowledge to very quickly stop flares of Crohn’s diarrhea.

Many people also fail to realize that fiber is important for our health outside of the intestinal system. For example, fiber improves blood sugar regulation and cholesterol levels. Fiber also gives a feeling of fullness that helps people feel more satisfied while eating fewer calories. Considering that fewer than 3% of Americans eat the recommended amounts of dietary fiber,2 it’s no wonder we have epidemic levels of obesity and chronic diseases – diabetes and cardiovascular disease.


  1. Fine KD, Schiller LR. AGA technical review on the evaluation and management of chronic diarrhea. Gastroenterology 1999;116:1464-1486.
  2. Agricultural Research Service, U. S. Department of Agriculture. Dietary fiber (g): Usual intakes from food and water, 2003-2006, compared to adequte intakes. What we eat in America, NHANES 2003-2006. Volume 2013, 2010.