What is Fiber? What is high in fiber?
Fiber is made up of non-starch polysaccharides, such as cellulose, dextrins, inulin, lignin, chitins, pectins, beta-glucans, waxes and oligosaccharides. The word fiber is misleading, because many types of dietary fibers are not fibers at all.
There are two broad types of fiber, soluble and insoluble.
- Soluble fiber dissolves in water. It changes as it goes through the digestive tract, where it is fermented by bacteria. As it absorbs water it becomes gelatinous.
- Insoluble fiber does not dissolve in water. As it goes through the digestive tract it does not change its form.
Dietary fiber foods are generally divided into predominantly soluble or insoluble.
Both types of fiber are present in all plant foods, but rarely in equal proportions.
Fruits and Vegetables
- Apples, bananas, oranges, strawberries all have around 3 to 4 grams of fiber. (Eat the apple peels -- that’s where the most fiber is!)
- Raspberries win the fiber race at 8 grams per cup.
- Exotic fruits are also good sources of fiber: A mango has 5 grams, a persimmon has 6, and 1 cup of guava has about 9.
- Dark-colored vegetables. In general, the darker the color of the vegetable, the higher the fiber content. Carrots, beets, and broccoli are fiber-rich. Collard greens and Swiss chard have 4 grams of fiber per cup. Spinach also packs a punch at 7 grams of fiber per half-cup. Artichokes are among the highest-fiber veggies, at 10 grams for a medium-sized one.
- Potatoes. Russet, red, and sweet potatoes all have at least 3 grams of fiber in a medium-sized spud, if you eat the skin and all.
Dry and Canned Goods
- Stock up on beans. Navy and white beans are the most fiber-rich, but all beans are fiber-packed. Any of these is a good choice for your shopping cart: garbanzo, kidney, lima, or pinto beans. They make great soups and chilis, and are a flavorful addition to salads. Beans are also high in protein, so if you’re cutting back on red meat, they’re a healthy, filling substitute.
- Include other legumes. Peas, soybeans (edamame), and lentils are also high in fiber.
Bread and Grains
- Check cereal labels. Most cereals have at least some fiber content, but they’re not all created equal. Any cereal with 5 or more grams of fiber per serving is a good source.
- Whole-grain breads. Seven-grain, dark rye, cracked wheat, and pumpernickel breads are good choices.
- Whole grains. Bulgur wheat, brown rice, wild rice, and barley are all tasty substitutions for white rice.
The Snack Aisle
- Nuts and seeds. A handful of sunflower seeds, pumpkin seeds, pistachios, or almonds gives you at least 3 grams of fiber. They are also high in calories, though, so make a little go a long way.
- Popcorn. Three cups of air-popped popcorn have about 4 grams of fiber.