Why Is Fiber Good for You? The Crunchy Truth
Growing evidence shows that adequate fiber intake may benefit your digestion and reduce your risk of chronic disease.
Many of these benefits are mediated by your gut microbiota — the millions of bacteria that live in your digestive system.
However, not all fiber is created equal. Each type has different health effects.
This article explains the evidence-based health benefits of fiber.
Put simply, dietary fiber is a non-digestible carbohydrate found in foods.
It’s split into two broad categories based on its water solubility:
Soluble fiber: Dissolves in water and can be metabolized by the "good" bacteria in the gut.
Insoluble fiber: Does not dissolve in water.
Perhaps a more helpful way to categorize fiber is fermentable versus non-fermentable, which refers to whether friendly gut bacteria can use it or not.
It's important to keep in mind that there are many different types of fiber. Some of them have important health benefits, while others are mostly useless.
There is also a lot of overlap between soluble and insoluble fibers. Some insoluble fibers can be digested by the good bacteria in the intestine, and most foods contain both soluble and insoluble fibers.
Health authorities recommend that men and women eat 38 and 25 grams of fiber per day, respectively.