The food group of carbohydrates contributes the largest percentage of a recommended healthy diet and is what the body breaks down into simple sugars - the major source of energy for the body.
Carbohydrates are a compound of carbon, hydrogen and oxygen. These compounds provide the body with an important source of energy. When broken down in the small intestine, 1 gram becomes 16 kilo joules (3.75kcal) of energy.
Carbohydrates provide the all-important supply of glucose required as fuel for our body tissues. When an adequate supply of carbohydrate is not present in the diet, the body is forced to get its glucose from dietary protein, meaning that there's not as much protein available for the growth and repair of tissues. This can lead to muscle atrophy. So a healthy supply in the diet means that the protein is available to perform its proper function.
There are two different categories of this nutrient, Complex Carbohydrates and Sugars:
- Complex Carbs encompass both starches, which are found in potatoes, bread, rice and pasta and whole grain cereal; and fibre, which is found in plant sources, and doesn't have much nutrient value, but helps to maintain the health of the digestive tract.
- Sugars encompass both Intrinsic sugars which are present in the cell structure of foods, and give things like fruits and vegetables their sweetness; and Extrinsic sugars, that are not part of the cell structure of the food source, like lactose which is the sugar found in dairy. The "non-milk" sugars found in honey and confections are also extrinsic sugars.
Studies have shown that some soluble fibres like oats and fruit pectin, can lower cholesterol and reduce the risk of heart disease. High intake of fibre has also been linked to lower incidence of bowel cancer. However, high sugar intake is known to cause Dental Caries, also known as cavities. Cavities happen because acids are formed when the sugar is fermented by bacteria that live on the tooth surface. High intake of sugars is also linked with conditions such as obesity. Nutritionists recommend eating more Intrinsic sugars and soluble fibres, and limiting the intake of extrinsic sugars and starch, in order to maintain a healthy, balanced diet.