It is well understood that whey protein consumed after a weights training session causes rapid entry of amino acids into circulation and subsequent uptake into the muscles to promote muscle recovery and tissue remodelling (ie. drink your protein after the gym for optimal muscle growth). However, Professor Louise Burke and her colleagues at the AIS, Australian Institute of Sport, have done a study on this and the results may surprise you.
One of the more commonly asked question by people in search of improved recovery after training and heightened muscular adaptation is:
"which is better: pre or post training protein?"
To answer this question, Professor Louise Burke and her colleagues at the AIS (and other international research institutions) gave subjects either a placebo drink, a beverage containing 25 grams of whey protein or 15 mini-protein sips every 15 minutes and then performed 45 minutes of lower body resistance training.
Amino acid concentration in the blood was measured at various time points after training, as was the amount of muscle protein synthesis.
Professor Burke and colleagues concluded that,
"There was no difference in the enhancement of the muscle protein synthetic response after exercise. Protein sources producing a slow amino acid release, when consumed before resistance exercise in sufficient amounts, are as effective as rapidly digested proteins in promoting post exercise muscle protein synthesis".
The take home message from these studies suggests that personal preference should dictate whether you consume your whey protein before or after exercise, as both approaches appear to be as good as each other in turning on muscle protein synthesis.
Reference: https://www.ncbi.nlm.nih.gov/pubmed/22617396