Carbohydrates (from 'hydrates of carbon') or saccharides (Greek σάκχαρον meaning "sugar") are simple organic compounds that are aldehydes or ketones with many hydroxyl groups added, usually one on each carbon atom that is not part of the aldehyde or ketone functional group. Carbohydrates are the most abundant of the four major classes of biomolecules, which also include proteins, lipids and nucleic acids. They fill numerous roles in living things, such as the storage and transport of energy (starch, glycogen) and structural components (cellulose in plants, chitin in animals). Additionally, carbohydrates and their derivatives play major roles in the working process of the immune system, fertilization, pathogenesis, blood clotting, and development.
major source of fuel for metabolism, being used both as an energy source (glucose being the most important in nature) and in biosynthesis. When monosaccharides are not needed by cells they are quickly converted into another form, such as polysaccharides.
Carbohydrates require less water to digest than proteins or fats and are the most common source of energy. Proteins and fat are vital building components for body tissue and cells, and thus it could be considered advisable not to deplete such resources by necessitating their use in energy production.
Carbohydrates are not essential nutrients: the body can obtain all its energy from protein and fats [3] [4]. The brain cannot burn fat and needs glucose for energy, but the body can make this glucose from protein. Carbohydrates and proteins, contain 4 kilocalories per gram while fats contain 9 kilocalories and alcohol contains 7 kilocalories per gram.[citation needed]
Foods that are high in carbohydrates include breads, pastas, beans, potatoes, bran, rice and cereals.
Based on evidence for risk of heart disease and obesity, the Institute of Medicine recommends that American and Canadian adults get between 40-65% of dietary energy from carbohydrates.[5] The Food and Agriculture Organization and World Health Organization jointly recommend that national dietary guidelines set a goal of 55-75% of total energy from carbohydrates, but only 10% should be from Free sugars (their definition of simple carbohydrates).[6]
The distinction between "good carbs" and "bad carbs" is an important attribute of low-carbohydrate diets, which promote a reduction in the consumption of grains and starches in favor of protein. The result is a reduction in insulin levels used to metabolize sugars, and an increase in the use of fat for energy through ketosis, a process also known as Rabbit starvation.
2007-09-25 21:59:56
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answer #1
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answered by Pebble 4
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Carbohydrates are the elements in our diet which come from starch type foods. E.g. Potatoes, bread, pasta etc. The body breaks them down to blood sugars - as it does all foods. They are important in our diet as they provide energy and heat in an accessible way. As complex starches they are released relatively slowly into the blood stream so last some time to keep the body on an even keel.
2007-09-25 22:19:17
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answer #2
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answered by Anonymous
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