If you’ve read any nutrition-focused articles or browsed a grocery aisle in the last few years, you’ve probably come across some of the buzzy benefits of fiber (Fills you up! Aids digestion! Etc!). But there’s one thing about fiber that’s not quite so advertised: the difference between insoluble fiber and insoluble fiber. Seriously, what the heck is soluble fiber, and how do you make sure you’re getting enough?
We talked to a handful of registered dietitians to get the lowdown on the different types of fiber—what they are and what they do—and compiled some of their best advice for making sure you get what you need every day.
Soluble vs insoluble fiber.
Fiber, which is found exclusively in plants, is a type of carbohydrate that your body cannot fully digest. There are two main types of fiber—soluble (also called viscous) and insoluble (also called bulking). Your body handles each type of fiber differently and, because of that, they play different roles in your health.
“Soluble fiber dissolves into a gel-like substance that is important to help capture and remove toxins and cholesterol from the body,” explains Amy Shapiro, M.S., R.D., CDN and founder of Real Nutrition. Insoluble fiber is not digested by the body or absorbed into the bloodstream. Instead, it forms the ‘weight’ and ‘bulk’ of stools in the body, acting as a ‘broom’.