We all know you need protein to build muscle. The question of just how much you need is a more vexing issue. With widespread confusion on the issue, we thought it was time to let the science speak. Rather than focusing on total daily protein consumption, we’ll discover how much protein you should be consuming after your workout to pack on lean beef.

The Need For Protein Post Workout

When you finish your resistance training workout, you are in a catabolic (muscle wasting state). That is because your training has caused stress to your muscle cells that has actually caused micro tears in the muscle fiber. To return to an anabolic (muscle building) state, you need protein that will start repairing and rebuilding those muscle fibers. 

More is Not Better

In a 2011 landmark study, researchers specifically wanted to discover the optimum dose of protein after exercise for the best muscle protein synthesis. The research focused on six young men who regularly weight tained and weighed, on average, 190 pounds. Before the study began they were on a moderate protein diet of 1.4 g/kg/day for two days. They then undertook five different leg training sessions and were given five different doses of egg-derived protein immediately after each session. The dosages were 0,5,10,20 and 40 grams.

After training, the subjects were injected with a form of leucine that could be tracked to see whether it went into muscle or was being used up as energy.

Naturally, the zero protein dose was the worst for protein effects in terms of synthesis in the four hours post exercise. Each successive dose up to 20 grams produced better results. But then things got interesting - at a 20 gram dose of whole egg protein, some of the leucine was being channelled away from protein synthesis in the muscle cell. At 40 grams, an even greater amount of leucine was being diverted from the process. As a result, the rate of protein synthesis was the same at 40 grams as it had been at 20 grams.

While it is true that a greater protein intake did supply a higher level of amino acids into the bloodstream, this did not translate to a greater anabolic effect. This suggests that, if you are taking more than 25 grams of protein in your post workout protein shake, you are wasting the difference when it comes to muscle building. Those extra grams of protein will be used as a fuel source and carbohydrate precursor. 

Finding the Best Protein Source

The key determinant as to the quality of a protein is its classification as either as complete or incomplete protein. Beyond that, however, researchers have devised a number of protein quality measures. Four of the main ones are:
  • Protein Efficiency Ratio (PER)
  • Biological Value (BV)
  • Net Protein Utilization (NPU)
  • Protein Digestibility Corrected Amino Acid Score (PDCAAS)

Protein Efficiency Ratio

The Protein Efficiency Ratio is a measure of the feed efficiency of a protein. It is determined by rodent studies in which rats are fed a diet containing the test protein. The PER value is calculated as the animal’s growth in grams per gram of ingested protein. 

Biological Value

The biological value of a protein is the amount of nitrogen used for tissue formation divided by the amount of nitrogen absorbed from the food. It is expressed as a percentage. BV also uses rodent studies.

Net Protein Utilization

Net protein utilization is a calculation of the ratio of amino acid mass that is converted to proteins to the mass of the amino acids supplied in the test protein. NPU is another value that uses rodent studies.
Protein Digestibility Corrected Amino Acid Score (PDCAAS)

The Protein Digestibility Corrected Amino Acid Score is considered superior to the other three because it is based in human rather than rodent studies. It is worked out by comparing the amount of a limiting amino acid (an essential amino that is low) with the amount of this protein in a high-quality protein source. 

Summary

Taking in a quality protein source after your workout will help you to build muscle faster. However, if you consume more than 25 grams, the excess will be unnecessary for muscle growth. So, rather than spending your money on an expensive mega grams per dose protein source, invest in one that provides 20-25 grams of a better quality protein.
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