Low-Carb Foods That Will Provide Your Daily Fiber Intake

Finding foods that are low in carbohydrates yet high in fiber may seem like a challenge. However, almost all non-starchy vegetables and low-sugar fruits are also the highest in both fiber and nutrients.

A well-constructed low-carb diet emphasizes vegetables and other sources of fiber. You can still get the recommended daily amount of fiber on a low-carb diet by choosing those items. 

Is Fiber a Carbohydrate?

Although most fiber sources are carbohydrates, fiber doesn’t raise blood glucose, so low-carb diets don’t “count” fiber as a carb for the purpose of tracking carbohydrate intake. However, soluble fiber provides 2 calories for every gram but not as glucose, but as a by-product of fermentation in the colon (called short-chain fatty acids). Insoluble fiber is the only substance that provides bulk without calories.

In fact, fiber helps to moderate the effect of “usable carbs” in your 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.

Fiber is good for your digestive system and the prevention of hypertension as well. It can also maintain healthy levels of LDL cholesterol and blood glucose while keeping your waistline and weight down.

Recommended Daily Fiber

According to the Academy of Nutrition and Dietetics, adult women should consume 25 grams of fiber per day, while adult men should aim for 38 grams. In both cases, 10 to 15 grams should come from soluble fiber. Adequate intake is described as 14 grams of fiber for every 1,000 calories. Comparably, the daily value used for food labels and set by the FDA recommends 25 grams of fiber based on a 2,000 calorie diet.

You need less fiber as you age. Women over the age of 50 should consume 21 grams of fiber per day, and men should have 21 grams. Unfortunately, most people have a much lower fiber intake than is recommended. It is estimated that the average American only consumes 17 grams of fiber per day and only about 5% of the population meets the adequate intake.

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

Two types of seeds are excellent sources of fiber and have very few carbs to worry about. They're great additions to your diet and can be eaten in multiple ways.

• Flax seeds: There is almost no usable carbohydrate in flax seeds. They are 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 grams of carbohydrate, 1.9 of which is fiber.
• Chia seeds: These have a fiber and carb profile similar to flax seeds. Chia seeds can be used in many ways, including as a yogurt additive or salad topping.

More Fiber Than Usable Carbs

The following foods have more fiber than usable carbohydrate, so they're also great choices for a low-carb diet:

• Blackberries: 1 cup raw blackberries has 6 grams usable carb, 8 grams fiber
• Broccoli (cooked): 1/2 cup chopped, cooked broccoli has 2 grams usable carb, 3 grams fiber
• Broccoli (raw): 1 cup of chopped, raw broccoli has 4 grams usable carb, 2 grams fiber
• Cauliflower (cooked): 1/2 cup chopped, cooked cauliflower has 1 gram usable carb, 2 grams fiber
• Cauliflower (raw): 1 cup raw cauliflower has 3.5 grams usable carb, 2 grams fiber
• Collard greens: 1 cup chopped, cooked collard greens has 2 grams usable carb, 6 grams fiber
• Avocado: 150 grams of avocado has 3 grams usable carb, 10 grams fiber
• High-fiber cereals: Check the labels carefully, but some high fiber cereals are also low or fairly low in carbohydrates.
• Spinach and chard (cooked): One cup of chopped, cooked spinach has 2 grams of usable carbs and 8 grams fiber. A 150-gram serving of chard provides 3 grams of usable carbs and 3 grams of fiber. You will need 6 cups of raw spinach or chard to produce about 1 cup after cooking.
• Unsweetened coconut and coconut flour: A 15-gram serving of unsweetened coconut has 2 grams usable carb, 4 grams fiber. A 15-gram serving of coconut flour has 4 grams of usable carbs and 5 grams of fiber.
• Wheat bran (unprocessed): 1/2 cup raw wheat bran has 6 grams usable carb, 12 grams fiber

About as Much Usable Carb as Fiber

These foods have an equal amount of usable carbs and fiber. They offer a perfect balance of the two and are also good choices for your diet.

• Asparagus: 1 cup chopped asparagus has 2 grams usable carbs, 3 grams fiber
• Celery: 1 cup chopped celery has 1.5 grams usable carb, 1.5 grams fiber
• Eggplant (cooked): 1 cup cooked eggplant has 3 grams usable carb, 3 grams fiber
• Mushrooms: 1 cup (155 grams) of mushrooms has 4 gram usable carb, 2 gram fiber
• Radishes: 1 cup raw sliced radishes has 2 grams usable carb, 2 grams fiber
• Red raspberries: 1 cup red raspberries has 8 grams usable carb, 9 grams fiber
• Romaine lettuce: 1 cup raw romaine lettuce has 0.5 gram usable carbs, 1 gram fiber

High Fiber But Less Usable Carbs

Even though these foods are high-fiber, they offer less fiber than usable carbs. They're still healthy, but you do want to keep the carb counts in mind.

• Bell peppers: 1 cup raw, chopped bell peppers has 6 grams usable carb, 3 grams fiber
• Cabbage (cooked): 1/2 cup cooked cabbage has 3 grams usable carb, 2 grams fiber
• Cabbage (raw): 1 cup raw cabbage (89 grams) has 3 grams usable carb, 2 grams fiber
• Nuts and seeds: Nuts and seeds vary, but most are high in fiber.
• Snow peas (edible pod): 1 cup (63 grams) whole, raw snow peas has 3 grams usable carb, 2 grams fiber
• Strawberries: 1/2 cup sliced strawberry halves (76 grams) has 4 grams usable carb, 2 grams fiber
• Zucchini squash and other summer squash: 1 cup cooked summer squash (180 grams) has 5 grams usable carb, 2 grams fiber

Fiber Supplements

In some circumstances, fiber supplements can be helpful additions to a high-quality, nutritious diet. However, they should never take the place of eating high-fiber foods, which are also rich in antioxidants and other nutrients essential to health.

There is some evidence that simply taking fiber supplements in pill or powder form doesn’t carry the same benefits as when it is in food. Also, only the soluble, nonfermenting, gel-forming fiber has been clinically shown to have benefits. Furthermore, supplements are not regulated by the FDA so be certain that a third-party seal is on the packaging such as USP or NSF.

Also, some high-fiber additives, such as wheat bran, contain compounds (phytates) that can block the absorption of some nutrients. Because of this, large amounts of phytates should be avoided.

Chitin and chitosan are common fiber supplements. However, it is derived from the shells of crustaceans and should be avoided anyone who is allergic to seafood.

Guidelines for Consuming Fiber

While fiber is essential to a healthy diet, there are some precautions to consider when increasing your intake.

• Drink lots of water. Fiber can, in rare cases, cause choking (associated with supplements) or constipation if eaten with insufficient fluid. Therefore, be sure to drink plenty of water when taking fiber supplements or eating high-fiber foods.
• Gradually increase consumption. If you are not used to eating a lot of fiber, increase the amount gradually to prevent intestinal distress.
• Take medication long before/after fiber supplements. Since large amounts of fiber can reduce the absorption of some medications, it is best to take medication either an hour before or two hours after the fiber. Follow-up with a registered dietitian or your provider for more details.

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.