Once proteins undergo deamination (broken down) they cannot be stored, instead they form urea or organic acids, such as pyruvic acid and kreb cycle intermediates, acting as a reparatory substrate allowing the regeneration of ATP.

Starvation - Tissue proteins are only used in this stage when all stores of fats and glycogen become exhausted. The person usually becomes too weak and death soon occurs.

During marathon running, the body uses up its resources in a specific order - learn this!
  • first of all it uses up muscle glycogen
  • later on in the race, blood-borne fuels such as blood glucose and the much slower reacting fatty acids are used
  • It must be remembered that marathon runners drink glucose drinks in order to maintain their fat reserves.