According to data curated by the Department of Agriculture, only about 5% of Americans consume their daily recommended allowance of fiber. And that’s unfortunate, because fiber plays a big role in many aspects of health.
“Fiber has multiple health benefits,” says Dr. Elizabeth Klodas, a cardiologist based in Minneapolis and founder and chief medical officer of Step One Foods, a food products company that helps users manage cholesterol levels through diet.
Health Benefits of Fiber
Benefits of getting enough fiber in your diet include:
- Improving bowel regularity. A low-fiber diet can lead to constipation, which can become chronic. Eating enough fiber on a regular basis promotes bowel regularity.
- Keeping blood glucose levels stable. A meal that’s high in fiber will slow down digestion of food, which slows the related rise in blood sugar. Especially if you’re eating a meal that’s high in simple carbohydrates like sugar, adding a food that’s high in fiber reduces the chances of a blood sugar spike and subsequent crash as that food breaks down in your body. Controlling blood sugar level is especially important for people with prediabetes or diabetes.
- Increasing satiety. Because fiber slows down digestion of food, that can help you feel fuller longer, which is great if you’re trying to manage your weight.
- Lowering risk of heart disease. A high-fiber diet is associated with improved blood lipid levels. Soluble fiber helps lower LDL (or low-density lipoprotein, the so-called ‘bad’ type of cholesterol), which reduces the risk of heart disease.
- Aiding in nutrient intake. Many foods with fiber aren’t just beneficial because they’re fibrous; they’re also good inclusions for your diet because they contain a variety of other necessary vitamins and minerals that can also support good health.
- Supporting a healthy gut biome. Science is learning more about the plethora of good bacteria that live inside the gut to help digest food and offer health benefits to the rest of the body. A high-fiber diet helps those gut flora to thrive.
- Lowering risk of certain kinds of cancer. A diet high in fiber has been shown to reduce risk of several kinds of cancer, including colorectal and breast cancer. Kailey Proctor, a board-certified oncology dietitian at the Leonard Cancer Institute at Providence Mission Hospital in Mission Viejo, California, explains that “fiber binds with estrogen in the digestive track to remove excess estrogen in the body. Estrogen is a hormone that helps with breast cell growth, and research shows that prolonged exposure to high levels of estrogen may increase the risk of breast cancer in women. Fiber also helps women maintain a healthy body weight, because it acts like a balloon in the stomach to keep you fuller longer between meals so you’re less likely to snack on high calorie foods that may lead to weight gain.” And as the Centers for Disease Control and Prevention reports, being overweight or having obesity increases your risk for 13 types of cancer.
But What Exactly Is Fiber?
Quite simply, fiber is a natural component of plant-based foods. “Many people equate fiber with roughage, which it is,” Klodas says. But it’s also “a type of carbohydrate that you can’t digest or absorb.” And you can’t get fiber from protein or fat. “It’s part of carbohydrates,” she explains.
“All carbohydrates are absorbed as sugar. So if you don’t have fiber along for the ride, you’re going to digest and absorb that carbohydrate very quickly and your blood sugar levels are going to spike, which means that your insulin levels are going to spike and that sets off a whole host of counterproductive biochemical pathways,” Klodas explains.
There are actually two types of fiber:
- Soluble fiber dissolves in water and slows down digestion. It can also help lower your “bad” cholesterol levels and regulate blood glucose levels. Apples, beans, Brussels sprouts, avocado, pears and lentils are just a few foods that are high in soluble fiber.
- Insoluble fiber does not dissolve in water; rather, it pulls water into the colon to produce softer stools. Insoluble fiber bulks up the stool, which can help food waste pass more efficiently through the body. It can also help promote bowel regularity. Whole grains, oat bran, vegetables, beans, nuts and legumes are all good sources of insoluble fiber.
It’s important to get a balance of both types of fiber.
How Much Is Enough Fiber?
Emily Rice, a registered dietitian with the Ohio State University Wexner Medical Center in Columbus, says that “women need 25 grams per day and men need 38 grams per day.” Or, “another way to look at fiber intake is getting 14 grams per 1,000 calories you’re eating.”
The USDA also recommends that everyone consume 14 grams of fiber per 1,000 calories of food. On average, adults are recommended to consume 2,000 calories per day, so if you’re consuming 2,000 calories per day, you’d need to consume 28 grams of fiber per day. If you eat more or fewer calories each day, you can adjust your fiber intake accordingly.
Increasing Your Fiber Intake
While the recommended amount of fiber you should be consuming is clear, “many Americans eat less than 50% of their daily fiber needs,” Rice says. Overly-processed foods tend to be very low in fiber, and the standard American diet typically includes many of these fiber-poor items.
If you’re not currently meeting your daily recommended allowance of fiber, it’s wise to consider boosting your intake by adding more high-fiber foods to your diet. That means adding more plant-based foods including:
- Legumes. Beans, peas and lentils are all part of the legume family. These starchy plants contain a lot of fiber and are good source of protein. Add them to your plate for plenty of nutrition.
- Whole grains. Whole grains are grains that have not been refined, meaning that it contains all three parts of the kernel. There’s lots of fiber in those outer layers of the grain, as well as B vitamins and other nutrients. Reach for 100% whole-wheat breads and pastas, brown rice, bran cereals, rolled oats or oatmeal and popcorn.
- Fruits. Fruit, especially if you eat it with the skin on, is very high in fiber. Top choices include raspberries, pears, blueberries, strawberries, bananas, apples, peaches and prunes.
- Vegetables. High-fiber vegetables include broccoli, cauliflower, carrots, spinach, potatoes, sweet potatoes, string beans and peas.
- Nuts and seeds. Nuts and seeds of all types can provide a boost to both your fiber and protein intake. Chia seeds, flax seeds, pumpkin seeds, almonds, pistachios, pine nuts and chestnuts are all good sources of fiber. In addition to fiber, nuts and seeds are also good plant-based sources of omega-3 fatty acids, which have heart-protective effects, and their high fat content can help you feel fuller longer.
Animal products don’t naturally contain fiber, but you may notice some food labels for animal-based products list fiber. This means it’s been added during processing. Fiber that comes from whole, plant-based foods is considered the better option because it’s naturally occurring.
Klodas notes that some diets, such as the ketogenic diet, are low in fiber and may not be a good choice if you need to reduce your cholesterol levels. “The keto diet, which is very high in fat and protein, and high-protein diets in general, tend to be carbohydrate-restricted. On these diets you end up, almost on purpose, consuming very little fiber,” she says.
Quick Tips for Boosting Fiber
Here are some easy tips for increasing fiber in your diet:
- Consume whole fruit rather than fruit juice. When fruit is juiced, that removes the skin and pulp, which is where the fiber is. Eating a whole apple instead of drinking a glass of apple juice is the better option.
- Instead of peeling endlessly, incorporate the skin into mashed potatoes. It’s delicious and adds a big fiber punch.
- If you like sugary cereal in the morning, you don’t have to give it up cold turkey. Instead, mix in a high-fiber cereal and gradually transition to a ratio of less sugar cereal to more high-fiber cereal.
- Try new grains, such as quinoa, barley, rolled oats and farro.
- Replace all-purpose flour with whole-grain flour in some recipes.
- Make your own trail mix with a high-fiber cereal, nuts and dried fruit.
- Look for breads and cereals with “whole wheat” or “whole grain” listed as the first ingredient.
- Mix flaxseeds into baked goods or sprinkle on toast, salads and other dishes.
- Add cooked beans into soups or pureed into dips. You can even add mashed black beans to brownies to sneak some extra fiber into a delicious package.
- Choose high-fiber fruits and veggies, popcorn, whole-grain crackers or nuts for snacks.
Fiber Supplement Considerations
Rice says that it’s best to get your fiber from whole food sources first before adding a supplement.
Klodas agrees. “There’s something magical about a blueberry. When a blueberry enters the body, our cells know what to do with that and they know how to get the vitamins and fiber from them and so forth,” in a more efficient way than if you took a vitamin C or fiber supplement.
You also get other nutrients. “One of the reasons why eating whole foods that supply fiber is superior is because you get so much more than the fiber,” Klodas says.” You get unbelievable mixtures of micronutrients and vitamins and phytochemicals and all these things that the body needs. Fiber is one thing, but it’s not the only thing.”
Even so, Rice notes that “if you’re not able to achieve your fiber goals through food, a fiber supplement could be a good addition.” There are many fiber supplements on the market, but Rice cautions that “they can impact absorption of some medications,” and thus may not be recommended for use by some people with certain conditions.
For example, if you’re taking the diabetes medication metformin, it’s best to avoid taking a fiber supplement at the same time. Take your medications two to three hours before or after you take a fiber supplement to avoid having the medications being swept out of the digestive tract before they can be absorbed fully.
In any event, Rice recommends discussing all supplements you might be considering taking with your provider before use.
Increase Your Fiber Intake Slowly
Lastly, if you don’t consume enough fiber currently, be sure to increase your intake slowly. Suddenly increasing fiber intake and taking in “too much all at once can overwhelm the gastrointestinal tract, leading to abdominal distension, bloating, cramping, nausea and potentially diarrhea or constipation,” Rice says.
And be sure to “drink plenty of water while increasing fiber to decrease likelihood of constipation,” she adds.