This series has looked at many factors that influence muscle-building and muscle retention in relation to protein. The evidence thus far clearly illustrates that the need for protein for those who lift weights is FAR less than we have been led to believe. It may be logical that muscle is made of protein and therefore the more of it we ingest the more muscle will be built. What we have learned is that the very act of resistance training lessens the need for protein and it is in fact energy that fuels the growth of new muscle and not protein itself. Protein is merely needed in small amounts to repair the muscle.
Today I’d like to look at protein timing as there is still room to improve upon our gains with the correct protein timing protocol. The timing of protein and amino acid ingestion has been given a great deal of attention lately. When an essential amino acid plus carbohydrate solution was ingested before resistance exercise, the response of muscle anabolism was greater than when this solution was ingested following exercise(1). Many people interpreted these results to mean that athletes should ingest protein before exercise.
A follow-up study by the same research group, however, showed that the difference in the response of muscle anabolism was very little when whey protein was ingested before and after exercise – a completely different result from the free amino acids and carbohydrate mixture(1,2). Thus, there is an interaction of the type of amino acid source and the timing of ingestion, meaning not all proteins are created equally.
The difference is probably explained by the time it takes to digest protein. Since free amino acids do not need to be digested in the gut, the appearance of amino acids into the blood is very rapid. This means that when free amino acids are ingested immediately before exercise, delivery of amino acids to the muscle is very high during exercise. Since protein must be digested, amino acid levels in the arterial blood are not increased rapidly enough to increase delivery so that the anabolic response is similar to that when proteins are ingested following exercise. It is possible that ingestion of protein 15, 20 or even 30 minutes prior to exercise may be advantageous, but no study has looked into this.
Ingestion of other nutrients alongside protein and amino acids seems to be advantageous for creation of an anabolic response. Ingestion of carbohydrates and fat along with protein appears to increase the uptake of amino acids into the muscle from the protein(3,4). These results also support an earlier contention that protein in foods is equally effective as that in supplements for stimulating muscle hypertrophy.
Although there is clearly a place for protein supplements as supplements may be much more convenient to use in certain situations, muscle growth can be optimized by eating high quality protein food sources. These protein sources can be of plant origin as well as these protein sources offer much more than just protein. This fact should not come as much of a surprise as we have evolved as human beings in this manner. Steak and protein powder are relatively new to our diet and far from essential to creating a heavily muscled physique. Until next time,
1. Am J Clin Nutr 2007; 86(2):373-381
2. J Nutr 1999; 129(6):1102-1106
3. Am J Physiol 1998; 274(2 Pt 1):C406-C414
4. Am J Physiol Endocrinol Metab 2005; 288(4):E645-E65
This article was written and researched by Matt Taylor
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