Increasing fiber intake should be a priority for many of us. But fiber doesn’t need to be the fiber supplement mix from your local drugstore. Many of the healthiest diets naturally contain fiber—except, of course, the carnivore diet. Just know which foods are rich in fiber and when to add them. Here’s what you should know about high-fiber foods.
What is dietary fiber?
Dietary fiber is the part of plant foods that passes through the digestive system, more or less intact. It is a carbohydrate found in fruits, vegetables, grains, nuts, seeds and legumes. Unlike other carbohydrates, fiber is not easily broken down into sugar molecules. Therefore, it does not provide calories or energy to the body. There are two main types of fiber: soluble fiber and insoluble fiber.
soluble fiber Dissolves in water and forms a gel-like substance in the digestive tract. It is known for helping balance cholesterol and blood sugar levels. Foods rich in soluble fiber include oats, beans, and root crops like carrots and sweet potatoes. You can also find it in certain fruits (apples, citrus, and strawberries) and cruciferous vegetables.
insoluble fiber Insoluble in water. Instead, it increases the bulk of your stool. The extra bulk can help with regular bowel movements and can relieve constipation. Foods rich in insoluble fiber include whole grains, green leafy vegetables, cruciferous vegetables and nuts. It is also found in fruits, especially when eaten with the skin on.
You’ll notice that cruciferous vegetables contain both soluble and insoluble fiber. One is not more important than the other. Including both types of fiber can promote digestive tract health, which ultimately affects the health of your entire body.
How much fiber do we really need?
Recommended daily fiber intake varies by age and gender. But the daily intake for adults usually ranges from 25 to 38 grams. Of course, individual needs may vary based on activity level and overall health. The Academy of Nutrition and Dietetics recommends getting about 14 grams of fiber per 1,000 calories per day.
Most Americans don’t get enough fiber in their diets. The modern emphasis on boxed and processed foods means we’re not getting enough whole foods. As a result, Americans only get about half the fiber they should.
If you don’t want to be part of this statistic, be sure to gradually increase your fiber intake. You don’t want to wake up one day and decide to eat a high-fiber diet. Your digestive system may not be ready. It’s also important to get enough water (away from meals) to help avoid digestive discomfort.
Health benefits of a high-fiber diet
better digestive health
Fiber can help prevent constipation by adding bulk to stools. The added volume stimulates bowel movements and therefore promotes regular bowel movements.
Fiber also acts as a prebiotic, feeding beneficial gut bacteria. When bacteria digest certain fibers, they produce what are called “postbiotics.” These short-chain fatty acids (SCFA) provide nutrients to the cells lining the large intestine. As a result, intestinal inflammation can be reduced and intestinal motility improved.
Improving intestinal motility may reduce the risk of colon cancer.
Colon cancer may be avoided
Improving bowel movements may also help you avoid colorectal cancer. A large prospective study of more than 75,000 participants looked at fiber and cancer risk. Higher fiber intake from food is associated with a lower risk of colorectal cancer.
Improve heart health
Increasing your fiber intake may prevent heart disease. Studies show that as insoluble fiber increases, blood pressure and triglyceride levels decrease. Lower fiber intake is also associated with higher insulin levels. No wonder high-fiber cereals are promoted as “heart-healthy.” Whether they are actually the subject of another blog post.
blood sugar balance
Soluble fiber slows the absorption of sugar and helps stabilize blood sugar levels. This slower digestion prevents rapid spikes in blood sugar after a meal. It does this by carefully regulating the release of glucose into the blood. This is important to avoid metabolic syndrome and diabetes.
A high-fiber diet has also been linked to improved insulin sensitivity. Insulin is a hormone responsible for regulating blood sugar levels. Increased insulin sensitivity means cells can use glucose in the blood more efficiently. This also helps maintain stable blood sugar levels and reduces the risk of diabetes.
healthy weight
High-fiber foods often create a feeling of fullness and help control appetite. It may do this by increasing an intestinal hormone called cholecystokinin (CCK). Researchers found that fiber promotes the release of CCK into the bloodstream, which reduces appetite. Therefore, consuming large amounts of fiber may aid in weight loss, if necessary.
A 2023 study examined the success of 4,477 people following a fiber-rich diet over three years. More than 62% of them lost weight. When following a high-fiber diet, the average weight loss was 7.23 pounds (3.28 kilograms).
Which foods have the highest fiber content?
There are several foods that are high in fiber, so there are plenty of options. Incorporating these foods into your diet can certainly support digestive health. However, it can also improve overall health by supporting a healthy immune system.
beans and legumes
Beans, lentils, chickpeas and green peas are excellent sources of fiber. For example, black beans, kidney beans, kidney beans, and pinto beans are particularly high in fiber. According to the USDA Food Information Center, here is the fiber content of three common legumes:
- Peas contain 16.3 grams per cup
- Black beans have 15 grams per cup
- Chickpeas contain 12.5 grams per cup
There are many types of beans, and they are all high in fiber. Lentils are available in green, black and even red. Between beans, lentils, and peas, there are plenty of options to choose from.
Keep in mind that legumes are also rich in lectins, which can damage the digestive system. When I was actively healing from an autoimmune disease, I avoided legumes entirely. This article provides more details and explains some simple ways to reduce lectins and still reap the benefits of legumes.
Whole grains and grain-like seeds
If you eat whole grains, they are also an excellent source of fiber. Oats, brown rice, spelt, einkorn, and barley are high in fiber. Choose whole grain varieties instead of refined grains to increase your fiber intake. Although brown rice is higher in fiber than white rice, our family only eats white rice (here’s why!).
Grain seeds such as quinoa and millet are also good sources of fiber.
certain vegetables
Simply increasing your vegetable intake can increase your fiber intake. Artichokes, broccoli, Brussels sprouts, carrots, kale, and other green leafy vegetables are all high-fiber vegetables. Peas (also legumes) and sweet potatoes both contain high amounts of fiber.
Berries and other fruits
Raspberries, blackberries, strawberries and blueberries are the best sources of fruit. These fruits are also rich in antioxidants, which provide additional health benefits. Pears, apples (with skins), oranges and bananas are also great sources of fiber.
Nuts and seeds
Almonds, chia seeds, flaxseeds, and sunflower seeds are also rich in fiber. You can easily add them to cereal, yogurt, or salads. Chia and flax seeds are also rich in plant-based omega-3 fatty acids.
How do you get enough fiber if you don’t eat grains?
You don’t need to eat whole-grain berries every day to get fiber. If you follow a grain-free or paleo diet, there are still many ways to get fiber beyond whole grains.
- Non-starchy vegetables: Green broccoli, kale, Brussels sprouts, bell peppers, asparagus and cauliflower are high in fiber. They are also Paleo-friendly and provide needed vitamin C.
- Root vegetables: While some people may limit their intake of root vegetables because of their carbohydrates, sweet potatoes and carrots are good sources of fiber.
- fruit: Compared to plums and other fruits, berries are lower in sugar and higher in fiber. Avocados are also a good source of fiber, potassium, and healthy fats.
- Nuts and seeds: Almonds, walnuts, flax seeds, chia seeds, and pumpkin seeds are all “paleo” seeds. They are also a good source of fiber and healthy fats.
- coconut: Coconut products, including coconut meat and coconut flour, are a good source of dietary fiber in paleo recipes.
Who should avoid high-fiber foods?
While fiber is generally beneficial, some people may need to limit high-fiber foods—at least for a while. Here’s who should consider limiting their intake of high-fiber foods:
People with active disease flare-ups
Fiber can aggravate some digestive diseases, such as Crohn’s disease, ulcerative colitis, and diverticulitis. It may be fine during remission, but not during a flare. In this case, you may need to temporarily limit your intake of high-fiber foods as directed by your healthcare provider.
People with chronic IBS or SIBO
People with irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO) may not be able to consume more fiber. They may experience bloating, cramping, or digestive difficulties after adding high-fiber foods. Adjusting the type or amount of fiber may help. For example, following a low-FODMAP diet may reduce symptoms.
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols. It refers to certain carbohydrates that may worsen symptoms in people with these intestinal conditions. Learn more about the low FODMAP diet.
those recovering from surgery
Doctors may recommend a low-fiber diet after certain types of surgery or medical procedures. Gastrointestinal surgery is a good example. After full recovery, it may be better to reintroduce high-fiber foods. Please consult your doctor to determine the condition.
How to add more fiber to your diet
To increase your fiber intake, focus on whole foods. You can also choose to use recipes that contain high-fiber ingredients. Here are some simple ways to get more fiber in your diet:
soups and stews
Add beans, lentils, chickpeas and peas to soups and stews. Or, just focus on recipes that already include beans. Here are some ideas!
Beans are a sure way to increase your fiber intake. You can always add a can or two to vegetable soup to increase the fiber count.
Eat raw vegetables with dipping sauce
For an easy lunch or healthy snack, bring a variety of raw vegetables. Then, pair them with fiber-rich hummus or guacamole. Try your lettuce:
When you pair raw veggies with a fiber-rich dip, you’ll double your efforts!
Enjoy nuts and seeds as a snack
Eat soaked or sprouted nuts and seeds. Almonds, walnuts, pecans, sunflower seeds, and pumpkin seeds are high in fiber and delicious. Bake them and add them to trail mix for a satisfying snack. Chia seeds are easily added as a “pudding”. Try these!
Nuts and seeds also appear as “flour” in grain-free pancakes and baking.
Use Grain-Free Flour Alternatives
Grain-free baking automatically uses high-fiber ingredients like nut flour, seed flour, and coconut flour. Here are some ideas to get you started:
When you move away from white flour and refined pasta, increasing fiber is almost a no-brainer. Enjoy whole, unprocessed fruits and vegetables, and you’ll be surprised how easy (and delicious) it is to consume high-fiber foods.
Have you tried eating a high fiber diet? How can you intentionally eat more fiber every day? Share it with us below!