Protein as an Energy Source
Carbohydrate is the primary energy source for exercise of shorter duration. During extended exercise, fat becomes an increasingly more important as an energy source. What is often forgotten, however, is that in moderate to high intensity exercise of 45 minutes or more, protein, specifically the branch chain amino acids valine, leucine, and isoleucine, can provide up to 20% of the muscle’s energy needs. Breakdown of protein for energy dramatically impacts muscle recovery.