Fiber can influence many aspects of health.

From gut bacteria to weight loss, it is often considered a fundamental part of a healthy diet.

Most people have a very basic understanding of fiber, and tend to lump it all into one category.

However, the truth is that not all fiber is created equal.

Some types are highly beneficial, while others can cause digestive problems in some people.

This article explains everything you need to know about the different types of fiber.

What is Fiber and How is it Classified?
“Fiber” refers to a diverse group of carbohydrates that humans can not digest.

We lack the digestive enzymes required to break them down, so they pass through most of the digestive system unchanged.

The recommended intake is 38 grams for men, and 25 grams for women. However, most people are only eating around half of that, or 15-17 grams per day (1, 2).

Fiber is mostly found in plant foods, including vegetables, fruits, legumes, whole grains, nuts and seeds (for more details, here is a list of 22 high-fiber foods).

There is actually a huge variety of different fibers found in foods.

The problem is that they are often classified in different ways, which can be highly confusing.

Fiber is formally classified into two main types (3):

Dietary fiber: Fiber found naturally in foods.
Functional fiber: Fiber that is extracted and isolated from whole foods, then added to processed foods.
However, there is a major problem with classifying fiber in this way. It tells us absolutely nothing about their health effects.

A popular alternative method is to classify fiber based on its solubility (soluble vs insoluble), viscosity (viscous vs non-viscous) and fermentability (fermentable vs non-fermentable).

Then there is yet another class of nutrients called resistant starches, which are often classified as dietary fibers.