All the energy we need for life comes from the foods we eat and the fluids we drink. These nutrients are broadly broken into fats, proteins, and carbohydrates. Carbohydrates play an especially important role as they provide the quick energy needed for exercise. Carbohydrates found in foods like grains, fruits, vegetables, beans, and dairy products are your body's favorite source of energy, but this is not the only role that carbs play. They also ensure mental sharpness and aid in the metabolism of fat for energy. Complex carbohydrates are an efficient source of energy that fuels muscle contractions. Once eaten, carbs are broken down into smaller sugars (glucose, fructose, and galactose) to be used as energy for immediate tasks. Any unused glucose will be converted into glycogen and stored in the muscles and liver for future use. Glycogen is the energy source most often used for short, intense bouts of exercise such as sprinting or weightlifting. Because glycogen is stored in muscles, it is immediately accessible. During bursts of activity, the stored glycogen will be converted back to glucose and burned for fuel. This is the typical energy source for the first few minutes of any sport.
