Improving fiber intake should be a top priority for many of us. But fiber doesn’t have to be a fiber supplement from the local drugstore. Most healthful diets naturally include fiber – except, of course, carnivore diets. It’s just a matter of knowing which foods are high in fiber and when to include them. Here’s what you need to know about high-fiber foods.
What is dietary fiber?
Dietary fiber is the part of plant foods that passes through the digestive tract, more or less intact. It is a carbohydrate found in fruits, vegetables, grains, nuts, seeds and legumes. Unlike other carbs, fiber doesn’t easily break down into sugar molecules. Therefore, it does not provide calories or energy to the body. There are two main types of fiber: soluble and insoluble.
soluble fiber Dissolves in water and forms a gel-like substance in the digestive system. It is known to help balance cholesterol and blood sugar levels. Examples of foods rich in soluble fiber are oats, beans, and root crops such as carrots and sweet potatoes. You’ll also find it in some fruits (apples, citrus fruits and strawberries) and cruciferous vegetables.
insoluble fiber Does not dissolve in water. Instead, it adds bulk to the stool. That extra amount can help with regular bowel movements and reduce constipation. Examples of foods rich in insoluble fiber are whole grains, leafy vegetables, cruciferous vegetables, and nuts. It is also found in fruits, especially when eaten with the peel.
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 promotes a healthy digestive system, which ultimately impacts the health of the entire body.
How much fiber do we really need?
Recommended daily fiber intake varies by age and gender. But for adults it is generally between 25 to 38 grams per day. Of course, individual needs may vary depending on activity level and overall health. The Academy of Nutrition and Dietetics recommends getting about 14 grams of fiber for every 1,000 calories per day.
Most Americans don’t get enough fiber in their diets. The modern emphasis on packaged and processed foods means we aren’t getting enough whole foods. As a result, Americans are getting only about half the amount of fiber they should.
If you don’t want to be part of that statistic, make sure to increase your fiber slowly. You don’t want to wake up one day and decide to eat a high-fiber diet. Your digestive system may not be ready for this. It is also important to drink enough water (away from food) to avoid digestive upset.
Health Benefits of High Fiber Diet
better digestive health
Fiber may help prevent constipation by adding bulk to stools. The extra amount stimulates movement in the intestines, so it may promote regular bowel movements.
Fiber can also act as a prebiotic, nourishing beneficial gut bacteria. When bacteria digest certain fibers, they become known as “postbiotics.” These short-chain fatty acids (SCFAs) nourish the cells lining the large intestine. As a result, inflammation of the gut may reduce, and motility may improve.
Improving motility in the intestine may reduce the risk of colon cancer.
Potentially Avoid Colon Cancer
Improving motility in the gut may also help you avoid colon cancer. A large prospective study of more than 75,000 participants looked at fiber and cancer risk. Consuming more fiber from foods was associated with a lower risk of colorectal cancer.
improve heart health
Increasing fiber intake can prevent heart disease. Research shows that as insoluble fiber increases, blood pressure and triglyceride levels decrease. Low fiber intake is also linked to higher insulin levels. It’s no surprise that high-fiber cereals are advertised as “heart-healthy.” Whether they actually are or not is a topic for another blog post.
blood sugar balance
Soluble fiber can slow the absorption of sugar, helping to stabilize blood sugar levels. This slow digestion prevents rapid rises in blood sugar after meals. It does this by carefully controlling glucose release into the bloodstream. This is important to avoid metabolic syndrome and diabetes.
High fiber diets are also linked to improved insulin sensitivity. Insulin is a hormone responsible for controlling blood sugar levels. Increased insulin sensitivity means cells can more effectively use glucose from the bloodstream. It also helps in maintaining stable blood sugar levels, thereby reducing the risk of diabetes.
a healthy weight
High-fiber foods often fill the stomach, which can help control appetite. It may do this by increasing a gut hormone called cholecystokinin (CCK). Researchers have found that fiber promotes the release of CCK into the bloodstream, which reduces appetite. Therefore, including plenty of fiber can help with weight loss if necessary.
A 2023 study looked at the success of a fiber-rich diet in 4,477 people over three years. More than 62% of them lost weight. On the high-fiber diet, the average weight loss was 7.23 pounds (3.28 kg).
Which foods have the most fiber?
Many foods are high in fiber, so there are plenty of options. Including these foods in your diet can definitely help with digestive health. However, it may 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, navy beans, and pinto beans are especially high in fiber. According to the USDA’s FoodData Central, here is the fiber content of three common beans:
- Peas contain 16.3 grams per cup
- Black beans contain 15 grams per cup
- Chickpeas contain 12.5 grams per cup
There are many types of beans and all contain high amounts of fiber. Pulses are available in green, black and even red. Between beans, lentils and peas, there are plenty of options to work with.
Keep in mind that beans also contain high amounts of lectins which can harm the digestive system. When I was actively recovering from an autoimmune disease I avoided beans completely. This article gives more details and suggests some easy ways to reduce lectins and still get the benefits of beans.
whole grains and grain-like seeds
If you eat whole grains, these are also excellent sources of fiber. Oats, brown rice, spelt, einkorn and barley are high in fiber. Choosing whole grain varieties instead of refined grains increases your fiber intake. While brown rice has more fiber than white, our family only eats white rice (here’s why!).
Seeds like quinoa and grains like millet are also good sources of fiber.
Simply increasing your vegetables can improve your fiber intake. artichokes, broccoli, Brussels sprouts, carrots, kale, and other leafy vegetables high fiber vegetables, Peas (also a legume) and sweet potatoes both provide good amounts of fiber.
Berries and other fruits
Raspberries, blackberries, strawberries and blueberries are some great fruit sources. These fruits are also rich in antioxidants, which have additional health benefits. Pears, apples (with peel), oranges and bananas are also good sources of fiber.
nuts and seeds
Almonds, chia seeds, flax seeds and sunflower seeds are also rich in fiber. You can easily add these to cereal, yogurt or salad. Chia and flax seeds are also high in plant-based omega-3 fatty acids.
How to get enough fiber if you don’t eat grains?
You don’t need to eat whole wheat berries every day to get your fiber. If you’re following a grain-free or paleo diet, there are still plenty of ways to get fiber outside of whole grains.
- Non-Starchy Vegetables: Broccoli, kale, Brussels sprouts, bell peppers, asparagus and cauliflower are rich in fiber. They also align with Paleo diet principles, and supply essential vitamin C.
- root vegetables: While some people may limit root vegetables because of the carbs, sweet potatoes and carrots are good sources of fiber.
- Fruit: Compared to plums and other fruits, berries contain less sugar and more fiber. Avocado is also a good source of fiber, potassium and healthy fats.
- nuts and seeds: Almonds, walnuts, flax seeds, chia seeds and pumpkin seeds are “paleo”. They are also a good source of fiber and healthy fats.
- Coconut: Coconut products, including coconut meat and coconut flour, are good sources of dietary fiber in paleo cuisine.
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
Fiber may aggravate certain digestive conditions like Crohn’s disease, ulcerative colitis and diverticulitis. This may be fine during remission but not during flare-ups. In such cases, high-fiber foods may need to be temporarily limited as directed by a healthcare provider.
those with chronic IBS or SIBO
People with irritable bowel syndrome (IBS) or small intestinal bacterial overgrowth (SIBO) may not do well with more fiber. Including high-fiber foods may cause them to experience bloating, cramps, or digestive discomfort. 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. This refers to certain carbohydrates that may worsen symptoms in people with these gut disorders. Read more about the low FODMAP diet.
who are recovering from surgery
Doctors may recommend a low-fiber diet after certain types of surgery or medical procedures. Gastrointestinal surgery is a good example of this. Once you have fully recovered, it may be okay to add back high-fiber foods. Check with your doctor to know for sure.
How to include more fiber in your diet
Focus on eating whole foods to increase your fiber intake. You can also choose to use recipes with high fiber content. Here are some easy ways to get more fiber in your diet:
Soups and Stews
Add beans, lentils, chickpeas and peas to soups and stews. Or, focus only on recipes that already contain legumes. Here are a few ideas!
Beans are a reliable way to increase your fiber intake. You can always add a can or two to vegetable-based soups to increase fiber content.
eat raw vegetables with dip
For easy lunches or healthy snacking, bring a variety of raw vegetables. Then, pair them with fiber-rich hummus or guacamole. Try your crudettes with:
By combining raw vegetables with a fiber-rich dip, you’re doubling your efforts!
Enjoy nuts and seeds as a snack
Eat soaked or sprouted nuts and seeds for breakfast. Almonds, walnuts, pecans, sunflower seeds and pumpkin seeds are rich in fiber and delicious. Toasted and added to trail mix, they make a satisfying snack. Chia seeds are easy to incorporate into “pudding.” try these!
Nuts and seeds also appear as “flours” in grain-free pancakes and baking.
Try grain-free flour alternatives
Grain-free baking automatically utilizes high-fiber ingredients like nut flours, seed flours, 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 certain. Enjoy your fruits and vegetables in their whole, unprocessed form, and you’ll be surprised how easy (and delicious) it is to get high-fiber foods for you.
Do you try to eat a high-fiber diet? How do you intentionally include more fiber each day? Share with us below!