Protein requirements for resistance trained athletes are greater than those that don’t participate in resistance training because extra protein/amino acids are necessary for maintenance of skeletal muscle tissue and performance(1).
The quality and source are crucial variables that must be considered when selecting the type of protein.
Generally speaking, quality is determined by the essential amino acid content of the protein. Essential amino acids cannot be made by the body and must come from food.
The 9 essential amino acids are:
Since there isn’t much research regarding the impact of animal-based protein sources on skeletal muscle adaptations(2), a recent study compared the effects of whey protein concentrate, isolated beef protein, hydrolyzed chicken protein and a maltodextrin control group on body composition, muscle performance, perceived recovery, and gastrointestinal symptoms in resistance-trained individuals.
The primary finding was that protein supplementation, irrespective of the source, improved body composition relative to the control group. These results suggest that the choice of protein didn’t impact muscular strength outcomes, as all experimental groups demonstrated a significant increase in lean body mass and a significant decrease in fat mass, whereas neither of these effects were seen in the control group.
These findings underscore the importance of consuming protein post workout, but also demonstrate that similar improvements in body composition profiles should be expected if an athlete consumes beef protein, chicken protein, or whey protein.
A unique finding of this research is that there was no effect of protein source on muscle protein accretion.
This suggests that as long as athletes consume large enough quantities of a quality protein, the source is not as relevant.
This is consistent with previous research which suggests a “threshold” for anabolic benefits of
protein supplementation that may peak as low as 20 grams(3).
Differences in protein sources are of less relevant when protein quantity is high, approximately 46 grams and comes from either meat or dairy-based sources.
There was no gastrointestinal distress from any of the protein treatments reported in this study, even at a dose of 46 grams of protein post workout.
Individuals looking to optimize body composition should consume ample protein post workout, but the source can be self-selected by the individual’s preference, so Whey-PRO or Whey-ISO are solid choices of animal proteins for post-training.
However, individuals with dairy or lactose intolerances can select animal protein sources free of these allergens and attain similar body composition and muscular adaptations.
References:
1. Biolo, G., et al., An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein. Am J Physiol, 1997. 273(1 Pt 1): p. E122-9.
2. Campbell, W.W., et al., Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistance-training-induced changes in body composition and skeletal muscle in older men. Am J Clin Nutr, 1999. 70(6): p. 1032-9.
3. Moore, D.R., et al., Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr, 2009. 89(1): p. 161-8.
