Carbohydrates often get clumped together in two extreme categories: good and bad. However, carbs alone aren't bad. Everyone needs them because carbs are the body's primary source of energy. The three types of carbs -- sugar, starch and fiber -- all have a place in your diet. Even sugar is a good carb as long as the type of food from which you obtain it is healthy.
The three carbohydrates -- sugar, starch and fiber -- are all made from molecules of sugar. However, sugar also refers to a type of carbohydrate. Sugars, or simple carbohydrates, contain just one or two molecules of sugar. The complex carbohydrates -- starch and fiber -- consist of many molecules of sugar. In fact, they can contain thousands of sugar molecules connected to form spiral and branching shapes, notes the Oregon State University website When sugars and starches are digested, enzymes break them down until only single molecule of sugar, or monosaccharide, remains. Monosaccharides are the only form of sugar that can enter your bloodstream and subsequently into your cells, which convert them into energy.
Sugar for Energy
Some of the most familiar sugars include glucose, fructose, sucrose and lactose. Glucose is better known as blood sugar, but like fructose and sucrose it's also a natural sugar found in fruits and vegetables. Lactose is the natural sugar in milk. Sugars gain rapid access to your bloodstream because they have so few sugar molecules to digest. When you obtain natural sugar from whole foods, you gain the energy boost together with vital nutrients. Added sugars, in contrast, contribute calories for energy but don't have other redeeming qualities. They lack nutrients, cause unhealthy spikes in blood sugar and promote weight gain, notes the American Heart Association.
Types of Starches
Different types of starches are digested at varying rates. Some are slowly digested, giving you long-term energy and helping you feel full. Other starches digest rapidly and can spike blood sugar. The third type, called resistant starch, isn't digested; it’s fermented in the large intestine. Many foods with starch contain all three types of carbohydrates and aren't easily labeled as sources of a specific one, according to an article in the March 2011 issue of “Nutrients.” Starchy foods, such as peas, corn, beans, pasta, rice, potatoes and grains, deliver essential vitamins and minerals. Peas and beans are also good sources of protein and fiber. Avoid refined grains and go with whole grains because only whole grains retain all of the beneficial fiber.
Fiber and Its Health Benefits
When you consume fiber, most of it goes through your digestive tract without being digested, but some types are fermented in the large intestine. Fiber-rich foods, such as beans, fruits, vegetables and whole grains, contain different proportions of the two types of fiber: soluble and insoluble. Soluble fiber keeps your blood sugar steady by slowing down the absorption of carbs into your system. It also interferes with the absorption of dietary fat and cholesterol, which can help lower your blood cholesterol level. Insoluble fiber prevents constipation by keeping digestive wastes moving through your intestines. Women should consume 25 grams of fiber daily, while men need to get 38 grams each day, according to the Institute of Medicine.
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- American Diabetes Association: Types of Carbohydrates
- Elmhurst College: Carbohydrates -- Classification
- Colorado State University: Dietary Polysaccharides: Structure and Digestion
- Oregon State University: Starch
- American Heart Association: Sugars and Carbohydrates
- Nutrients: Starches, Sugars and Obesity
- Harvard School of Public Health: Health Gains From Whole Grains
- Oklahoma Cooperative Extension Service: Dietary Fiber