Athletes have been using high-quality, high-protein beverages, particularly dairy-based drinks enriched with whey proteins, during and after exercise to enhance muscle growth. Now, two studies have shown that the most beneficial timing of protein intake is immediately after exercise.
In the first study, researchers led by Stuart Phillips (McMaster University) investigated whether post exercise muscle protein synthesis is different when a large, single dose of whey protein (25 g) is consumed immediately after activity compared with when smaller doses (2.5 g) are consumed 10 times over an extended period. In the second study led by Stefan Pasiakos from the US Army Research Institute of Environmental Medicine, active-duty military personnel consumed a high-protein beverage (10 g protein as essential amino acids) containing 1.87 or 3.5 g leucine while exercising on a stationary bicycle. In both studies, post exercise muscle protein synthesis was evaluated.
Consuming the large bolus of whey protein immediately after exercise increased muscle protein synthesis more than when periodic smaller doses of protein were consumed.
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In the second study, muscle protein synthesis was 33 percent greater after consumption of the leucine-enriched protein beverage than after the lower-leucine drink.
The researchers concluded that muscle metabolism after exercise can be manipulated via dietary means. In terms of the most beneficial timing of protein intake, immediate post exercise consumption appears to be best. Furthermore, leucine may play an especially important role in stimulating muscle growth in the post activity recovery period.
The studies were published in the September 2011 issue of The American Journal of Clinical Nutrition.
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