Fact checked by Aimee McNew for Accuracy
Fiber is an important component of carbohydrates that few Americans actually get enough of.
While we, as a whole, consume more than enough carbohydrates (and typically far too much), the average intake of fiber is dramatically low. In fact, only five percent of Americans actually get enough.
The low level of fiber in the average American diet has been deemed a public health concern. (1)
Why is fiber so important?
This article explores what it is, proven health benefits, how to get enough, and what foods exactly you need to eat to get your daily fiber intake.
What is Fiber?
Fiber is an indigestible component of carbohydrates in plant foods like fruits, vegetables, beans, and grains. It is one of the major reasons why these foods are healthy, and every human needs fiber for many reasons.
Some of the key benefits of fiber include:
- Roughage to promote proper digestive function
- Slows carb digestion and promotes good glucose levels
- Keeps you feeling full
Most people know that fiber is healthy, but don’t necessarily know why or how much they’re actually eating. Surveys find that people tend to think they’re getting more than they really are.
Types of Fiber
While all fiber is good for you and has important health benefits, there are two different types. Each is required in its own right for wellbeing.
Soluble fiber is a type of fiber that is fermentable and can dissolve in water. The beneficial bacteria in the gut use this fermentation process to grow and proliferate.
This type of fiber promotes healthy immunity since the gut is a major regulator of the immune system.
Insoluble fiber does not ferment and cannot be dissolved in water. It functions as roughage in the digestive tract to help promote digestive motility.
That’s basically a fancy way of saying it keeps the intestines and bowels moving, preventing constipation and being stopped up.
5 Health Benefits of Fiber
Fiber has many health benefits. These are the most research-proven and medically backed reasons to include fiber in your diet.
1. Helps Blood Sugar Levels Stay Steady
Blood sugar, also known as glucose, is what carbohydrates get converted to after they digest. When you eat carbs that are low in fiber, you get a bigger jolt of sugar that enters the bloodstream.
Fiber is an indigestible part of carbs that helps to slow the release of glucose into the bloodstream, providing a more stabilizing effect on blood sugar levels.
People who are diabetic are familiar with measuring things on a glycemic index scale, or by measuring foods according to “net carbs.” Foods with lots of fiber have a lower glycemic index, making them more diabetes-friendly. Foods with more fiber also have fewer net carbs.
Eating more carbohydrates that are higher in fiber can help to prevent blood sugar spikes and can help address and prevent diabetes. (3)
2. Promotes Good Gut Health by Helping Good Bacteria Thrive
The human gut is home to trillions of bacteria, some good and some bad. Literally the bacteria in the gut outnumber our other cells in a ratio of 10 to 1. Without this host of bacteria, humans wouldn’t actually exist.
More than 500 different species of bacteria are in the gut, and supporting diversity is the key to ensuring good gut health and overall balance. When a few dominant “bad” strains take over, the result can be major digestive woes and discomfort, not to mention health issues.
While we can’t digest fiber in and of itself, soluble fiber has an important role in nourishing the good bacteria in the gut. (7)
The good bacteria thrive in the presence of this fiber, and also produce short-chain fatty acids which have health benefits of their own (like reducing the risk of heart disease, cancer, and diabetes). (8)
Many people avoid eating high-fiber foods because they can cause bloating and gas, especially in people who don’t eat them frequently. But this gas-producing quality is also what allows the good gut bacteria to feed off of it.
While some people have sensitivities to fermentable fiber foods, like beans and legumes, others would notice a decrease in bloating and gas if they made it a point to eat a higher fiber diet on a consistent basis.
Digestive enzymes can also help.
3. May Protect the Colon from Cancer
Cancer of the colon is the third most deadly cancer in the world. (9) While every cancer is different, the risk of colon cancer specifically can be reduced by a higher intake of fiber-rich foods like fruits, vegetables, whole grains, beans, and legumes. (10)
How much fiber you need to see a protective effect hasn’t been fully determined, but meeting daily requirements would be a start. Most people only get about half of the fiber that they need each day.
4. Helps Address and Prevent Constipation
Constipation is a common problem in the developed world because of the higher consumption of processed foods, protein, and fat. Fiber can help to reduce constipation and promote a healthy digestive tract—and that includes elimination.
There are many types of fiber, by psyllium fiber is the most effective at reducing constipation-related problems. This is because it forms a gel-like substance at it works its way through the digestive tract, essentially sweeping out waste that may have “clogged” the system. (13)
Prunes, another popular constipation remedy, work their magic because they too are rich in fiber. This type helps increase the amount of water in the bowels and colon, helping to promote elimination by releasing waste that has become too dried-out to effectively move through the colon. (14)
Fiber from food sources can be exceptionally effective at addressing constipation. However, the temptation to take laxatives for a quick fix can be strong.
Laxatives can damage muscle tone in the intestines, actually worsening the long-term nature of constipation problems. They can also have other negative side effects, like dehydration.
5. Keeps You Feeling Full (and Promotes Weight Loss)
One of the biggest challenges when it comes to losing weight is the constant feeling of hunger.
While extreme calorie-restricted diets are not a good way to lose weight because they also restrict nutrients your body needs to thrive, there is a way to not feel hungry all the time.
Eating fiber-rich foods can promote feelings of fullness and lead to weight loss. If you’re not hungry all the time, you will eat less, which could result in natural weight loss.
Not only can it increase feelings of fullness, but it also helps to promote balanced blood sugar. For people with metabolic imbalances or type 2 diabetes, this is an important avenue to weight loss and better health.
25 Foods Highest in Fiber
Many foods have some amount of fiber in them. But if you want to dramatically increase the fiber in your diet, focusing on high-fiber foods is the best way to do it.
With this list, you will have plenty of variety and new foods to work in each day to boost your fiber intake.
These are the 25 foods highest in fiber, ranked from most to least per serving:
- Oats (16.5 grams per cup)
- Split peas (16 grams per cup)
- Lentils (15.5 grams per cup)
- Black beans (15 grams per cup)
- Chickpeas (12.5 grams per cup)
- Kidney beans (11 grams per cup)
- Chia seeds (10.5 grams per ounce)
- Avocado (10 grams per cup)
- Artichoke (10 grams each)
- Raspberries (8 grams per cup)
- Pears (5.5 grams in a single fruit)
- Quinoa (5 grams per cup)
- Pumpkin seeds (5 grams per ounce)
- Apples (4.5 grams in a single fruit)
- Brussels sprouts (4 grams per cup)
- Red beets (4 grams per cup)
- Sweet potatoes (4 grams each)
- Carrots (3.5 grams per cup)
- Almonds (3.5 grams per ounce)
- Blueberries (3.5 grams per cup)
- Bananas (3 grams per fruit)
- Broccoli (2.5 grams per cup)
- Kale (2.5 grams per cup)
- Spinach (2.5 grams per cup)
- Walnuts (2 grams per ounce)
How to Increase Your Fiber Intake Naturally
If you want to eat more fiber in your diet, it’s simple. Choose some higher-fiber foods from the list above and start adding them to your meals more often. You don’t have to dramatically change the way you eat to get the benefit of more fiber.
Simply add a serving of fruit with your breakfast, and add an extra vegetable or fruit to lunch. Start using high-fiber sides like quinoa or beans instead of white rice or white potatoes with meals, and you’ll be hitting your daily fiber needs before you know it.
If you’re not used to eating a high fiber diet, be sure to make these changes slowly. You won’t want to suddenly eat all high-fiber foods. Instead, gradually make these changes over the course of two or three weeks.
If you experience bloating or gas or other symptoms of discomfort and they don’t subside within a few days, check in with your doctor.
These are the top simple ways to naturally work more fiber into your food plan:
- Eat fruit instead of drinking juice
- Swap sweet potatoes for white potatoes
- Swap quinoa for brown or white rice
- Eat chia pudding or oatmeal for breakfast instead of cereal
- Eat almonds instead of peanuts
- Add beans to your soups and stews
- Add more vegetables and fruits to each meal
Should You Try Fiber Supplements?
If you make dietary changes and you still struggle to get in enough grams of fiber, should you try fiber supplements?
The important thing to know about fiber supplements is that they don’t replace a diet high in fiber. Just taking a supplement alone isn’t enough.
Secondly, some supplements can contain other ingredients or fillers that people can be sensitive to. Always read the labels.
If you do choose to try a fiber supplement or your doctor has recommended one, always be sure to start slowly. If you go from nothing to a full dose, you will likely experience extreme bloating and intestinal discomfort.
Most fiber supplements also require being taken with water to avoid leading to constipation or other symptoms.
Cautions About Dietary Fiber
While fiber has numerous health benefits, there are some cases where consuming lots of fiber can actually cause health issues.
Particularly in Crohn’s disease or IBD (irritable bowel disorder), too much fiber can lead to intestinal blockage and can cause other more serious problems.
If you have any health conditions, always speak to your doctor before making dramatic dietary changes or before starting any supplements.
How Much Fiber Do You Need Every Day?
Men and women have different fiber needs. Guidelines say that men need 38 grams per day, while women need 25 grams. Some experts say these recommendations only make up about half of what we need to truly be healthy.
Fiber has many health benefits and most adults aren’t getting enough. Different types of fiber work to promote good gut health, protect against certain types of cancer, and even promote feelings of fullness.
Without fiber in the diet, the digestive system becomes inefficient and weakened.
Eating a diet that contains enough fiber, from varying sources, is a simple and essential way to promote good health all around. Focus on whole foods fiber sources, but when necessary, fiber supplements can help to promote balance, too.
Always be sure to check with your doctor before making dietary changes or starting new supplements.
This article was fact checked for accuracy by Aimee McNew, MNT, a certified nutritionist. As always, this is not personal medical advice and we recommend that you talk with your doctor.
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- Tucker L.A., Thomas K.S. Increasing total fiber intake reduces risk of weight and fat gains in women. J. Nutr. 2009;139:576–581.
- FDA, authors. Code of Federal Regulations. Vol. 2 Food and Drug Administration; Silver Spring, MD, USA: 2008. Health claims: Fiber-contaning grain products, fruits and vegetables and cancer.
- Story J.A., Furumoto E.J., Buhman K.K. Dietary fiber and bile acid metabolism—an update. Adv. Exp. Med. Biol. 1997;427:259–266.
Aimee McNew, MNT, CNTP, is a certified nutritionist who specializes in women’s health, thyroid problems, infertility, and digestive wellness. She ate her way back to health using a Paleo diet, lost 80 pounds, and had a healthy baby after numerous miscarriages. She focuses on simple nutrition practices that promote long-lasting results.