This is a term that many programs, products or meal plans will use in the positive manner of saying that whatever it may be will ‘increase protein synthesis’. This is something that certainly sounds good, but what exactly is it?
Protein synthesis is considered generally in the context of the growth and repair of skeletal muscle utilizing dietary proteins. Broken down further, proteins are composed of amino acids and are responsible for the formation of tissues within the body, and specifically the synthesis of protein is the method by which muscles are constructed. Even without exercise, the human body synthesizes protein from the dietary intake at a rapid rate while the body is growing through adolescence and into young adulthood. The rate at which protein is synthesized slows significantly after age 20 and this is the reason that even among active, highly trained adults, the actual rate of muscle growth will be far less in relative terms to that of a healthy teenager.
For the older individual, other than the ongoing repair that the body undergoes on a daily basis, the muscle tissue in the body becomes more related to how much physical activity the body undergoes. Skeletal muscle will not become larger or stronger through sedentary activity, regardless of protein intake or supplementation without stimulus. Any form of physical activity has it’s own mechanism for exerting damage and stress on a muscle. Whether is from endurance related activities such as long distance running that have the combined effect of cumulative and repetitive movement or explosive activities such as lifting weights that occur in a shorter time span, both damage muscle tissue which is the first step in triggering protein synthesis.
With both forms of activity (longer or shorter duration) the muscle naturally breaks down in a process known as ‘catabolism’. This in a nutshell is the physical separation of the muscle fibers that comprise the skeletal muscle structure. On the flip side, the state at which the body is repairing or building is called ‘anabolism’ where the damaged fiber grows and repairs itself. Essentially, when the body is synthesizing more protein that it consumes through an anabolic process, muscle will be developed.
Often times the focus is on sore, damaged or overused muscle as a result of exercising and when it comes to sports research, the focus has evolved from whether protein should be ingested, but more so on at what point after exercise the ingestion of protein should happen to have the maximum benefit for muscle growth and repair. It has also been emphasized in the research the last few years how the combined effects of consuming protein along with carbohydrates should be taken into consideration.
In regards to carbohydrates in combination with protein consumption post workout, the sports nutrition community supports this practice. By providing a carbohydrate source, this replenishes glycogen to the muscles trained efficiently. When carbohydrates are combined with protein post workout, the catabolic process is halted and the protein synthesis is kick started. One last thing of note is that though this action prevents further breakdown of the affected muscle tissue, it is important to remember that the damage within the muscle doesn’t peak for about 3 days following training. With this in mind, it underlines the importance of the ingestion of proteins through consistent dietary intake to support ongoing repair and protein synthesis.