Researchers at the Center for Exercise, Nutrition, and Preventive Health at Baylor University decided to study the effects of whey protein supplementation over ten weeks of heavy-resistance training. Three groups of supplements were assigned to thirty-six male subjects in a double blind manner.
(For newer readers, double-blind, placebo controlled studies are the gold standard in research. Since neither researchers nor subjects know what supplement they're getting, everyone involved is forced to be more objective.)
Had you been participating in the study, your daily supplement package would've been one of the following:
1) 40g whey protein plus 8g of casein (WC)
2) 40g of whey, 3g branched-chain amino acids, plus 5g L-glutamine (WBG)
3) Or you may have gotten screwed and received 48g of carb placebo
At zero, five, and ten weeks, researchers would've benchmarked or examined the effects of the supplementation, testing your strength, endurance, anaerobic capacity, body composition, and ability to attract women. (Okay, not that last one!) Then you would've had blood drawn, gotten blasted with X-rays (dual-energy X-ray absorptiometry, a.k.a. DEXA), and been tested for 1 rep max bench and leg press. Next they would've stripped the bar down to 80% of your 1RM and had you rep to failure. Lastly, you'd have been subjected to a 30 second Wingate anaerobic capacity test.
No matter what supplement group you were in (even placebo!) you would have experienced significant increases in 1RM bench and leg press strength after ten weeks. However, greatest gains in fat-free mass and DEXA lean mass would have come to those in the whey-casein group.
Let's look at the numbers. After ten weeks, the placebo group gained an average of zero pounds of lean mass. The whey, amino, glutamine group actually lost 0.2 pounds, and the whey/casein group gained 4.1 pounds of lean mass!
The whey/casein cat is out of the bag. If you want the greatest gains, go with the whey/casein blend. [J Strength Cond Res. 2006 Aug;20(3):643-53]
