How much do you know about fiber? While many recognize that fiber is an important part of a healthy diet, fewer are clear on the specifics—like the difference between soluble fiber and insoluble fiber, for example, or the amount of fiber that should be consumed daily. This is where knowledge really comes in handy: By having an awareness of the facts, you’re arming yourself with the information and tools needed to create a habit that sticks—whether the goal is to make better food choices, break a sweat more often, or just remember to take your multivitamins.
When it comes to the science, there’s no two ways about it: Fiber provides several health benefits and consuming enough of it is important for supporting intake needs of this essential macronutrient. Here’s the catch, though: Despite all evidence pointing to the value and importance of getting enough fiber, most people in the United States aren’t coming anywhere near the recommended levels of daily fiber intake—despite believing otherwise. Recent data reveals that only about 6 percent (yep, you read that right) of the U.S. adult population ages 19-50 meets current recommendations.* (1, 8)
Translation? The fiber intake gap is real. And the first step to bridging it (and consequently reaping the benefits), is to get informed. Here, we break down the two different types of dietary fiber—soluble fiber and insoluble fiber—their unique benefits, and some foods to incorporate from each group. Let’s get down to business!
Fiber 101: Soluble vs. insoluble fiber
Before we dive into the different types of fiber, let’s cover the basics first, starting with fiber itself. Dietary fiber refers to the indigestible part of plant material—that is, the part of plant-based food that passes through the digestive system mostly intact, meaning that it cannot be easily digested, especially in the small intestine. (10)
Dietary fiber is often divided into two groups: Soluble fiber and insoluble fiber. Though they offer different benefits, one thing is clear—they’re both important for supporting digestive health.
Soluble fiber dissolves in water and transforms into a gel-like substance during digestion. “Soluble fiber slows the movement of food through the digestive system and helps prevent certain fats and/or sugars from being broken down and absorbed,” explains Dr. Mastaneh Sharafi, PhD, a registered dietitian and Ritual’s VP of Scientific Affairs. (It’s also present in psyllium, which is commonly used as a fiber supplement.)
Insoluble fiber, on the other hand, does not dissolve in water. “Rather, it draws water, promoting the movement of materials through the digestive tract, resulting in an increased stool bulk,” says Dr. Mastaneh.* (11, 12)
To keep it simple: Soluble fiber dissolves in water, and is shown to help slow digestion and increase the bioavailability of some minerals, while insoluble fiber does not dissolve in water, and is therefore left intact as food moves through the gastrointestinal tract, promoting digestive health. And eating a high-fiber diet—or at the very least, making an effort to include fiber-rich foods on the plate—can help support digestive health.* (9)