Carbohydrates often get clumped together in two extreme categories: good and bad. Carbohydrates are the body's primary source of energy. Everyone needs them, but it's important to known which ones are good for you and which ones aren't.
Often referred to as simple or complex carbohydrates, the three types of carbohydrates — sugar, starch and fiber — all have a place in your diet. Simple carbs, which include sugar, are monosaccharides and disaccharides. Complex carbs, which include starches and fiber, are polysaccharides.
Basic Carbohydrate Facts
The classification of carbohydrates depends on their chemical structure. Monosaccharides are the simplest form of carbs. These include glucose, fructose and galactose. Glucose is commonly referred to as blood sugar and naturally occurs in fruits and sweeteners. Fructose is fruit sugar and is also the sugar in honey and vegetables. Galactose helps form lactose.
Disaccharides are sugars that contain two monosaccharides linked together. They will eventually be broken down into two separate carbohydrates. Sucrose, lactose and maltose are disaccharides. Sucrose, or plain table sugar, is made of glucose and fructose. Lactose, the sugar found in milk, contains glucose and galactose. Maltose is made of two glucose units and is found in germinating grains.
Polysaccharides are the most complex of carbohydrates. They are the starches and fiber in the diet. They are made of many monosaccharides joined together.
Simple Carbohydrates for Energy
Carbohydrates are the main source of energy for the body. Specifically, the brain prefers glucose over anything else. Simple sugars are easily used for energy and are rapidly absorbed by the body, because they can be broken down quickly in to glucose.
Fructose and sucrose are natural sugars found in fruits and vegetables. Lactose is the natural sugar in milk. When you obtain natural sugar from whole foods such as these, you get a boost of energy while consuming vital nutrients.
Added sugars, or sugar that is added during food processing, 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.
Starches for Energy
Starches can be broken down into glucose to provide energy for the body. Different types of starches are digested at varying rates. These include slowly digestible starch, rapidly digestible starch and resistant starch.
Slowly digestible starch gives you long-term energy and helps you feel full. Rapidly digestible starch, such as highly processed grains, digests quickly and can spike blood sugar. The third type, called resistant starch, isn't digested; it’s fermented in the large intestine and is great for gut health.
Starchy foods deliver essential vitamins, minerals and fiber. Examples of these foods include whole grains, peas, beans, corn, pasta, rice and potatoes. Many of these starchy foods, such as peas and beans, are also sources of protein. Avoid refined grains and go with whole grains to get the full nutritional benefit.
Fiber and Its Health Benefits
When you consume fiber, most of it goes through your digestive tract without being digested. 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 helps bind to fat and cholesterol and removes it from the body, which can help lower your blood cholesterol level. Soluble fiber can be found in citrus fruits, apples, legumes and oats.
Insoluble fiber prevents constipation by keeping digestive wastes moving through your intestines. This can reduce the risk of hemorrhoids and diverticular disease. Brown rice, oats, popcorn, nuts and seeds are sources of insoluble fiber.
Fiber passes through the body, so it is not a source of energy or calories. 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
- American Heart Association: Sugars and Carbohydrates
- Harvard School of Public Health: Health Gains From Whole Grains
- Oklahoma Cooperative Extension Service: Dietary Fiber
- Journal of Food Science: Starch Structure Influences Its Digestibility: A Review
- LibreTexts: Disaccharides