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The Top Sources of Insoluble Fiber and Why You Need It

Eat more fiber, they say. But why is fiber so important for your health, and are you getting enough of it? Dietary fiber, which includes both soluble or insoluble varieties, is found in whole plant foods such as vegetables, fruit, whole grains, and legumes. Many of us know that sources of insoluble fiber can help prevent or relieve constipation. But dietary fiber benefits go far beyond that. High-fiber foods can also help you maintain a healthy weight and reduce your risk of heart disease, diabetes, and some forms of cancer. As such, it pays to consume the recommended 25-30 grams of fiber per day, ensuring that most of
that amount comes from insoluble fiber. Here we explain more about fiber and why you need it, as well as
what foods to eat to maximize your insoluble fiber intake.

What is Dietary Fiber?

Dietary fiber refers to the parts of whole plant foods your body is unable to digest.
While your body breaks down and absorbs other food components such as proteins, fats, and carbohydrates, it is unable to process dietary fiber in this way. Instead, fiber passes out of your body almost intact after traveling through your stomach, small intestine, and colon. Although it sounds like fiber has little impact on your body, this couldn’t be further from the truth. Your body might not be able to absorb or digest fiber, but eating it provides many benefits for your health.

Soluble vs. Insoluble Fiber

You need to consume both soluble and insoluble fiber for optimal health benefits. But what’s the difference between them?

Soluble Fiber

This type of dietary fiber dissolves in water to form a gel-like substance. It can help lower levels of cholesterol and glucose in the blood. Some good sources of soluble fiber include oats, citrus fruits, carrots, and barley.

Insoluble Fiber

This type of fiber does not dissolve in water. It can help promote the efficient movement of food through your digestive system by increasing stool bulk. Foods containing insoluble fiber include whole-wheat flour, nuts, beans, and a variety of fruits and vegetables.

Why Do We Need Insoluble Fiber?

Both types of fiber have their benefits. Together, they help to increase satiety by slowing down digestion speed and causing the physical sensation of fullness in the stomach and intestines. A high-fiber diet can also reduce the risk of various diseases and issues, including diabetes, obesity, metabolic syndrome, and cardiovascular disease, all of which can have an impact on quality of life and independence. One of the main benefits of a high fiber diet is more stable glucose levels. So, how does fiber help lower blood sugar? It does this by slowing down the digestion rate of other nutrients, such as carbohydrates. Foods containing soluble fiber are less likely to lead to sharp spikes in blood sugar, and can even control and prevent these spikes. Insoluble fiber provides other specific dietary fiber benefits, including the prevention of constipation. Since the body can’t digest insoluble fiber, it stays in the gastrointestinal tract and absorbs fluids and other byproducts. This helps form stools faster and encourages the movement of waste out of the body. By preventing constipation, insoluble fiber also helps lower the risk of hemorrhoids and folds in the colon, and may also reduce the risk of colon cancer.

The Top Sources of Insoluble Fiber

Most whole plant foods are sources of either soluble or insoluble fiber, but some foods are top of their game when it comes to adding fiber to your diet. Whether you’re cooking for yourself, your family, or caring for others, try to incorporate more of these foods high in insoluble fiber:

Leafy Greens

Dark leafy greens pack in a lot of health benefits, not least due to their high-fiber content. A cup of cooked spinach contains around five grams of insoluble fiber, while cooked chard provides around three grams.


As a rule of thumb, fruits you eat with the skin on tend to have more insoluble fiber than fruits you need to peel. Bananas, for example, have insoluble fiber but only around two grams. In comparison, as well as being rich in antioxidants and other nutrients, berries are high in insoluble fiber. Raspberries contain around seven grams per cup, for example, while blackberries contain around six grams of insoluble fiber.


Although raw cauliflower contains insoluble fiber, the amount increases when you cook it. Serve it as a popular side dish for nearly four grams of insoluble fiber per cup.


Prunes are often touted for their ability to resolve constipation. But this is no old wives’ tale – with over 12 grams of insoluble fiber in one cup, they’re worthy of their reputation for getting things moving.


With more than 14 grams of insoluble fiber per cup, almonds make a great high-fiber addition to your diet. Pine nuts follow close behind with 13 grams per cup while peanuts and pistachios pack in around 10 grams per cup.


Peas are great as a simple side dish, but they also work well in pasta salads, stews, and soups. Their versatility comes in especially handy if you’re trying to boost your fiber intake as they contain more than 15 grams of insoluble fiber per cup.


Make sure to eat the peel when you munch on an apple and you’ll benefit from almost three grams of insoluble fiber.


Beans are another excellent source of fiber. Roasted soybeans come out on top with close to 17 grams of soluble fiber per cup, while cooked pinto beans are another good option with around 11 grams per cup.

Your Guide to The Benefits of Insoluble Fiber

As this guide shows, there are plenty of economical, tasty, and versatile foods that are also great sources of insoluble fiber. While you should try to incorporate more of these foods into your diet, it’s important not to suddenly triple your fiber intake overnight. As with most dietary changes, it’s best to build up slowly when it comes to adding fiber to your diet. And this is especially true if you’re cooking for anyone with existing digestive problems. For more information, feel free to contact us today!