How much protein is in your post workout shake?
New Research Regarding Post Workout Protein Dosages
A common question I often hear from athletes is, “How much protein do I need to take after a workout…. I see some supplements contain 25g/serving while others boast about containing 40-50g/serving….” New research published earlier this year by Moore et al. sheds light on this popular topic1. His research team looked at how the ingestion of various amounts of egg protein impacted muscle protein synthesis when consumed following a resistance training session. Participants in the study included 6 healthy males (average weight ~190 lbs), with an average age of 22 years. Each male had been resistance training > 4 months prior to the start of the study. On 5 separate occasions, each study subject ingested various amounts of a whole egg protein supplement (0, 5, 10, 20 or 40 grams of protein/serving) following a predetermined resistance training exercise session. Both muscle protein synthesis and whole body leucine oxidation were measured for 4 hours following the sessions. Upon analysis of the data obtained, it was shown that muscle protein synthesis increased in a dose-response manner up to 20 grams of protein.
In other words, with greater amounts of protein (up to 20 grams), greater levels of protein synthesis occurred. However, there was no increase in protein synthesis between 20g vs 40g. Going from 20g to 40g also corresponded with a significant increase in whole body leucine oxidation. This signifies that when consumed following resistance training, dietary amounts of egg protein beyond 20 grams will not enhance protein synthesis. The excess protein is metabolized by the liver (measured via whole body leucine oxidation) and used for other purposes within the body.
Study Limitations
This study provides preliminary evidence to indicating that 20g of egg protein maximizes protein synthesis following a resistance training session. Beyond this amount, protein is broken down and used for other purposes in the body (ie-energy). A limitation of this study is that only males were used. I hypothesize that women would respond slightly different in response to the same amount of post workout dietary protein due to hormonal differences. Additionally, its possible that using a different protein source, such as a whey protein, may have a different effect on protein synthesis. However, I wouldn’t expect to the dose-response relationship to be exceptionally different than that seen in this study.
Final Words
As a final thought, remember that protein is just one piece of the post-workout recovery puzzle. Post workout carbohydrate consumption is also critical during this time frame and will be covered in a later article.
References
1 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. 2009.
2 Photo by Sandstein. Accessed June 13, 2010 from: commons.wikimedia.org/wiki/File:Protein_shake.jpg