Carbohydrates are the body's main energy source. Carbs are crucial for brain functioning, and also power vital organs including the lungs, heart, liver, and kidneys. The Institute of Medicine suggests 45 to 65 percent of a normal adult diet should consist of good-quality carbohydrates.
Carbohydrate Units:
Monosaccharides, Disaccharides, and Polysaccharides
Monosaccharides are single sugars such as glucose and fructose. Glucose is the type of carb often found in energy drinks, while fructose is fruit sugar. Disaccharides are double sugars such as sucrose and lactose. Sucrose is found in table sugar, while lactose is found in milk. Both monosaccharides and disaccharides are soluble in water. Polysaccharides are complex structures found in starches and fibers. Polysaccharides can either be stored in the liver and muscle and later used for energy or broken down and used for digestion.
Types of Carbs:
Simple Carbs
Simple carbohydrates digest quickly to be used by the body for energy. Simple carbs are found naturally in fruits and milk and other dairy products. Simple carbohydrates are also often found in refined, processed foods. Examples of foods that contain simple carbs include table sugar, corn syrup, soda, cakes, cookies, and candy.
Refined Carbs
Refined carbs are found in processed foods that have been stripped of essential vitamins and nutrients, holding no nutritional value. Diets high in refined carbs have been found to contribute to increased risk of type-II diabetes, certain types of cancers, obesity, cardiovascular disease, and depression. Examples of refined carbohydrate foods include: white pasta, white rice, and sugary breakfast cereals.
Complex Carbs
Complex carbohydrates in their natural form are considered good-quality carbs and are important for a healthy diet. Complex carbs take longer to digest than simple carbs, and are usually high in fiber, nutrient-rich, and provide many benefits including: improved digestion, stabilized blood sugar levels, and longer levels of satiety. Good sources of complex carbs include: beans, whole-grain breads, rice, potatoes, and pasta.
Classifying Carbs
One method used to rate carbohydrates is the Glycemic Index. The Glycemic Index classifies carbs as either High GI or Low GI, depending upon the rate at which they release energy. A High GI indicates a food contains quick-release carbs. Quick-release carbs produce a rise in blood sugar followed by a quick fall, which leads to feelings of lethargy. A Low GI indicates a food contains slow-release carbs. Slow-release carbs keep blood sugar level and are important for maintaining energy.
The majority of a healthy diet should be made up of Low GI foods. Examples of Low GI foods are: couscous, brown rice, most fruits and vegetables, whole wheat, oats, and bran. Foods such that have a High GI ranking, such as white bread, white pasta, white rice, and candy bars, should be avoided.
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Jennifer Murray - Jennifer Murray is a freelance writer specializing in nutrition, weight loss and fitness.
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