A group collectively known as the branched chain amino acids (leucine, isoleucine and valine) have garnered a great deal of scientific investigation over the years. This has mostly been because of their unique ability to be used for energy directly by the muscle itself. All protein has the potential to be used for energy however with all other amino acids this involves transport to the liver, conversion to glucose via the metabolic pathway of gluconeogenesis and release back into the blood stream.
http://ow.ly/pdvBY