When you eat carbohydrates enzymes your mouth produces salivary amylase that begins the process of breakdown the carbohydrates. The remaining process of digestion happens in your small intestines where enzymes will break down the large carbohydrate molecules into glucose. This glucose then gets absorbed into your blood steam and is used in several different ways.
One way the glucose is used is for energy that is required by your body cells.
The problem that happens is when there is more glucose from carbohydrates in the blood steam than needed by your cells the excess glucose is stored as glycogen in your liver and muscle tissue . When your blood glucose drop too low your body will take the stored glycogen to replenish the required supply of glucose. When your blood glucose levels are too high your liver and muscle tissue will continue to store the glycogen.
After you body need for energy is met any excess glucose will be converted into fatty acids and then stored as those fat tissues.
But there are some good things about carbohydrates.
They have been found to help regulate nerve tissue. In addition they are the ONLY source of energy for the brain. There are some types of carbohydrates that are required for the growth of healthy bacteria in the intestines for good digestion. Other carbohydrates high in fiber are good for helping to prevent constipation. Foods high in fiber has also been shown to lower the risk for certain diseases such as cancer, heart disease and diabetes.
Jillian Michaels: Discusses The Right Carbohydrates