Carbohydrates

Carbohydrates are one of three macronutrients that provide the body with energy ( protein and fats being the other two). The chemical compounds in carbohydrates are found in both simple and complex forms, and in order for the body to use carbohydrates for energy, food must undergo digestion, absorption , and glycolysis . It is recommended that 55 to 60 percent of caloric intake come from carbohydrates.

[edit] Chemical Structure

Carbohydrates are a main source of energy for the body and are made of carbon, hydrogen, and oxygen . Chlorophyll in plants absorbs light energy from the sun. This energy is used in the process of photosynthesis, which allows green plants to take in carbon dioxide and release oxygen and allows for the production of carbohydrates. This process converts the sun's light energy into a form of chemical energy useful to humans. Plants transform carbon dioxide (CO 2 ) from the air, water (H 2 O) from the ground, and energy from the sun into oxygen (O 2 ) and carbohydrates (C 6 H 12 O 6 ) (6 CO 2 + 6 H 2 O + energy = C 6 H 12 O 6 + 6 O 2 ). Most carbohydrates have a ratio of 1:2:1 of carbon, hydrogen, and oxygen, respectively.

Humans and other animals obtain carbohydrates by eating foods that contain them. In order to use the energy contained in the carbohydrates, humans must metabolize , or break down, the structure of the molecule in a process that is opposite that of photosynthesis. It starts with the carbohydrate and oxygen and produces carbon dioxide, water, and energy. The body utilizes the energy and water and rids itself of the carbon dioxide.

[edit] Recommended Intake

At times, carbohydrates have been incorrectly labeled as "fattening." Evidence actually supports the consumption of more, rather than less, starchy foods. Carbohydrates have four calories per gram, while dietary fats contribute nine per gram, so diets high in complex carbohydrates are likely to provide fewer calories than diets high in fat. Recommendations are for 55 to 60 percent of total calories to come from carbohydrates (approximately 275 to 300 grams for a 2,000-calorie diet). The majority of carbohydrate calories should come from complex rather than simple carbohydrates. Of total caloric intake, approximately 45 to 50 percent of calories should be from complex carbohydrates, and 10 percent or less from simple carbohydrates.