Insoluble versus Soluble Fiber and Why It Matters

If you’re like most people, your understanding of fiber is limited to the fact that it, ahem, moves things along when you’re backed up. So, yes, the bathroom stuff is true, but that’s not the end-all, be-all of fiber. First of all, there are two kinds of fiber, and both of them are so important for health, digestion, disease prevention, and longevity. Here’s what to know about insoluble versus soluble fiber, and why it matters.

Fiber 101

Impromptu health lesson—fiber is a carbohydrate that we get from plant-based foods. But our small intestines can’t digest fiber like it does other carbs, meaning it’s not a big fuel source. Instead, it plays a different role.

Usually, there’s some combination of both soluble and insoluble fiber in your average fruit, veggie, grain, nut or seed, though they tend to be richer in one type than the other. And that’s a good thing, because our bodies need both kinds of fiber to stay healthy.

So what’s the difference?

Soluble fiber attracts water and turns to gel during digestion, which slows down the entire process. That deceleration slows down the absorption of key substances that need a leisurely pace to be safe for our bodies. One example is the rate at which carbs enter the bloodstream. Too much too fast leads to a spike in blood sugar after a meal. It’s the difference between eating an orange—high in soluble fiber—and downing a glass of orange juice—low in soluble fiber. Without the benefit of that fiber, the OJ creates a blood sugar spike that will turn into an energy crash or hunger pangs.

There’s also a weight management component. Since soluble fiber slows down digestion, you’ll feel fuller for longer after a meal rich in fiber.

Another benefit of soluble fiber is its influence on the absorption of both dietary fat and cholesterol. People at risk of heart disease are often told to include lots of soluble fiber because it can help lower the amount of LDL cholesterol (the bad one) in the blood. This kind of fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables, like yams, potatoes, winter squash, and beets. It’s also in psyllium, a common fiber supplement. Pro tip—oats have the highest proportion of soluble fiber of any grain!

Insoluble fiber is its own animal. The tell is in the name—insoluble fiber doesn’t gel in water, like soluble fiber does. Instead, it appears to help food pass more quickly through the stomach and intestines and adds bulk. So this is one you’ll need to remedy a bad case of constipation or if you’re experiencing irregularity. Like its soluble sibling, insoluble fiber can help you feel satisfied for longer after a meal, simply because its bulk takes up more space. You’ll find this kind of fiber in foods such as wheat bran, nuts, whole grains, and veggies like green beans and cauliflower.

Here’s a good way to remember the difference: imagine you’re putting the fiber source in a cup of water and walking away for an hour. If there’s no change (think a stalk of celery in that cup), you’re looking at insoluble fiber. If it changes, like a mess of soggy oats from all that water absorption, it’s soluble fiber. Makes sense, right?

Eat Your Fiber

While it’s helpful to know what differentiates insoluble from soluble fiber, don’t get too hung up on which is which. The key takeaway is that overall fiber consumption, because as we’ve established, fiber should be an important part of your diet. And Bumpin Blends makes it easy!

Metamorphosis, Magic Matcha, Banana Nut, Berry Awake, Blueberry Blues, Cinnamon Toast Shrink, Cookie Dough, Ginger Snaps, Green Mango, Magic Cherries, PB&J, Peanut Butter Cup, Pear-y Nice, Pineapple Ginger, Strawberry Fields, Strawberry Superwoman, Thin Mint, Watermelon Cooler, and Watermelon in Paradise (whew!) are all great sources of fiber, with the added benefits of being both wildly convenient and downright delicious. All the better to have your fiber and eat it, too! Check out our menu options here, or build a fiber-rich bundle right this way.