It has been clearly established that ingesting protein after a workout augments muscle protein synthesis. While there have been a number of studies comparing different types of protein on this response, no studies have focused on the amount of protein that would elicit optimal increases in protein synthesis. Prominent protein researchers addressed this void in the literature by conducting a dose response study in healthy active men. The protocol involved subjects performing a resistance exercise session on five separate occasions. After exercise, they randomly consumed a drink containing different doses of protein: 0, 5, 10, 20, or 40 grams. The source of protein was egg. Compared to consuming no protein, muscle protein synthesis was increased by 37% after the 5 g dose and 56% after the 10 g dose of protein. The 20 g dose condition increased protein synthesis even further by 97%. When 40 g of egg protein was ingested, there was no further increase in protein synthesis. These results indicate a dose response relationship between the amount of protein ingested and stimulation of protein synthesis after resistance exercise up to 20 grams of dietary protein. At the higher dose, there was a marked increase in protein oxidation suggesting that the extra protein was being used as fuel. This is a landmark study that shows 20 grams of high quality protein providing about 9 grams of essential amino acids is the ideal amount of protein to consume after resistance exercise to maximize protein synthesis.
Moore DR, Robinson MJ, Fry JL, Tang JE, Glover EI, Wilkinson SB, Prior T, Tarnopolsky MA, Phillips SM. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2008 Dec 3. [Epub ahead of print]