The Importance of Protein Quality
When it comes to physique enhancement, intense resistance training and the optimal timing of protein ingestion are essential factors for success. But there's one more ingredient to consider: How important is protein quality to this formula?
The answer? -Very important. It appears from a series of studies that not all "high-quality" proteins are equal in how they are digested and how this variable affects protein retention/body composition.
A recent review on this topic provides valuable insights on the type (i.e., source) of protein consumed and how it may affect the anabolic response to resistance exercise. For instance, high-quality proteins such as milk, whey, casein, and soy can support muscle protein synthesis. However, differences in the rate of digestion of these proteins can affect the muscle protein synthesis response (whey and soy are classified as "fast-digesting" proteins and casein is classified as a "slow-digesting" protein).
Another consideration is the fact that ingested soy proteins are directed toward the splanchnic (intestinal) regions rather than muscle tissues, which places milk proteins (whey and casein) at an anabolic advantage over soy proteins in promoting muscle growth (hypertrophy). Another important component in determining the response of muscle protein synthesis is the leucine content of the protein, particularly for the elderly.
In conclusion, ingesting a high-quality protein after resistance training will maximize the anabolic response, and it appears that whey and casein proteins are the best high-quality protein choices.