The science has spoken: Dietary fiber provides several benefits to the body, helping to support digestive health, regularity, and satiety. The catch? 94% of Americans are not meeting recommendations for fiber intake, a discrepancy largely attributed to low intakes of vegetables, fruits, and whole grains—food groups that more than 85% of American adults are under-consuming. (With these stats in mind, it may come as no surprise that dietary fiber is considered a “nutrient of public health concern” in the most recent Dietary Guidelines for Americans.)* (1, 2, 7)
To put it simply, the fiber consumption gap is real—and the first step to bridging it is getting informed, not only about fiber's health benefits (and why it’s important to consume enough), but also different sources of fiber, from whole foods to supplements. We’ll cover all that—and more—in this piece.
Fiber 101: What is fiber?
First, let’s talk about fiber itself—namely, what it is and what kinds exist.
Dietary fiber refers to edible fiber that can be sourced from plant foods; specifically, it’s the indigestible part of plant material that passes through the digestive system mostly intact. (This differs from other food components like fat, protein, and non-fiber carbohydrates, which the body can break down and absorb.)
Functional fiber, on the other hand, refers to fiber that is either extracted or isolated from whole foods, then added back to foods or sold as a supplement. (Like dietary fiber, functional fiber also has proven health benefits.). The combination of these fibers—dietary fiber and functional fiber—is referred to as total fiber. (3, 4)
What does fiber do?
Dietary fiber is often classified into two distinct categories: soluble fiber and insoluble fiber. Each serves different purposes in the body. Soluble fiber dissolves in water, forming a gel-like substance that slows the movement of food through the digestive system (and increases the bioavailability of some minerals). Insoluble fiber, as the name suggests, does not dissolve in water. “Insoluble fibers are neither broken down nor absorbed,” explains Dr. Mastaneh Sharafi, PhD, Ritual’s VP of Scientific Affairs and a registered dietitian. “Rather, they draw water as they pass through the digestive tract, resulting in an increased stool bulk.”* (1, 5, 6, 9)
According to Dr. Mastaneh, both types of fiber are beneficial in their own ways—and both can contribute to feelings of fullness. The takeaway? Rather than focusing on specific types, pivoting the goal to get enough fiber overall is a better approach. (Bonus: Most fiber-containing foods contain both soluble and insoluble fiber in differing amounts.)* (1, 5, 6, 9)