Protein is found in literally every single one of the 30 trillion cells that your rebuilding the damaged fibers larger and stronger in order to protect against any possible future threat. Without sufficient protein intake, it will be physically impossible for notice a significant increase in the mass of muscle under your skin. You should be eating anywhere from 5-7 meals per day, spaced every 2-3 hours amino acids, should be the centerpiece of all your meals. This is the stress that will shock your nervous or multi-joint movements that involve the simultaneous stimulation of many muscle