|Image 1: The whey isolate used in the study - I guess as a scientists you just take whatever you get sponsored ;-) All jokes aside, any other whey isolate will do just as fine.|
A cleverly designed experiment that was (how else could it be ;-) conducted by Stuart Phillips' Exercise Metabolism Research Group at the Department of Kinesiology and Neurology at McMasters University in Hamilton, Canada, could hold the answer to the question, whether the speed with which the amino acids from your post-workout protein shake hit your body actually matters (West. 2011). Instead of using caserin or another slow-digesting protein source as control, Daniel W.D. West and his colleagues effectively eliminated all other possibly interfering variables, such as the exact amino acid composition, the carbohydrate and fat or vitamin and mineral content of the control beverage, by simply comparing the protein synthetic response to strength training (8 sets of 8-10 reps at 10RM on the bilateral leg extension machine) in 8 healthy men after bolus or pulsed (10x2.5g every 20min) ingestion of 25g of whey protein.
|Figure 1: Mean serum blood concentration (nmol/ml) of essential amino acids after bolus (red) or pulsed (blue) ingestion of 25g whey protein; * significantly (p<0.05) greater than pulse, # significantly (p<0.05) greater than bolus (data adapted from West. 2011)|
|Figure 2: Relative increases in mTOR phosphorylation (left) and myofibrillar fractional muscle protein synthesis rates (right) over fasted baseline after bolus or pulsed ingestion of 25g of whey protein (data adapted from West. 2011)|
Exercise the one and only "nutrient partitioner"
These results are obviously important, in that they substantiate the current practice of "getting your fast digested protein in right after exercise", what I personally did yet find even more revealing is the following remark that can be found in the extensive discussion of the results:
An intriguing and important divergence between our ﬁndings and reports in which aminoacidemia resulted in only a transient rise in MPS with infusion of amino acids or with amino acid consumption is that our results were postexercise. It appears that a unique aspect of resistance exercise is to selectively sustain elevated synthetic rates of myoﬁbrillar proteins after protein consumption. In contrast to the effects of protein consumption alone at rest, the current results and our earlier work showed that the highest rates of MPS were observed at 3–5 h postexercise when aminoacidemia had subsided.So, what am I preaching in each and every post? There is only one "nutrient repartitioner" which works: EXERCISE. Now, get your ass to the gym and save the money the supp companies want you to spent on dubious supplements which - even if they worked - don't give you any advantage over what you can accomplish with exercise alone for a container full of tasty whey protein isolate (which ought to be ingested in bolus portions of 25g, of course ;-).