Despite some well conducted meta-analysis concluded that protein supplementation is effective to support resistance training outcomes (Cermak et al., 2012, Naclerio and Larumbe-Zabala, 2016), two recently published studies (Reidy et al., 2016, Reidy et al., 2017) indicated that combining resistance training with protein supplementation promote only moderate or minimal benefit on muscle mass gain. These studies analysed the efficacy of different type of proteins compared to the ingestion of only carbohydrates in healthy young, active but not engaged in a regular training programme, who underwent a 12-week hypertrophy oriented protocol. Reidy et al (2017) utilized a subset of the original larger clinical trial investigated in the first study (Reidy et al., 2016). Participants were randomized to one of three groups ingesting a daily 22-g macronutrient dose of (i) protein blend (PB, n = 22, providing 25% soy, 25% whey and 50% Sodium Caseinate), (ii) pure whey protein isolate (WP, n = 15), or (iii) isocaloric maltodextrin condition (MD, n = 17). Supplements were ingested immediately post workout or between meals on the non-training days.
Lean mass, vastus lateralis myofiber-type–specific, cross-sectional area, satellite cell content, and myonuclear addition were assessed before and after the intervention. PB and the pooled protein treatments (PB+WP) exhibited a greater whole-body lean mass %change compared with MD (P = 0.057 for PB) and (P = 0.050 for PB+WP), respectively. All treatments demonstrated similar leg muscle hypertrophy and vastus lateralis myofiber-type–specific cross-sectional area. Increases in myosin heavy chain I and II myofiber, satellite cell content and myonuclei content were also detected after the intervention for the three groups. Authors concluded that protein supplementation during resistance training has a modest effect on whole-body lean mass as compared with training without protein supplementation (ingesting only carbohydrates) and there was no effect on any outcome between protein supplement types (blend vs. whey). According to the authors’ interpretation, both protein supplements did not enhance resistance exercise–induced increases in myofiber hypertrophy, satellite cell content, or myonuclear addition in young healthy men. Authors suggest that as long as protein intake is “adequate”, muscle growth and function will not be influenced by protein supplementation. Even though the previous results are well supported by the statistical analysis, the following points need to be considered:
- Participants were not permitted any food 2 h before exercise and after supplementation. Thus, an exacerbated catabolic state sustained after workouts would have been influenced the observed results. Indeed the most effective strategy for supporting muscle accretion involves the ingestion of ~0.4 g/kg (Morton et al., 2015) mixing with carbohydrate after exercise (Naclerio et al., 2013). In the present study ~22g (between 0.25 to 0.90 g/kg) protein were administered alone.
- The reported dietary analysis was very similar among the studies (Reidy et al., 2016, Reidy et al., 2017). Respect to baseline levels, the two protein groups produced only a modest increase in the daily protein consumption: PB (+15% to +26%) and WP (+19 % to +27.1%) Furthermore, the amount of daily protein reported at week 6th and 12th was in average 1.68 to 1.54; 1.64 to 1.64 and 1.22 to 1.23 g/kg/d for the PB, WP and MD Despite the higher values observed in the two protein treatments, these figures (~1.5 to ~1.6 g/kg/d), even within the recommended minimum range (1.4 to 2.0) to optimize exercise training induced adaptations (JÄGER et al. 2017), still could be considered not optimal to maximize resistance training outcomes in novice individuals that would require up to 2g/kg/d and a higher proportional increase of the daily protein intake (≥ 59.5%) respect to the baseline level (Bosse and Dixon, 2012).
- Participants were recreationally active but not engaged in any regular exercise training programme (<2 sessions at high intensity aerobic or resistance exercises/week), and responses to the intervention would be mostly determined by the exercise and not by minimal changes and diet macronutrient.
In summary, results from the two commented studies indicate that ingesting protein after training would slightly optimise some aspect related to muscle mass gain. Different from what authors conclude, when considering the conducted methodology, even though statistical differences were minimal, from the practical point of view the effect of consuming proteins (Blend and Whey vs. carbohydrates) should not be considered as “non-influential”.
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JÄGER et al. 2017. International Society of Sports Nutrition position stand: protein and exercise. J. Int. Soc. sports. Nutr, 14:20. DOI 10.1186/s12970-017-0177-8.
CERMAK, N. M., RES, P. T., DE GROOT, L. C., SARIS, W. H. & VAN LOON, L. J. 2012. Protein supplementation augments the adaptive response of skeletal muscle to resistance-type exercise training: a meta-analysis. Am J Clin Nutr, 96, 1454-64.
MORTON, R. W., MCGLORY, C. & PHILLIPS, S. M. 2015. Nutritional interventions to augment resistance training-induced skeletal muscle hypertrophy. Front Physiol, 6, 245.
NACLERIO, F., ALKHATIB, A. & JIMENEZ, A. 2013. Effectiveness of Whey Protein Supplement in Resistance Trained Individuals. J Sports Med Doping Stud, 3, 2161-0673.
NACLERIO, F. & LARUMBE-ZABALA, E. 2016. Effects of Whey Protein Alone or as Part of a Multi-ingredient Formulation on Strength, Fat-Free Mass, or Lean Body Mass in Resistance-Trained Individuals: A Meta-analysis. Sports Med, 46, 125-37.
REIDY, P. T., BORACK, M. S., MARKOFSKI, M. M., DICKINSON, J. M., DEER, R. R., HUSAINI, S. H., WALKER, D. K., IGBINIGIE, S., ROBERTSON, S. M., COPE, M. B., MUKHERJEA, R., HALL-PORTER, J. M., JENNINGS, K., VOLPI, E. & RASMUSSEN, B. B. 2016. Protein Supplementation Has Minimal Effects on Muscle Adaptations during Resistance Exercise Training in Young Men: A Double-Blind Randomized Clinical Trial. J Nutr, 146, 1660-9.
REIDY, P. T., FRY, C. S., IGBINIGIE, S., DEER, R. R., JENNINGS, K., COPE, M. B., MUKHERJEA, R., VOLPI, E. & RASMUSSEN, B. B. 2017. Protein Supplementation Does Not Affect Myogenic Adaptations to Resistance Training. Med Sci Sports Exerc, 49, 1197-1208.