Fiber, Sugar & Carbohydrates - How Do They Relate to Each Other?
Last updated: March 2022
What is fiber and why is it a carbohydrate? Does it count as a calorie? Many people don’t know what fiber is or what it does. They often wonder why it’s grouped with carbohydrates and if it really is a part of the total amount of grams that make up carbohydrates. Questions arise such as “Should I be watching my fiber intake along with watching my sugar intake?” and “What is the relationship between sugar and fiber?” We’ll teach you about what fiber is, what it does, and how it relates to sugar and total grams of carbohydrates on the nutrition facts label.
What are carbohydrates?
Carbohydrates (aka carbs) are one of the main types of nutrients; the other two are protein and fat. Carbohydrates are the easiest used form of energy for your body. When you digest carbs, your digestive system breaks them down to blood sugars (glucose) that your cells and tissues can easily take up for energy. Extra blood sugars that aren’t immediately used by the body are converted by your liver into stored sugars (glycogen) that are retained in your liver and muscles.
What are the three types of carbohydrates?
Carbohydrates come in a variety of forms. The three most common and abundant forms are sugars (simple carbohydrates), starches (complex carbohydrates), and fiber (complex carbohydrates). When you read the total amount of carbohydrates on a nutrition label, all three forms are included.
- Sugars are simple carbohydrates. Simple carbs can be split into natural sugars found in fruits or milk products or added sugars, which are added during processing or baking.
- Starches are complex carbohydrates made up of many simple sugars linked together and are broken down in the body. Starches are found in certain vegetables as well as certain breads, cereals, and other grains.
- Fiber is a complex carbohydrate composed of sugar molecules held together by bonds that humans cannot break down. Since the body cannot break these specific bonds, you do not take in any energy when eating fibers. This affects how long it takes to digest fiber-rich foods, thus resulting in an increased feeling of fullness and satiety. In addition, fiber slows down the digestion of other nutrients, including sugars and starches, and helps prevent large blood glucose and insulin spikes.
What is soluble and insoluble fiber?
There are two types of fiber: soluble and insoluble. Although neither soluble nor insoluble fiber can be absorbed by the body, the two types of fiber react differently when mixed with water.
- Soluble fiber attracts water and turns into a gel-like substance when digested, which helps make you feel full. Soluble fiber has many benefits, including stabilizing blood glucose levels and lowering cholesterol. Pectins, gums, mucilages, and some hemicelluloses are types of soluble fiber. Good sources of soluble fiber include oats and oatmeal, legumes (peas, beans, lentils), barley, fruits, and vegetables.
- Insoluble fiber does not absorb or dissolve in water. It passes through our digestive system in close to its original form and keeps us “moving!” Insoluble fiber offers many benefits to intestinal health, including a reduction in the risk and occurrence of hemorrhoids and constipation. The scientific names for insoluble fibers include cellulose, lignins, and also some other hemicelluloses. Most insoluble fibers come from the bran layers of cereal grains.
Moderate evidence shows that adults who eat more whole grains, particularly those higher in dietary fiber, have a lower body weight compared to adults who eat fewer whole grains.1
Recommended daily fiber
Most Americans fall short of the recommended amount of daily dietary fiber, consuming an average of only 12 to 17 grams per day. Current recommendations suggest that children and adults consume at least 20 grams of dietary fiber per day from food, not supplements. The more calories you eat each day, the more fiber you need; teens and men may require upwards of 30 to 35 grams per day or more.2
According to the 2010 Dietary Guidelines for Americans, women should aim for 25 grams of fiber a day and men should aim for 38 grams a day.
Ways to get more fiber
To hit these numbers, try some of the following changes:
- Eat your daily goal of 5 vegetables and 4 servings of fruit each day.
- Try Meatless Monday and replace meat products with beans and lentils.
- Substitute a portion of whole wheat flour for white flour in your favorite recipe. Or give oat flour a try, like in these delicious oat flour waffles.
- Add bran or wheat germ to your baked goods or smoothies for a boost of fiber.
- Choose brown or wild rice and whole-grain pastas instead of the white or refined versions of the same grains. Don’t love the flavor of the whole grain versions? Start by using 1/4 whole grain and 3/4 white and slowly reverse the proportions.
- Read food labels. In order for food to be labeled “high fiber,” it must contain at least 5 grams of fiber per serving.3
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