In order to maximise performance and muscular development, you have to be in positive protein balance, meaning you must consume more protein i.e. amino acids than you catabolise (breakdown) during exercise. The body demands more protein from the diet due to micro tears endured by the muscle during resistance training. Most studies state that maximum muscle growth (aka maximal protein fractional synthetic rate) occurs with a protein intake of 20-30g per serving, consequently many trainers and fitness enthusiasts feel that an intake above this is unnecessary. However, new research by Deutz & Wolfe published in the Journal of Clinical Nutrition on November 2012 quashes this theory by stating that total muscle growth is not simply based on the protein synthesis in muscles, but rather it is the net balance between muscle protein synthesis (growth) and the rate of protein breakdown...this is known as the anabolic response. This may seem like a simple theory but previous studies that claimed 20-30g protein per serving is the limit, failed to consider that lots of the protein we ingest is stolen and actually used in other metabolic processes within the body, meaning there is actually a greater need for protein to promote muscle development.
The study reports that there is no practical limit to the anabolic (growth) response seen in muscle when protein is consumed, meaning a structured protein and carbohydrate intake above 20-30g protein is in fact acceptable, suggesting that intakes beyond this (within reason) is not wasted or damaging to health. Common sense must prevail here though as protein intakes that exceed 2-3g protein per kg bodyweight per day could be detrimental to health (Kreider, Wilborn, Taylor et al. 2010). The recommendation is to consume between 20-30g protein per meal or shake, but should you need more than the Department of Health’s recommendation of 1.5-2g protein per kg bodyweight per day, and would therefore like to increase your protein intake to more than 20-30g per serving, say 40-50g, then you can…and your body can apparently deal with it, and utilise it.
Deutz, N, E., & Wolfe, R, R. (2012). Is there a maximal anabolic response to protein intake with a meal. Clinical Nutrition.
Kreider, R, B., Wilborn, C, D., Campbell, B., Almada, A, L., Collins, R., Cooke, M et al, (2010). ISSN exercise & Sport Nutrition Review: Research & Recommendations. Journal of the international society of sports nutrition.7: 1550-2783.