How often have you heard the advice, “Eat More Fiber”?
A simple suggestion that often raises several questions, such as: what is fiber, how much fiber do I need or how do I get more fiber, why do I need fiber?
Dietary fiber is found primarily in fruits, vegetables, whole grains, legumes, seeds and nuts.
It is the part of these plant foods, that is not digested nor absorbed as it passes through the human digestive system. Since it is not absorbed by the body, it does not provide any calories.
Fiber is divided into two types of fiber. Soluble fiber dissolves in water and forms a gel-like substance. It is found in oats, peas, beans, apples, citrus fruits, carrots, barley and psyllium. Fiber supplements such as Metamucil, Citrucel and Fibercon contain soluble fiber and will bulk up the stool and may aid in lowering cholesterol. But they do not contain the vitamins, minerals and phytochemicals that are present and beneficial, in high fiber foods.
Insoluble fiber absorbs water, making the stool bulk up and be softer, promoting the movement of material through the bowel. Insoluble fiber may be a benefit to those that suffer from constipation or irregular stools. Good sources of insoluble fiber include whole-wheat flour, wheat bran, nuts, beans and vegetables such as cauliflower, broccoli, green beans and potatoes to name a few.
A high fiber diet can:
Regulate bowel movements – By increasing the weight and bulk of your stool, dietary fiber makes the stool easier to pass, preventing constipation. If you have loose, watery stools, dietary fiber can attract the excess water, making the stool more formed.
Help maintain your bowel – The Mayo Clinic states that a high fiber diet may lower your risk of developing hemorrhoids and diverticular disease, the formation of small pouches in your colon, as well as lowering the risk of colorectal cancer.
Lower cholesterol levels – Soluble fiber from legumes, oats, oat bran, flaxseed and chia seeds may help lower total blood cholesterol levels. High fiber foods may also be beneficial in reducing blood pressure and inflammation.
Help control blood sugar levels – Soluble fiber can slow the absorption of sugar, so people with diabetes may have improved blood sugar control. A healthy diet high in insoluble fiber may reduce the risk of developing type 2 diabetes.
Aid in achieving healthy weight – High fiber foods, that are NOT high in fat, tend to provide less calories for the volume of food. A high fiber food usually takes longer to eat. High fiber foods are also more filling than low fiber foods so you may eat less food on a high fiber diet.
High fiber foods also maintain satiety longer. All of these factors aid in consuming less calories over all, that can result in gradual weight loss or at help to maintain your weight. Many studies suggest that a higher fiber diet, especially those with increased fiber from cereal fiber, may reduce your risk of cardiovascular disease and all cancers.
How much fiber you should consume daily is based on gender and age. The Dietary Reference Intakes (DRI) set by the Food and Nutrition Board, Institute of Medicine and National Academies, give the following recommendations for Adequate Intakes of fiber.
Age 50 or younger;
age 51 or older
Men: 38 grams; 30 grams
Women: 25 grams; 21 grams
There are many foods that are good sources of fiber that will increase your daily intake of fiber. The best sources of high fiber foods are from the following five groups of foods.
High Fiber Cereals – choose cereals that provide 4 or more grams of fiber/serving, for example oatmeal or cereals that have “whole grain,” “bran” or “fiber” in the name. Fiber One and All Bran provide the most fiber, about 15 gm/serving. You can also add some of these cereals to other cereals or add unprocessed wheat germ or oat bran to boost the fiber content.
Whole grain foods – when choosing grain products, such as bread, pasta, cookies, muffins, choose ones that list whole grain flours as the first ingredient and provide at least 2 grams fiber per serving. Use whole grain flours for half or all of the flour, when baking. Add crushed bran cereal, unprocessed wheat or oat bran, or uncooked oatmeal to muffins, cookies, cakes.
Choose fresh fruits, frozen or freeze-dried fruits as much as possible. Eat the skins when possible. The amount of fiber in fruits vary greatly depending on the fruit, but the average is 2-5 grams per cup or medium size fruit.
Fruits with the highest fiber content include avocado (10-15 gm/cup, pureed), raspberries (8 gm/cup), blueberries (15 gm/cup), pear (5.5 gm/medium pear), apple (4.5 gm/medium apple). Consume 2-4 servings of fruit per day. You can add fruit to your breakfast cereal, eat as a snack or dessert, put on waffles, pancakes, cakes, in muffins.
Choose fresh or frozen vegetables as much as possible. As with fruits, the amount of fiber in each vegetable varies greatly. On average vegetables provide 2-10 grams of fiber per serving. Higher fiber content vegetables include artichokes (10 gm/each), potatoes, sweet potatoes, Brussel sprouts (4 gm/ cup), winter squash, pumpkin, beets/carrots/peas (3-4 gm/cup). Canned vegetables and fruits have a lower fiber content. At your main meal try to have half your plate be vegetables and fruits. Try to eat 5 or more servings total of fruits and vegetables.
and other legumes
These foods have a great amount of fiber per serving, are high in protein and low in fat. One cup, cooked portion of the following legumes provide the amount of fiber listed.
Food/grams of fiber
Kidney beans 16.3
Split peas 16.3
Chick peas, canned 16.0
Black beans, canned 16.6
Baked beans 11-14
Add beans to soups, stews, casseroles, nachos, salads or puree for dips such as hummus to have with vegetables, crackers, chips, pretzels.
Nuts and seeds
These foods provide fiber, protein, but also contain a large amount of fat so they have more calories than other high fiber foods. They are considered “healthy” fats and as they are plant based, are cholesterol free. These foods can be added to baked goods, cereals, smoothies, yogurt or eaten as a snack.
Food/grams of fiber
Almonds, 1 cup 15.0-17.9
Sunflower seeds, roasted 1 cup 15.4
Pistachio nuts, roasted, 1 cup 12.7
Hazel, pecan, Brazil, macadamia nuts 1 cup 10.0-12.0
Walnuts, chopped 1 cup 7.8
Chia Seeds 1 tablespoon 4.0
Flaxseed 1 tablespoon 2.8
If you need to increase high fiber foods in your diet, do it gradually and be sure to drink plenty of water.
The recommended amount of fluid per day is eight, 8 ounce glasses per day. When adding fiber to your diet, you should also add more water, to prevent constipation and have adequate water for the increased fiber.
The Academy of Nutrition and Dietetics (AND) reports that a review and analysis of over 200 prospective studies and randomized controlled trials that investigated the relationship between carbohydrate quality and health was published in the medical journal The Lancet, in January 2019.
The research found that people that consume high amounts of dietary fiber, a daily intake of 25-29 grams, had significantly lower risks of heart disease, stroke, Type 2 diabetes, colorectal cancer and mortality.