Fiber is one of those nutrients you constantly hear about but may not be entirely sure what it is, where it’s found, and what it does for you.
What is fiber?
Fiber is a type of carbohydrate, but since your body cannot digest it, you don’t absorb calories from it. If someone with diabetes or on a low-carb diet is counting carbohydrates, they would subtract grams of fiber from grams of total carbohydrate.
There are two kinds of fiber, soluble and insoluble. Each performs beneficial functions for our bodies and can be found abundantly in whole plant foods. In fact, plant foods are the only foods that contain fiber; animal foods like meat, dairy and eggs contain no fiber.
Soluble fiber is found in foods like oats and fruit. When you eat it, it gels up in your intestines and slows the absorption of nutrients, which is a good thing, especially when it comes to sugar and diabetes. This gelling effect also makes you feel fuller and plays a role in how satisfying a meal is. Consuming soluble fiber in a meal that also contains dietary cholesterol reduces how much cholesterol gets absorbed into your body.
Insoluble fiber is found in vegetables and whole grains and acts like a scrub brush for your intestines. It adds bulk, helping to keep you full and promotes smooth passage of poop through and out of your digestive tract.
How much should I eat?
The daily reference intake (DRI) for fiber intake is 38 grams per day for adult men and 25 grams per day for adult women. Most Americans consume a fraction of this amount. Many people who consume plant-based diets and eat a lot of whole plant foods consume more than the DRI for fiber, which is usually a good thing. However, consuming too much fiber, especially from fiber supplements, can cause gastrointestinal issues. There are also some health conditions which require limiting the amount of fiber you consume, so be sure to check with your health care provider if you have any gastrointestinal issues.
When increasing your fiber intake, take it slow and be sure to consume adequate fluid. You need extra moisture to help move that extra bulk through your digestive tract. Your body needs to time adjust to the extra fiber, so increase your intake gradually over a couple weeks.
What can I eat to add more fiber to my diet?
Here are some examples of meal and snack components to boost your fiber intake. If you base your diet on whole plant foods, consuming enough fiber should be effortless.
1 cup of baby carrots and 2 tbsp of hummus: 5 g fiber
1 apple and 2 tbsp of natural peanut butter: 7 g fiber
Black bean burger on whole grain bun with lettuce, tomato, onion: 11 g fiber
Smoothie with 1 cup almond milk, 1 cup spinach, 1 banana, 1 cup blueberries: 5 g fiber
1 cup lentil chili: 7 g fiber
1 cup whole wheat pasta with ½ cup tomato sauce: 9 g fiber
1 cup quinoa salad with kale and edamame: 9 g fiber
3 oz baked tofu, 1 cup steamed broccoli, 1 baked sweet potato: 8 g fiber
For more information on fiber, check out these resources: