"Carb loading" is a nutrition strategy often used by athletes to prepare for events lasting several hours. Carbohydrate loading, commonly known as "carb loading" or "carbo-loading," is a nutrition strategy that’s often used by endurance athletes to improve their performance by increasing the amount of fuel stored in the muscles. Carbohydrates serve as the body's main source of energy. The carbs we consume are broken down into glucose, a type of sugar, which is used to fuel cell function. When that energy isn't immediately used, the fuel is converted to glycogen and stored in the liver and muscle tissue. During endurance or high-intensity exercise the body uses more of this store than during lower intensity activities. Carb loading was introduced in the 1960s to help increase athletes' base levels of muscle glycogen prior to endurance events, said David Rogerson (opens in new tab), a principal lecturer in sport and exercise science at Sheffield Hallam University in England. "This is so that when we're doing these prolonged activities like a marathon, we've got more fuel,” he told Live Science. Source
