Carbohydrate and nutrition
Carbohydrates containing one, two or at most three units of sugar linked together in a single molecule are referred to as simple carbohydrates. These simple carbohydrates (or simple sugars) are easily identified by their sweet taste. Complex carbohydrates are hundreds or thousands of sugar units linked together in single molecules. The complex carbohydrates can be further sub-divided into high and low fiber complex carbohydrates. Humans cannot digest the high fiber complex carbohydrates which is mainly cellulose. Examples of these foods are lettuce and broccoli. Complex carbohydrates with lots of fiber are rich sources of necessary vitamins and minerals as well as enzymes when in the raw state. Examples of low-fiber, complex carbs are banana, tomato, squash and all cereals and grains (therefore bread and pasta), potatoes and rice. Simple sugars and low-fiber, complex carbs, after digestion, appear in the circulatory system in the simple form, as glucose, on its way to the cells where it is used for energy. Complex carbohydrates are transformed into simple sugars when digested by the enzyme amylase. Amylase is secreted by the salivary glands, which empty into the mouth, and by the pancreas, which empties into the head of the duodenum.
Simple Carbohydrate Sources
Simple carbohydrates include: white and brown sugar, fruit sugar, corn syrup, molasses, honey, white flour, white bread, candy, and alcohol. These foods are usually high in calories and offer less nutritional value than complex carbohydrates. (For more information see the foods high in carbohydrates section.)
Complex Carbohydrate Sources
Complex carbohydrates include: vegetables, whole fruits, rice, pasta, potatoes, grains (brown rice, oats, wheat, barley, corn), and legumes (chick peas, black-eyed peas, lentils, as well as lima, kidney, pinto, soy, and black beans). These foods are better for us because they provide nutritional extras; vitamins, minerals, fiber, protein and fat. (For more information see the foods high in carbohydrates section.)
carbohydrates in foods - by food category
Carbohydrate Energy
Carbohydrates are the most common source of energy in the body and contain 4 kCal per gram.
Carbohydrate Recommended Intake
The Institute of Medicine recommends adults get 40-65% dietary energy from carbohydrates. The Food and Agriculture Organization and World Health Organization recommend between 55-75% of total energy carbohydrates.
Excess Carbohydrate
Excess carbohydrates also causes generalized vascular disease. Consuming too many carbohydrates, especially in combination with too many calories, can increase the level of blood fats known as triglycerides, which is a risk factor for artery disease.