Macro partitioning
Daily supplementation with whey protein (approx. 22g/day) during a 9-month resistance training program significantly augments lean body mass gains compared to isocaloric carbohydrate or soy protein supplements.
If you are doing resistance training, adding about 22 grams of whey protein daily (roughly one scoop) can help you build more muscle than if you took the same amount of soy protein or just carbohydrates. This benefit is seen over a long period (9 months), so don't expect quick miracles from switching protein sources, but prioritize whey for its higher leucine content which supports muscle growth better than soy or carbs when total protein is already adequate.
Lean body mass gains were significantly (p < 0.05) greater in whey (3.3 ± 1.5 kg) than carb (2.3 ± 1.7 kg) and soy (1.8 ± 1.6 kg).
Why this rating
Randomized controlled trial with a long duration (9 months) and double-blind design, though the sample size is moderate (n=63 analyzed).
Source
Whey Protein Supplementation During Resistance Training Augments Lean Body Mass
Jeff S. Volek et al. · Journal of the American College of Nutrition · 2013
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