Maintaining muscle is not a simple process. As the body ages beyond your twenties and thirties, the ability to build muscle tissue becomes increasingly difficult. Many sports men and women have no desire to build slabs of muscle, instead want to maintain weight for competition, or lose weight whilst holding on to muscle tone and shape.
This requires a similar, yet reduced regime to those who are targeting muscle gain. Protein quality is vital, as is feeding the body with protein regularly to ensure muscle is not lost during exercise.