Fiber can lower blood sugar, cut cholesterol, and may even prevent colon cancer and help you avoid hemorrhoids. If it were a drug, the world would be clamoring for it. But few people are getting enough. Women should get about 25 grams a day and men at least 35 to 40, but the average person gets just 15 grams a day. Eating fiber-rich whole foods—not foods that tout "added fiber"—is the best way to increase your fiber intake, says Carolyn Brown, RD, a nutritionist at Foodtrainers, in New York City. Here is a list of high-fiber foods that should be included in the diet:
Corn
We're most familiar with the sunny, yellow version, but corn comes in a rainbow of colors—from pink to blue to black—each with its own special combination of antioxidant nutrients. A single ear of corn, which is about a half cup of corn kernels, contains 2 grams of fiber. Popcorn is also a terrific—and low-calorie—fiber source, with about 3.5 grams of fiber per three-cup serving.
White beans
In addition to being rich in fiber, protein, and iron, white beans are one of the best nutritional sources of potassium—1 cup will cover 25% of your daily requirement for this hypertension-fighting nutrient. Beans get a bad rap when it comes to gas, but the key is to amp up your fiber intake gradually, Brown says. "If you only eat (low-fiber) foods right now, don't suddenly switch to eating 40 grams of fiber a day, because that will cause a lot of stress to the digestive system."
Black beans
Black beans contain 15 grams of fiber per cup, and about 15 grams of protein. Their dark, rich color signals a high content of flavonoids, plant pigments that are powerful antioxidants. As you add beans and other high-fiber foods to your diet, be sure to drink more water, too, Brown says.
Kidney beans
The key ingredient in red beans and rice, kidney beans are popular in northern India as well as New Orleans. Like their cousins—pretty much all of the beans we eat share the Latin name Phaseolus vulgaris, or "common bean"—they're rich in fiber, protein, and iron.
Avocado
The creamy flesh of the avocado is a great fiber source; a two-tablespoon serving of avocado has about 2 grams of fiber and an entire fruit contains around 10 grams. Avocados are also an excellent source of mono- and polyunsaturated fats—the "good" kind that can help lower cholesterol and reduce heart-disease risk.
Brown rice
If you've been strictly a white-rice eater, the chewier texture and nuttier taste of brown rice can take some getting used to—but it's worth the effort. Every cup contains 3.5 grams of fiber. Harvard researchers recently found that although eating five or more servings of white rice a week increased type 2 diabetes risk by 17%, adding a couple servings of brown rice per week decreased risk by 11%.
Lentils
This tiny member of the legume family is super-rich in fiber, with 15.6 grams per cup. Cultivated since Neolithic times, lentils are also a great source of protein, B vitamins, iron, and other minerals.
Along with fiber and adequate fluid intakes, fiber is responsible for quickly moving foods through the digestive tract, helping it function optimally. Fiber works by drawing fluids from the body to add bulk to the stool. When increasing dietary fiber in your diet it is essential to start slowly, and increase gradually.