Protein supplements are a staple in many athletes’ diet program. Up until now there has been practically no information available on how much protein to consume in a single dose after a workout. Some previous research has shown very good results with a small amount of protein as low as 6g. However, the possibility remains open that a higher dose would have produced even better results in those studies.
Researchers decided to finally test that idea. They had highly trained resistance athletes perform a bout of resistance exercise on five separate occasions. In order to test the effects of a protein dose, they had the athletes consume one of 5 different doses of egg protein after exercise. The drinks contained no protein (control) or 5g, 10g, 20g and 40g of protein. Specific measures of muscle protein synthesis were then determined for the next 4 hours.
The control group (no protein) increased protein synthesis, indicating that exercise alone has a positive effect on muscle protein synthesis. There was a further increase after the 5g dose of protein and yet a further increase after the 10g protein dose. When the dose was bumped to 20g, there was almost a doubling of muscle protein synthesis. When the highest dose of 40g of protein was consumed, there was very little further increase in protein synthesis, indicating the effect plateaus somewhere near 20g.
These results indicate a dose-response relationship between the amount of protein ingested and stimulation of protein synthesis after resistance exercise up to about 20g of dietary protein. Consuming more than 20g per serving results in a marked increase in burning of protein as fuel instead of as a source of protein synthesis.
The take home message: a minimum of 20g of high quality protein providing 9g 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]