How Protein Works
Protein is the building blocks of our body; made up of long chain amino acids. Protein has numerous functions including catalysing metabolic reactions, DNA replication, responding to stimuli, and transporting molecules from one location to another. I doubt very much you came to this blog to read about how much protein you need for the basic celluar functions!If you are resistance training, strength training or just siting on the sofa your muscles will need to repair and re build at some stage. If your body has sufficient protein before and after this exercise your body won't need to take amino acids from other muscles and instead it will create new fibers through Muscle hypertrophy (increase in in size of skeletal muscle through a growth in size of its component cells); with the correct amount of protein we can repair and re build faster.. but too much protein and we have just wasted money and the left over will be placed as fat cells. So how do we measure enough is enough? Protein Synthesis... i.e how much protein is being synthesized. If the protein is not being synthesized then we know it isn't being used in repair and rebuilding and there just so happens to be studies showing us in a simple way where we tap out.
Lemon Study
Dr Lemon in 1998 conducted research on novice body builders (more experienced body builders have less protein synthesis) and measured the nitrogen balance of the individuals to exam the top protein rate.
The picture below summarizes the lemon literature. As you can see, 1.8g/kg is the point at which additional protein intake ceases to yield any benefits for strength training and only 0.8g/kg for sedentary people. This makes sense as the more stress you put on you body the more protein you would need!
This is fantastic news and shows that around 0.9-1g per kg of lean body weight on your off days is perfect and for endurance athletes anywhere between 1.3-1.6g per kg and finally for the body builders out there a max of 1.8g per kg is all that is required!
To be honest I can see why the round figure is used (1g per lb is 2.2g per kg), I would also forgive anyone for just rounding up to 2g per kilo as well.
For me, I might stick at 2g on training days and 1g on off days! There is some evidance that people who are just starting out may synthesize slightly more then 1.8, so rounding makes sense.
End Results?
- Full proteins of 1g per kg of Lean Meass on non training days is sufficient
- Full proteins of 1.5g per kg of Lean Mass for runners and other endurance atheles
- Full proteins of 1.8g per kg of Lean Mass for body builders
References
Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. Lemon PW, Tarnopolsky MA, MacDougall JD, Atkinson SA. J Appl Physiol. 1992 Aug;73(2):767-75.
Effects of exercise on dietary protein requirements. Lemon PW. Int J Sport Nutr. 1998 Dec;8(4):426-47.