The USDA recommends that healthy adults consume 14 grams of fiber for every 1,000 calories consumed. Because most adults consume about 2,000 calories daily, they need roughly 28 grams of fiber. Meeting this recommendation can be challenging if you are eating a lot of processed foods with empty calories, but by increasing your intake of plant-based foods, you can meet these recommendations and keep your body healthy.
Types and Functions of Dietary Fiber
Dietary fiber consists of two types: insoluble and soluble. Insoluble fiber is not digested or absorbed by the body, and it basically passes through the gastrointestinal tract intact, which promotes regularity and prevents constipation. Soluble fiber is also not digested; rather, it dissolves in the gastrointestinal tract and becomes a gel-like substance that helps prevent absorption of cholesterol and regulates blood sugar. Both types of fiber contribute to satiety, or feelings of fullness, after consuming a meal, so high-fiber diets are typically recommended for those individuals trying to lose weight.
Plant-based whole grains are an excellent source of dietary fiber for adults. The grain itself contains three parts: the endosperm, the bran and the germ. While the germ and the endosperm contain essential oils and B-complex vitamins, the bran houses most of the fiber. Brown rice, quinoa, oats, bulgur and barley are all examples of whole grains, and each half-cup serving of these grains contains at least 3 grams of fiber.
Fruits and Vegetables
Whether raw, steamed or cooked, fruits and vegetables also contribute significantly to the fiber content in a healthy diet. Fruits with skins or heavy pulp such as apples, pears, berries and plums tend to have 4 to 5 grams of fiber per serving. Turnips, okra, asparagus and Brussels sprouts are examples of high-fiber vegetables that contain 3 to 4 grams of fiber per serving. Fruit and vegetable juices may also contain some fiber, but more fiber is obtained when you eat the entire fresh fruit or vegetable.
Many foods on the shelves at the grocery store have additional fiber added to them in order to improve their nutritional value. High-fiber granola bars, breads, tortillas and bagels are readily available at most major grocery chains, and each serving of these foods has anywhere from 9 to 13 grams of fiber per serving. Before purchasing these foods, compare their nutrition labels for fiber content and select the one with the highest amount. You can also read the ingredients labels and look for foods with added fiber from ingredients such as inulin and chicory root.
Gluten-Free Sources of Fiber
If you suffer from celiac disease or gluten intolerance, you may not be sure how to meet your daily fiber needs. However, whole grains such as quinoa, millet, corn and wild rice are all gluten-free and appropriate for those individuals following a gluten-free diet. In addition, legumes such as black, kidney, garbanzo and pinto beans do not contain gluten, and these foods have at least 5 grams of fiber per serving.
- The Whole Grains Council: What is a Whole Grain?
- Syracuse University: Inulin, the New Fiber, is Showing Up in Juices, Yogurts and Other Foods
- The Whole Grains Council: Gluten Free Whole Grains
- Tufts University: Fiber
- Harvard School of Public Health: Fiber Content of Foods in Common Portions
- MayoClinic.com: Dietary Fiber: Essential for a Healthy Diet
Dr. Courtney Winston is a registered/licensed dietitian, certified diabetes educator and public health educator. She holds a Master of Public Health from the University of North Carolina at Chapel Hill and her doctoral degree from the University of Texas Health Science Center. Dr. Winston was recognized in 2012 with the Academy of Nutrition and Dietetics Emerging Leader in Dietetics Award for the state of California.