FIRST, resistance trainers need more protein than the average person for recovery from workouts and fast strength and mass gains. The requirement can be as high as 2 grams of protein,
daily, per pound of lean bodyweight.
Whey protein is a complete protein with a unique balance of amino acids that support growth by both pro-anabolic and anti-catabolic hormonal effects. Whey is super-rich in the critical
pro-anabolic trio of branched chain amino acids (BCAAs). Hard training significantly depletes BCAAs (leucine, isoleucine and valine), so they must be supplemented in abundance--or you're
on a fast track to catabolic no-gain-land.
SECOND, whey protein is known as a "fast protein, it's soluble, and digests and absorbs quickly. It provides very fast repletion of the essential amino acids.
The best recent research suggests that muscle protein synthesis is optimally stimulated by high extracellular concentrations of amino acids, and the best way to achieve this is with high, "jolt" doses of whey protein. These "jolts" should be spaced throughout the day for maximum tissue amino uptake and anabolic stimulation.
THIRD, whey protein enhances athletic performance by increasing the levels of the antioxidant glutathione. Hard training is an oxidative stress, and this contributes to the sensation of fatigue. Several studies have shown that supplementary antioxidants, which quell oxidative stress, improve athletic performance. One study showed directly how whey (not casein) protein supplements produce significant increases of peak power and work capacity as determined by whole leg isokinetic cycle ergometry. Better performance during workouts will result in faster muscle gains--provided your protein and calorie needs are being met.
FOURTH, whey protein contains a special component called glycomacropeptide, or GMP, which helps promote the body's release of Cholecystokinin (CCK), an appetite-suppressing hormone. The GMPs in whey protein isolates (not concentrates--see below for the distinction) prompt the body to produce its own appetite-controlling molecules, thus helping the user to resist the high-carb goodies and the high-fat, high-cal pigouts that tip the muscle-to-fat ratio in the wrong direction.
FIFTH, whey protein and creatine are synergistic in promoting anabolism and strength gains! That's right: the top two anabolic supplements, when combined, actually have an anabolic effect that is greater than when taken separately. In a 6-week study of 36 resistance-training men, those receiving high-dose whey protein (1.2 g/kg/day) combined with creatine monohydrate (0.1 g/kg/day) obtained much better lean mass and strength gains than men on whey alone or placebo.
SIXTH, the lactalbumin of whey protein is very rich in tryptophan, which promotes serotonin production in the brain. This has an "anti-stress" and cortisol-lowering effect, by modulating the pituitary/adrenal axis. Several studies have shown that whey protein supplementation blunts the cortisol response to artificial stress--a very significant finding. Hard training itself is an "artificial stress" which increases blood cortisol. Anything you can do to diminish the cortisol response will aid greatly in the overall anabolic process.