What is fiber? And is fiber essential for an optimal human diet?
According to the Oxford Dictionary, fiber is defined as “dietary material containing substances such as cellulose, lignin, and pectin, that are resistant to the action of digestive enzymes.” In translation, it is indigestible to the human body. That doesn’t necessarily mean it’s bad for you, but it is by no means essential for the human diet.
What are the two types of fiber?
There are two kinds of fiber:
(1) soluble fiber
(2) insoluble fiber
Soluble fiber mixes with water in the stomach, producing a gel-like substance. It can reduce blood sugar spikes, and is found in plant foods. Sources of soluble fiber include: beans, Brussels sprouts, avocados, potatoes, broccoli, turnips, pears, blueberries, and more. If you suffer from digestive issues like Crohn’s or colitis, soluble fiber tends to be less harsh on the stomach than insoluble fiber.
On the contrary, insoluble fiber does not mix with the water and moves through the intestines mostly intact. Insoluble fiber can cause a lot of strain on the intestines, especially if you have IBD. Sources of insoluble fiber include raw vegetables, seeds, and nuts. Some examples could be almonds, pistachios, cashews, carrots, kale, spinach, seaweed, and more.
My experience and recommendation:
From my experience, insoluble fiber specifically is incredibly difficult for my stomach to digest. I’ve had terrible experiences nuts, seaweed, spinach and kale specifically. When I first tried a high fat diet, I snacked a lot on nuts and it eventually led to a flare-up. At this point in my life, I 100% avoid foods that are rich in insoluble fiber. To reduce insoluble fiber in vegetables, cooking them renders them more digestible.
The Push for a High Fiber Diet:
During the 1950s, a new “discovery” came about. The discovery was that a high fiber diet could improve the overall health for Americans. It all began with Dr. Denis Burkitt. He was a surgeon curious to why so many Americans were experiencing diverticulosis. Diverticulosis is a condition where small irritations that develop along the intestinal tract. In an attempt to further educate himself, he traveled to Africa to compare and contrast the lifestyle of Africans to the lives of Americans. He observed that these indigenous people ate lots of fiber and experienced multiple bowel movements per day. Dr. Burkitt concluded that high fiber content in their diet was responsible for their health and longevity. The fiber was coming from nuts, seeds, and other plant foods.
Although it was a great observation, it is by no means a conclusion. Things are rarely that simple. The environment in Africa is very different from the environment in the United States. The air is less polluted in Africa. Africa’s soil is more nutrient dense. All of their African sources of fiber are organic. These Africans weren’t eating a standard American diet of burgers, fries, and refined sugar. On top of those variables, half the U.S. population was smoking cigarettes at the time. You would think Dr. Burkitt would have considered these variables before drawing a conclusion. In my opinion, making the claim that fiber is necessary for optimal health is a ridiculous assumption. There are different kinds of fiber that serve different functions. It boggles me that people actually took Dr. Burkitt seriously.
Personally, I think it makes sense to eat more prebiotic, soluble fiber to feed the good bacteria in your stomach. I usually eat around 10 to 20 grams of fiber per day and I have normal bowel movements (1 to 3 times per day). If you don’t believe me, try it for a week! Experiencing these things for yourself is crucial to self-development. It teaches you to question what is deemed “normal.” For more information on the invention of fiber, check out The Fiber Fallacy written by Mike Sheridan.