When most people start trying to improve their nutrition, they immediately think about protein, calories, carbohydrates, fats and sugar.
Protein gets a lot of attention, and for good reason. If you want to maintain muscle, build strength and age well, getting enough protein is extremely important.
However, there is another part of nutrition that I believe gets overlooked far too often:
Fiber.
Fiber isn’t just about keeping you regular. In fact, it plays an important role in digestive health, blood sugar control, cholesterol, appetite, the gut microbiome and potentially even reducing the risk of certain diseases, including colorectal cancer.
Unfortunately, many people simply aren’t getting enough.
Fiber is a type of carbohydrate found primarily in plant foods that your body cannot completely digest.
Instead of being broken down and absorbed like most carbohydrates, much of it travels through the digestive system. Along the way, it can add bulk to stool, slow digestion or be fermented by bacteria living in the colon.
This is where things get interesting.
Certain fibers serve as food for intestinal bacteria. As those bacteria ferment fiber, they can produce compounds called short-chain fatty acids, including butyrate, acetate and propionate.
Researchers continue to study how these compounds may support intestinal and metabolic health.
Additionally, not all fiber behaves exactly the same way. That is one reason I recommend getting fiber from a variety of foods rather than relying on one source.
Fiber is commonly divided into two main categories.
Soluble fiber absorbs water and can form a gel-like substance in the digestive tract.
As a result, it may help:
Good sources include oats, barley, beans, lentils, peas, apples, berries, chia seeds, flaxseed and certain vegetables.
Insoluble fiber does not dissolve in water.
Instead, it adds bulk to stool and helps move material through the digestive system. Therefore, it can be especially helpful for maintaining bowel regularity.
Good sources include wheat bran, whole grains, brown rice, nuts, seeds, leafy vegetables and fruits and vegetables with edible skins.
There is another category worth understanding.
Certain fibers can be fermented by bacteria in the colon and may act as prebiotics. In simple terms, they provide food for beneficial gut microorganisms.
For example, prebiotic and fermentable fibers can be found in:
Because different fibers can affect the microbiome in different ways, eating a variety of plant foods is important.
Resistant starch is another interesting carbohydrate because it resists digestion in the small intestine and reaches the colon.
Good sources include beans, lentils, less-ripe bananas and some cooked-and-cooled potatoes, rice and pasta.
Like certain types of fiber, resistant starch can also be fermented by intestinal bacteria.
Ultimately, you do not need to obsess over which category of fiber you are eating.
Focus on eating a variety of whole plant foods, and you will naturally get several different types.
General daily fiber recommendations are:
| Group | Daily Fiber Goal |
|---|---|
| Men ages 19–50 | 38 grams |
| Men 51+ | 30 grams |
| Women ages 19–50 | 25 grams |
| Women 51+ | 21 grams |
| Pregnancy | 28 grams |
| Breastfeeding | 29 grams |
Another simple guideline is approximately 14 grams of fiber for every 1,000 calories consumed.
Additionally, the Daily Value listed on Nutrition Facts labels is 28 grams per day.
Many of the health benefits associated with fiber appear around approximately 25 to 30 grams per day, although individual needs can vary based on age, sex and calorie intake.
For most adults, I think a very practical goal is simple:
Start by consistently getting at least 25 to 30 grams per day and build from there based on your individual needs.
Low fiber intake can affect far more than your bathroom habits.
Fiber helps increase stool bulk. Depending on the type of fiber, it may also help retain water in the stool and make it easier to pass.
Therefore, a chronically low-fiber diet may contribute to harder stools and constipation.
Many bacteria living in your intestinal tract rely on fermentable carbohydrates and fiber for fuel.
When those fibers are fermented, gut bacteria can produce short-chain fatty acids that participate in intestinal and metabolic processes.
For that reason, gut health isn’t just about taking a probiotic.
You also have to feed the bacteria that are already there.
Certain soluble and viscous fibers slow digestion and glucose absorption.
As a result, they may help reduce rapid rises in blood sugar after meals.
Additionally, higher-fiber dietary patterns have been associated with a lower risk of developing type 2 diabetes.
Some types of soluble fiber can help reduce cholesterol.
For example, beta-glucan found in oats and barley and the soluble fiber found in psyllium have been studied for their cholesterol-lowering benefits.
More importantly, higher total fiber intake has consistently been associated with better cardiovascular health.
Fiber can slow digestion and increase feelings of fullness.
Consequently, it can be extremely useful when someone is trying to lose weight.
Foods such as vegetables, fruit, beans, lentils and whole grains provide food volume along with fiber. Therefore, rather than simply trying to eat less, improving the quality of the foods you eat can make controlling calories considerably easier.
This may be one of the most important reasons to pay attention to fiber.
However, we need to be careful about how we talk about it.
Eating a low-fiber diet does not mean someone will develop colon cancer. Likewise, eating plenty of fiber does not guarantee that someone won’t.
Cancer risk involves genetics, age, lifestyle, body weight, physical activity, alcohol, smoking, diet and many other factors.
Even so, substantial evidence has shown an association between higher fiber intake and lower colorectal cancer risk.
The World Cancer Research Fund reports strong evidence that foods containing dietary fiber decrease the risk of colorectal cancer.
In addition, a major systematic review and dose-response meta-analysis published in The BMJ looked at 25 prospective studies.
Researchers found that every additional 10 grams of total dietary fiber consumed per day was associated with approximately a 10% reduction in colorectal cancer risk.
Meanwhile, three additional daily servings of whole grains were associated with approximately a 17% lower risk.
More recent reviews have also continued to find an association between higher fiber intake and reduced colorectal cancer risk.
Researchers believe several mechanisms could be involved.
For example, fiber increases stool bulk and can reduce intestinal transit time. Fermentable fibers can also produce short-chain fatty acids such as butyrate, which continue to be studied for their role in maintaining a healthy colon environment.
Again, this doesn’t mean fiber is a cancer treatment.
Instead, it means a fiber-rich dietary pattern appears to be one important piece of a lifestyle associated with lower colorectal cancer risk.
You don’t have to eat enormous salads all day to get enough fiber.
For example:
| Food | Approximate Fiber |
|---|---|
| 1 cup cooked split peas | 16 g |
| 1 cup cooked lentils | 15.5 g |
| 1 cup black beans | 15 g |
| 1 cup green peas | 9 g |
| 1 cup raspberries | 8 g |
| 1 cup cooked whole-wheat pasta | 6 g |
| 1 cup cooked barley | 6 g |
| 1 medium pear | 5.5 g |
| 1 cup broccoli | 5 g |
| 1 medium apple with skin | 4.5 g |
Other great options include avocado, chia seeds, flaxseed, almonds, walnuts, oatmeal, quinoa, sweet potatoes, vegetables and whole-grain breads and cereals.
Getting enough fiber doesn’t have to be complicated.
Breakfast:
Oatmeal with berries and chia seeds
Lunch:
Chicken or another protein with vegetables and beans or lentils
Snack:
An apple or pear with a small serving of nuts
Dinner:
Lean protein with broccoli or another vegetable and a whole-grain carbohydrate
Together, those foods can easily put someone around or above 25 to 30 grams of fiber without dramatically changing everything they eat.
At Bodies By Design, we emphasize this kind of balanced approach to nutrition.
Good nutrition isn’t about eliminating every carbohydrate or living on chicken and protein shakes. Instead, we want our clients eating enough protein to maintain muscle while also consuming fruits, vegetables, legumes, whole grains and other foods that support their overall health.
Absolutely.
Ideally, most of your fiber should come from food because whole foods provide different types of fiber along with vitamins, minerals, antioxidants and other beneficial compounds.
However, supplementation can be helpful if someone consistently struggles to reach their daily target.
Common fiber supplements include:
Psyllium husk: A soluble, viscous fiber that can support bowel regularity and has evidence supporting cholesterol and blood sugar management.
Methylcellulose: Commonly used to help improve bowel regularity.
Inulin or chicory-root fiber: A fermentable fiber that can have prebiotic effects. However, it can also cause significant gas or bloating in some people.
Wheat dextrin and other isolated fibers: Convenient ways to increase daily intake, although different isolated fibers do not necessarily provide identical health benefits.
Most importantly, I would not use a fiber supplement as a replacement for a fiber-rich diet.
Think of supplementation as a way to fill a gap, not as an excuse to avoid fruits, vegetables, beans, whole grains and other fiber-rich foods.
This is where people sometimes run into problems.
If you’ve been eating very little fiber and suddenly start eating huge salads, beans, chia seeds and fiber supplements every day, your digestive system may not be ready for the sudden change.
As a result, you may experience:
Instead, increase fiber gradually and make sure you’re drinking adequate fluids.
Then give your digestive system time to adapt.
People with certain gastrointestinal diseases, a history of intestinal obstruction or other digestive conditions should speak with their healthcare provider before making significant changes to fiber intake or adding supplements.
Additionally, some fiber supplements can interfere with the absorption of certain medications.
When we’re talking about nutrition, protein matters.
Calories matter too.
Food quality matters.
Fiber deserves to be part of that conversation as well.
It helps support digestion, cholesterol, blood sugar regulation, appetite and the gut microbiome. In addition, higher-fiber dietary patterns are associated with lower risks of cardiovascular disease, type 2 diabetes and colorectal cancer.
You don’t need to make nutrition complicated.
Instead, take a look at what you’re eating throughout the day.
Are vegetables showing up regularly?
Are you eating fruit?
Could you add beans, lentils, whole grains, nuts or seeds?
Most importantly, are you consistently getting somewhere around 25 to 30 grams or more of fiber each day?
For many people, improving this one area of nutrition could make a meaningful difference in their long-term health.
The goal isn’t to chase perfection or completely overhaul your diet overnight. Rather, start paying attention to something that often gets ignored. Add another serving of vegetables. Include some fruit. Experiment with beans or lentils. Choose more whole grains. Then gradually build those habits into your normal routine.
At Bodies By Design, we believe some of the biggest improvements in health come from doing the basic things well and doing them consistently.
Fiber may not be the most exciting part of nutrition, but it is absolutely one of the most important.
Small improvements in what you eat today can have a major impact on how you feel, function and age tomorrow.
Committed to your overall health,
This article is intended for general educational purposes and is not a substitute for individualized medical or nutrition advice.