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06.12.2010

Fast protein after training? There's room for improvement

A portion of fast proteins after a workout: that's the kind of diet regime that athletes with inside scientific knowledge dare to use. According to a study done at the Institute of Sports Medicine Copenhagen, athletes can tweak this regime to make it even better.

The amino acids in a fast protein like whey enter the bloodstream relatively fast – unlike the amino acids in meat, boiled egg and casein. Fast proteins are best taken before and after a workout. The more amino acids the muscles get after a strength workout, the faster they grow.

Study
The Danes did an experiment with 17 young men. The men didn't do weight training normally, but for the trial they did 10 sets of 8 reps on the leg-extension machine. Immediately after they'd finished their last set [time=0], the men were given either 20 g whey, 20 g casein or just water [control].

Results
In the subjects who took whey, the amino acid concentration rose fast. The figure below shows how the concentration of leucine in particular peaked in the whey group. Below that you see how the insulin level rose, especially in the whey group.

The figure below is more interesting. It shows the muscle cells' protein production. In the whey group this was higher than in the casein group, 1-3.5 hours after intake. But in the period after that, production was higher in the casein group. Over the entire period of measurement (1-6 hours), the muscle growth was almost the same in both groups.

Conclusion
If you take whey after a workout, your muscles will have gone through their amino acid supply after 2-3 hours. You could then take another dose of fast proteins. The researchers themselves favour a different solution: you'd do better to consume both a fast and a slow protein immediately after a training session.

Source:
Am J Physiol Endocrinol Metab. 2011 Jan;300(1):E231-42.

More:
Five months of strength training with and without whey 04.12.2010
Whey is more effective before a workout than after 02.12.2010