Stacy Sims

First, let’s talk about the role carbohydrates play in providing energy for working muscles, providing fuel for the central nervous system (CNS), enabling and perpetuating fat metabolism, and preventing the use of protein as a primary energy source. Remember, carbohydrates — specifically glucose — are the preferred source of energy for muscle contraction and biologic labor.

Glycogen, which is the term for glucose in its stored form, is limited in its ability to be stored: about 350 g in the muscles and 40 g to 50 g in the liver of a non-obese 70 kg man. The glycogen stored in a particular muscle is used directly by that muscle during exercise; glycogen cannot be “borrowed” from resting muscles. Hence, it is critical to restore glycogen levels in the muscles of the endurance athlete

The minimum daily intake of carbohydrates necessary for survival — that is, for supporting the CNS, red blood cell production, the immune system, and all tissues dependent on glucose — is ~130 g. You need considerably more than that to support any physical activity or exercise