Carbohydrates As An Energy Source

Carbohydrates belong to the group of nutrients called macronutrients. Macronutrients are the nutrients that are needed by the body in the largest amounts. They also provide the body with calories. Carbohydrates provide the body with energy through calories and the simple sugar glucose. It is important to consume adequate amounts of carbohydrates on a daily basis, because glucose is the body's preferred source of energy.

Types

Carbohydrates are divided into two categories: simple and complex. Simple carbohydrates, also referred to as simple sugars, are carbohydrates that contain only one or two sugar molecules. Simple carbohydrates include glucose, fructose, galactose, maltose, lactose and sucrose. Complex carbohydrates are carbohydrates that contain three or more sugar molecules linked together. Complex carbohydrates include starch, fiber and glycogen.

Physiology

When you eat a carbohydrate, your body breaks it down into the simple sugar glucose. Glucose moves through the digestive tract until it reaches the small intestine. From the small intestine, glucose is absorbed into the bloodstream. The presence of glucose in the bloodstream triggers the release of the hormone insulin from the pancreas. Insulin binds to glucose and carries it to all your tissues and cells so it can be used as energy. Excess glucose is carried to the liver, where it is stored as glycogen.

When you have not eaten for an extended period of time and glucose levels in the bloodstream are low, another hormone, called glucagon, is released from the pancreas. Glucagon triggers the release of glycogen from the liver. The stored glycogen serves as a source of energy until you eat again and the body has access to glucose.

Recommendations

Recommendations for carbohydrate intake are given as an acceptable macronutrient distribution range, or AMDR. The AMDR gives the percentage of your energy, or calories, that should come from a specific nutrient, like carbohydrates. The AMDR for carbohydrates is 45 to 65 percent of your daily calories. For someone on a typical 2,000-calorie per day diet, this would equal 225 to 325 g of carbohydrates per day.

Considerations

When choosing carbohydrates, it is important to remember that not all carbohydrates are created equal. Although all carbohydrates provide you with energy, they have different effects on your body. Foods that are high in sugar and calories will give you energy but do not provide you with any important nutrients, like vitamins and minerals. Carbohydrates that are high in saturated fat, such as baked goods, can lead to weight gain and heart disease. Carbohydrates that contain a lot of nutrients and not a lot of fat will provide you with energy without the negative health effects.

Food Sources

Your diet should contain low amounts of simple carbohydrates and high amounts of complex carbohydrates and fiber. The best sources of carbohydrates include whole grains, whole fruits and vegetables. Legumes, nuts and seeds are also good sources of the carbohydrate fiber.