Carbohydrates are the body's preferred energy source. Eating carbohydrates provides energy to your muscles, brain and nervous system; facilitates the metabolism of fat; and ensures that the protein in your muscles is not broken down to supply energy. Because carbohydrates are so important to your body's function, any excess carbs you eat will be stored in your liver and muscles.
How Carbohydrates Are Stored
When you eat carbohydrates, they are broken down into small sugar molecules in your stomach. These molecules are transported through your digestive system and then converted into glucose by the liver to make a usable form of energy for the brain and your muscles. Any glucose that is not needed immediately for energy is converted into glycogen and stored for later use. Your body can store around 2,000 calories' worth of glycogen, which can be used when you need more energy than is currently available in your bloodstream.
Loading Up the Liver
Your liver stores the most concentrated amount of glycogen of all the storage sites in your body. It can hold up to about 90 to 110 grams of glycogen at any time, and this glycogen is primarily used to maintain blood sugar levels and energy levels throughout the day. Research published in the "Journal of Clinical Investigation" in 1996 found that approximately 19 percent of the carbohydrates from each meal are stored as liver glycogen.
Massing in the Muscles
Your muscles account for 20 percent to 30 percent of your total mass and therefore provide storage for a larger total amount of glycogen than the liver does. A healthy adult who is well-nourished can have about 400 grams of muscle glycogen. Your muscles are the secondary storage facility, filling up only when the liver has reached its storage capacity. Muscle glycogen is used for energy during prolonged strenuous activity.
Found in Fat
According to a report from Iowa State University Extension, your liver and muscles can store around 500 grams of total carbohydrate as glycogen. If your intake exceeds the amount required to fill your liver and muscle tissue, your liver will convert the excess carbohydrate into glucose and release it into the bloodstream. At this point, insulin released from the pancreas will signal to your fat cells to take up the excess glucose and store it for future use.
- McKinley Health Center: Macronutrients: The Importance of Carbohydrate, Protein, and Fat
- Iowa State University Extension: Carbohydrate
- Journal of Clinical Investigation: Direct Assessment of Liver Glycogen Storage by 13-C Nuclear Magnetic Resonance Spectroscopy and Regulation of Glucose Homeostasis After a Mixed Meal in Normal Subjects
- American Journal of Clinical Nutrition: Use and Storage of Carbohydrate and Fat
- Proceedings of the Nutrition Society: Muscle Glycogen and Metabolic Regulation
- Colorado State University: Physiologic Effects of Insulin