About Carbohydrates 

Carbohydrates are one of three macronutrients in our diets that provide calories. The other two are protein and fat.

Carbohydrate is the element in our food which:

1. supplies the energy for the body's automatic activity and for the performance of our daily tasks. The more physical work we perform daily, the more carbohydrates we must proportionately consume.
2. plays a vital part in the digestion, assimilation (metabolism) and oxidation of protein and fat. If we take in more carbohydrate of any kind than is needed for immediate use the unused portion is stored in the liver or converted into fat and deposited in the tissues for future use.

Most carbohydrates come from foods of plant origin. The major simple carbohydrates or sugars are glucose, maltose, fructose, and sucrose which come from plants. Lactose is found in milk.

Sources

We generally think of grains (Bread & Cereal group) as the only source of carbohydrates. In reality carbohydrates come from many other sources that also give us other essential nutrients. Carbohydrates come mainly from plant sources, although milk and many milk products contain some carbohydrates in the form of lactose. They are taken in the form of all foods made up of grain flour, cereals, pasta, potatoes and other vegetables, and also in the form of sugars contained in fruits, syrups, honey and candy, as well as in the pure crystalline form of our familiar table "sugar".

Simple vs. Complex Carbohydrates

Carbohydrates are considered simple or complex based upon their chemical structure and both types contain four calories per gram. Both are also digested into a blood sugar called glucose, which is then used to fuel our bodies for work or exercise.

In the past few years, simple carbohydrates have become known as the 'bad' carbs, while complex carbs seem to be designated as the 'good' ones. 

Simple carbohydrates (with the exception of fructose, fruit sugar) are basically sugars (glucose) so they are immediately absorbed into the bloodstream, causing a rise in blood-sugar levels.  This rapid rise and fall in blood sugar levels caused by excess production of insulin, is not good for our health or our eating habits. Over time, these "sugar spikes" can lead to impaired glucose tolerance, insulin insensitivity and type 2 diabetes.

Many simple carbohydrates contain refined sugars and few essential vitamins and minerals. Examples include fruits, fruit juice, milk, yogurt, honey, molasses and sugar. Glucose is the major kind of simple sugar. Glucose is the basic source of energy for all living things. Glucose supplies the body with quick energy. It occurs naturally in some fruits and vegetables and is also produced in the body by breaking down other foods into glucose. Sweeteners include:

• Fructose: known as fruit sugar. Most plants contain fructose, especially fruits and saps.
• Glucose: sometimes known as blood sugar, sometimes as grape sugar. Nearly all plant foods contain glucose.
• Lactose: commonly known as milk sugar. It is the principal carbohydrate found in milk.
• Maltose: known as malt sugar. Found in grains.
• Sucrose: commonly known as table sugar, beet sugar, or cane sugar. Sucrose occurs in many fruits and some vegetables.
  

Complex carbohydrates often supply energy and other nutrients and fiber that the body needs. They take longer to digest and are usually packed with fiber, vitamins and minerals. Examples are vegetables, breads, cereals, legumes and pasta. Complex carbohydrates include starch which the n the body breaks down into simple sugars. The body has to break down all sugar/starch into glucose to use it. Starch supplies the body with long, sustained energy.

All starchy foods are plant foods. Seeds are the richest source; 70 percent of their weight is starch. Many human societies have a staple grain from which their people derive their food energy. In Canada, the United States, and Europe the staple grain is wheat. Rice is the staple grain of the Orient. Corn is the staple grain of much of South America and the southern United States. The staple grains of other peoples include millet, rye, barley, and oats. In each society a bread, meal, or flour is made from the grain and is then used for many purposes. These staple foods are the major source of food energy for people of the world. They support human activity and energy.

The second important source of starch is the bean and pea family. These include dry beans found at your local supermarket such as lima beans, pinto beans, kidney beans, black-eyed peas, chickpeas (garbanzo beans), and soybeans. These vegetables are about 40 percent starch by weight and also contain a substantial amount of protein.

The third major source of starch is the tubers, such as the potato, yam, and cassava. These serve as the primary starch sources in many non-Western societies.

A second form of complex carbohydrates include dietary fiber which is found in plant cells. Fiber is essential for regulating the body. It is the non-digestible part of plants. Because it is tough and stringy, it does not break down completely in the body. Sources include: Fiber - bran, whole-grain foods, raw vegetables and fruit (especially the seeds and skins), legumes, nuts, seeds and popcorn.
 

Dietary Reccomendations

Most experts recommend that 50 to 60 per cent of the total calories in our diet come from carbohydrates. The bulk of the carbs we consume should be complex and most of the simple ones should come from fruits and milk or yogurt, which also contain vitamins and minerals.

Avoid getting the bulk of your carbs from refined foods high in sugar, since they are usually low in the nutrients we need to maintain health and energy levels.