2009 Studies & Research Blog

It’s widely known and accepted that if you want to optimize the post-workout period after a hard weight lifting session, you should be taking in a mixture of both carbohydrates and protein.  The protein will supply the amino acids to help repair the muscle tissues that you’ve just damaged while the carbohydrates will work towards replenishing the muscle glycogen stores which have been depleted after the bout of exercise just performed.

One thing some individuals struggle with is understanding exactly how much protein they should be taking to optimize the process.  

Is more protein always a better thing, or does the body have a limit to how much protein it can effectively use during this post-workout period?

That’s the question that researchers out of the Department of Nutritional Sciences in Connecticut asked recently. They looked at the variations in protein intake with regards to whole-body protein turnover after an endurance exercise session was performed.

They had five male runners consume either a low-protein (0.8 gram/kg), moderate-protein (1.8 gram/kg), or high protein (3.6 kg/kg) diet for four weeks.

After this time, whole body protein turnover was assessed after a 75 minute run at 70% VO2 max.  

The results indicated that there was a higher rate of leucine appearance following the high protein diet, indicating a higher degree of protein breakdown. In addition to this, there was also no difference in protein synthesis across the differing diets, but the plasma branched chain amino acids at rest were greater following the moderate and high protein diets compared with the low protein diet.

Therefore, from these results we can conclude that variations in protein intake after exercise will have an impact on plasma amino acid levels and the rate at which protein turnover takes place.

While it is important to keep in mind the fact that this was taken after endurance exercise, it is still good to keep the practical application of this in the back of your mind when planning out your post-workout nutrition protocol.

Reference:
Bolster, DR. (2007). Postexercise whole-body protein turnover response to three levels of protein intake.  Department of Nutritional Sciences, University Connecticut, CT. Med Sci Sports Exerc. Mar;39(3):480-6.