The Best High-Fiber and Low-Carb Foods

Get Your Daily Fiber Intake in More Than 30 Low-Carb Foods

Assorted cereals, flour and grains in piles, bowls and scoops
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How can you find foods that are low in carbohydrate, yet high in fiber? Interestingly, almost all the non-starchy vegetables and low-sugar fruits are the ones that are highest in both fiber and nutrients. A well-constructed low-carb diet emphasizes vegetables and other sources of fiber. You can get the recommended daily amount of fiber on a low-carb diet by choosing those items.

Does Fiber “Count” As a Carbohydrate?

Although most fiber sources are carbohydrates, fiber doesn’t raise blood glucose, so low-carb diets don’t “count” fiber.

Fiber can provide calories, not as glucose, but as products of fermentation in the colon. In fact, fiber helps to moderate the effect of “usable carbs” on the bloodstream, so it furthers the goals of low-carb diets. To the extent that it creates satiety, it may also help prevent weight gain, and aid in weight loss.

High-Fiber and Low-Carb Foods

If you are limiting carbs, look at the ratio of usable carb (or effective or net carb) compared to fiber. In other words, how much carbohydrate do you have to eat to get a gram of fiber? Here is a list, roughly in order on this carb/fiber scale.

Almost All Fiber

  • Flax Seeds: There is almost no usable carbohydrate in flax seeds. It is very high in both soluble and insoluble fiber (about one-third of the fiber is soluble). Flax is high in nutrients and could be the ultimate low-carb fiber source. One tablespoon ground flax has 2.0 grams of carbohydrate, 1.9 of which is fiber.
  • Chia Seeds: These have a fiber and carb profile similar to flax seeds. Find out more about chia seeds and how to serve them.
  • Vegetables that are close to all fiber: Mustard greens, chicory, endive.

More Fiber Than Usable Carbohydrate

  • Wheat Bran: 1/2 cup raw wheat bran has 3 grams usable carb, 6 grams fiber.
  • Unsweetened Coconut and Coconut Flour: 1 ounce unsweetened coconut has 2 grams usable carb, 5 grams fiber.
  • High Fiber Cereals: Check the labels carefully, but some high fiber cereals are also low or fairly low in carbohydrate.
  • Collard Greens: 1 cup chopped, cooked collard greens has 4 grams usable carb, 5 grams fiber.
  • Avocado, Hass: 1 medium avocado has 3 grams usable carb, 12 grams fiber.
  • Spinach and Chard (cooked) 1 cup chopped, cooked spinach has 3 grams usable carb, 4 grams fiber. (Six cups of raw spinach or chard produces about 1 cup cooked).
  • Spinach (frozen): 1 10 oz package spinach has 3 grams usable carb, 8 grams fiber. 
  • Broccoli (cooked): 1/2 cup chopped, cooked broccoli has 1 gram usable carb, 3 grams fiber.
  • Broccoli (raw): 1 cup chopped, raw has 4 grams usable carb, 2 grams fiber.
  • Cauliflower (cooked): 1/2 cup pieces, cooked cauliflower has 1 gram usable carb, 2 grams fiber.
  • Cauliflower (raw): 1 cup raw, cauliflower has 2 grams usable carb, 2.5 grams fiber.
  • Blackberries: 1 cup of raw blackberries has 6 grams usable carb, 8 grams fiber.

About as Much Usable Carb As Fiber

  • Asparagus: 1/2 cup pieces of asparagus has 2 grams usable carbs, 2 grams fiber.
  • Celery: 1 cup chopped celery has 1.5 grams usable carb, 1.5 grams fiber.
  • Eggplant (raw): 1 cup raw eggplant, cubed has 2 grams usable fiber, 3 grams fiber.
  • Eggplant (cooked): 1 cup cubed eggplant, cooked has 5 grams usable carb, 3 grams fiber.
  • Lettuce, Romaine: 1 cup shredded Romaine lettuce has.5 gram usable carb, 1 gram fiber.
  • Mushrooms: 1 cup raw sliced mushrooms has 1 gram usable carb, 1 gram fiber.
  • Radishes: 1 cup raw sliced radishes has 2 grams usable carb, 2 grams fiber.
  • Red Raspberries: 1 cup of raw red raspberries has 7 grams usable carb, 8 grams fiber.

High Fiber, but Not as Much Fiber As Usable Carb

  • Rice Bran: 1/4 cup rice bran has 8 grams usable carb, 6 grams fiber.
  • Cabbage (raw): 1 cup raw chopped cabbage has 3 grams usable carb, 2 grams fiber.
  • Cabbage (cooked): 1/2 cup cooked chopped cabbage has 2 grams usable carb 1 gram fiber.
  • Bell Peppers: 1 cup raw chopped bell peppers has 4 grams usable carb, 3 grams fiber.
  • Snow Peas (edible pod): 1 cup whole raw snow peas has 3 grams usable carb, 2 grams fiber.
  • Zucchini Squash and Other Summer Squashes: 1 cup cooked sliced summer squash has 4 grams usable carb, 3 grams fiber.
  • Nuts and Seeds: Nuts and seeds vary, but most are high in fiber.
  • Strawberries: 1/2 cup of sliced strawberries has 5 grams usable carb, 2 grams fiber.

How Much Fiber Should You Eat?

The Academy of Nutrition and Dietetics recommends adult women consume 25 grams of total fiber per day and adult men consume 38 grams, with 10 to 15 grams coming from soluble fiber. You need less fiber as you age, so over age 50, women should consume 21 grams and men should consume 30 grams. Most people have a much lower fiber intake than is recommended. Our prehistoric ancestors probably ate upwards of 100 grams of fiber per day, so we probably can handle very high amounts of fiber without difficulty.

What About Fiber Supplements?

While fiber supplements (in some circumstances) can be helpful additions to a high-quality nutritious diet, they should never stand in for high-fiber foods, which are also rich in antioxidants and other nutrients essential to health. There is some evidence that simply taking pure fiber as a pill or sprinkling high fiber additions over your food doesn’t carry all the same benefits as when it is in food. Also, some high-fiber additives such as wheat bran contain compounds (phytates) which block the absorption of some nutrients, so large amounts of this should be avoided.

Guidelines for Consuming Fiber

  • If you are unused to eating a lot of fiber, increase amounts gradually to prevent intestinal distress.
  • Make sure you drink lots of water when taking fiber supplements or eating high-fiber foods, as all fiber absorbs at least some water. Fiber can, in rare cases, cause choking or constipation if eaten with insufficient fluid.
  • Since large amounts of fiber can reduce absorption of some medications, it is best to take medication either an hour before or two hours after the fiber.
  • Chitin and chitosan come from the shells of crustaceans and should be avoided by people allergic to seafood.

A Word From Verywell

You won't lack for good sources of fiber when you are on a low-carb diet if you incorporate more vegetables, fruit, and bran in your meal plans. Your plate will be more colorful and appealing and you can enjoy a great variety of food.

Sources:

Dahl WJ, Stewart ML. Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber. Journal of the Academy of Nutrition and Dietetics. 2015;115(11):1861-1870. doi:10.1016/j.jand.2015.09.003.

Improving Your Health With Fiber. Cleveland Clinic. https://my.clevelandclinic.org/health/articles/improving-your-health-with-fiber.

Mcrorie JW. Evidence-Based Approach to Fiber Supplements and Clinically Meaningful Health Benefits, Part 2. Nutrition Today. 2015;50(2):90-97. doi:10.1097/nt.0000000000000089. 

USDA Food Composition Database. United States Department of Agriculture. https://ndb.nal.usda.gov/ndb/search/list.

Wald A. Patient Education: High-fiber diet (Beyond the Basics). UpToDate. https://www.uptodate.com/contents/high-fiber-diet-beyond-the-basics.

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