10 Things You Didn’t Know About Fiber


Last week, I started the first portion of an internship that serves as the capstone of my nutrition degree: my clinical rotation at a local hospital. Thus far, it’s been an eye-opening experience getting my feet wet with performing patient assessments and education, as well as navigating the labyrinth that is charting on electronic medical records. So, since I’ve got my Nutrition Professional hat on–and I even have a lab coat!–I thought I would dive in with another installation in my Things You Didn’t Know Nutrition series. (Can I call it a series? It’s been almost 18 months since the last one…..so a series at a snail’s pace.) This time we’re focusing on……..


Better known as “that stuff that makes you poop”! But if that’s all you think fiber is good for, I have news for you. There’s a lot more to fiber than that! Here are 10 things you might not know about this important component in our food, and why we could do well to get more of it.

Colon Blow

(I’m thinking of using this as my LinkedIn profile pic when I start applying for nutrition jobs. It seems to set the appropriate tone of professionalism and decorum, wouldn’t you say?)

1. Fiber is what your body can’t digest.

Yep. Your body cannot break down fiber, so it traverses your entire GI tract to exit through the gift shop.

2. Fiber is always plant-derived.

Can you think of a fiber-rich animal product? Cheese? Eggs? Grass-fed beef, perhaps? Nope, nope, and nope. Fiber is the part of a plant that gives it structure. So just like cholesterol is only found in animal products, fiber is only found in plant products. (Didn’t think you were gonna learn about cholesterol in this post, too, didja?)

3. So how do some non-plant-based foods contain fiber?

You may have seen some small amount of fiber listed in the Nutrition Facts of primarily animal-derived foods (or other food items you wouldn’t expect to contain a lot of fiber). This is probably due to what’s known as “functional fiber”: when plant-derived fiber is added to fortify non-fiber-rich foods.

4. Insoluble vs. Soluble

What’s the difference between soluble and insoluble fiber? It’s pretty simple: soluble fiber dissolves in water, while insoluble fiber does not. This creates distinctions between the mechanism of action each type takes in your digestive system.

5. Why do whole grains contain more fiber than refined grains?

The bran, or outer shell, of a wheat kernel is the part that contains the majority of the plant’s fiber. When wheat is processed to obtain refined (what we know as “white”) flour, its bran is removed. This is why whole grains contain more fiber, while refined grains contain less.

6. Dietary Recommendations

Current dietary recommendations for adult fiber intake are 38 grams/day for men and 25 grams/day for women. (Don’t ask me why the giant gap between the two.) The average American only gets about 15 grams/day, however–definitely not enough!

7. Why fiber makes you poop

Fiber adds bulk to your stool, causing increased pressure as it “comes down the pipes,” shall we say.

8. Fiber reduces risk of disease

Numerous studies have shown that a diet high in fiber has protective effects against certain types of cancer, especially colon cancer. One study showed that people who got 35 grams/day reduced their risk of colon cancer by 40%. One theory behind this is that fiber helps quickly bind to and remove potential carcinogens from the body.

Fiber has also been shown to lower the risk of heart disease, probably because (similar to the cancer theory) it binds to and removes cholesterol from the gut. Other research reveals that increasing fiber can reduce the risk of stroke, diabetes, and high blood pressure.

9. Fiber reduces risk of death

A recently published study by the National Cancer Institute that included almost 400,000 participants found that for every 10-gram increase in fiber intake, risk of death dropped 12% in men and 15% in women. (Presumably, this means risk of health-related deaths, not like skydiving accidents or anything.)

10. Fiber feeds good bacteria

The good bacteria you want to inhabit your gut feed on dietary fiber. As research has shown, we want to keep these little guys happy! (Check out my post on probiotics for more in-depth info on this topic.) In an absence of fiber to feed on, it’s believed that bacteria may begin to break down the protective mucosa of the stomach, causing inflammation.

 So where do I find fiber?

Okay, this part you may already know, but it’s always good to get a refresher! Whole grains, fruits, vegetables, beans/legumes, and other plant-derived foods are good sources. Here are a few ideas for fiber-rich meal planning:

Banana Chocolate Olive Oil Muffins
Peach-Almond Baked Oatmeal
Whole-Grain Blueberry Orange Muffins
Easy as Apple Pie Baked Oatmeal

Creamy Apple Barley Salad
Chickpea Salad Wraps, Vegetable Feta Tart
Fig, Pear, and Goat Cheese Salad with Cinnamon Pecan Vinaigrette

7-Layer Mexican Tortilla Pie
Lentil Sausage Soup
Spicy Pan-Fried Noodles with Tofu
Pesto Pasta & Bean Salad
Sweet Potato Enchiladas
Couscous Cakes with Feta and Sundried Tomato

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