From Ergo Log
After a workout muscles recover and grow faster the more amino acids they can absorb from the blood. That's why so many strength athletes drink a shake with whey or another easily absorbed protein after working out. Sports scientists at McMaster University in Canada have discovered that strength athletes benefit more from ingesting the whey in one large portion than in several small ones.
There are indications that proteins have a strong anabolic effect in elderly people if you administer them in concentrated form: to start with you deny your body protein for a number of hours and then you give it a couple of dozen grams at once. We've written about this here, here and here.
Research on protein pulse feeding is popular among athletes who believe in intermittent fasting. Logical, as an increased anabolic effect from a concentrated administration of protein meshes seamlessly with the idea of intermittent fasting.
The Canadians make no comment about intermittent fasting or protein pulsing. Their article is more fundamental.
The researchers got male students to train their upper leg with 8 sets of 10 reps on a leg extension machine and then gave the students proteins. Half of the students were immediately given a giant-size shake containing 25 g whey [BOLUS], the other half were given a mini-shake every 20 minutes containing 2.5 g whey [PULSE]. [A little confusing as we just talked about protein pulses: our apologies.]
The set up for the experiment is shown below.
Throughout the 320 minutes that the researchers monitored the students' blood they found the same amounts of essential amino acids [below left] and leucine [below right] in both the 25 g group and the 10 X 2.5 g group.
But over time there's a clear difference: in the 25 g group [BOLUS] you can see that there was a peak in the essential amino acid and leucine concentration an hour after intake. In the 10 X 2.5 g group [PULSE] there’s no peak.
The excessive amount of essential amino acids and leucine stimulates the production of muscle fibre protein [Myofibrillar FSR] the Canadians discovered when they studied samples of muscle tissue from the subjects.
"In conclusion, we report that BOLUS after resistance exercise is more effective in stimulating myofibrillar protein synthesis than is PULSE", the researchers conclude. "The greater myofibrillar protein synthesis response after BOLUS was associated with greater acute phosphorylation of anabolic signaling proteins that regulate translation initiation. The rapid rise in extracellular essential amino acid concentrations, or possibly of leucine alone, that occurred after BOLUS appears to underpin the greater signal activation and protein synthetic response that are observed after an acute bout of resistance exercise."
Am J Clin Nutr. 2011 Sep;94(3):795-803.