Active Voice: Protein Supplementation to Enhance Adaptations to Resistance Exercise Training - Not Supported by Scientific Evidence!

By Paul T. Reidy, Ph.D., and Blake B. Rasmussen, Ph.D.

Paul T. Reidy, Ph.D. Blake B. Rasmussen, Ph.D.
Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily reflect positions or policies of ACSM.

Paul Reidy completed his Ph.D. dissertation in Dr. Rasmussen’s muscle biology lab at the University of Texas Medical Branch (UTMB), Galveston, Texas. He is currently a post-doctoral fellow at the University of Utah, Salt Lake City, Utah.

Blake B. Rasmussen, Ph.D., is the Chair of the Department of Nutrition & Metabolism and the Associate Director of the Center for Recovery, Physical Activity & Nutrition at UTMB in Galveston. Dr. Rasmussen is an active ACSM member.

This commentary presents Dr. Reidy’s and Dr. Rasmussen’s views on the topic of a research article that they had published with their colleagues in the June 2017 issue of
Medicine & Science in Sports & Exercise® (MSSE).

Despite an abundance of conflicting evidence, the belief persists that protein supplementation during resistance exercise training will enhance muscle mass and strength. As such, protein supplementation is a several billion-dollar industry supported by strong dogma. This conception is heavily promoted in the lay population and is a solidified notion for the recreational and even the professional athlete. Unfortunately, this paradigm is perpetuated at times by researchers in the field - despite the impressive collection of scientific findings indicating otherwise!

One important aspect of the ACSM mission is dissemination of accurate information derived from evidence-based research. In general, much emphasis in this ongoing activity of ACSM is given to advancing our understandings of the health and performance implications of participation in sport, exercise, and physical activity. The ACSM Position Stands and Joint Position Statements represent one venue to this end. The Nutrition and Athletic Performance Joint Position Statement dedicates significant attention to the potential of protein supplementation to enhance adaptations to exercise training and metabolism.

We suggest that more skepticism should be given to the promotion of protein supplementation during resistance exercise training to eliminate the current dogma.

We have conducted a considerable amount of work examining whether protein supplementation enhances resistance exercise adaptations in young men. The first of these studies was the most extensive literature review to date of all clinical studies examining this question in both single exercise and longitudinal exercise training studies. The second was a series of publications on our clinical trials that further examined this question.

After more than 6 years of work, this comprehensive and critical review was published in the Journal of Nutrition. We concluded that “although a plethora of single exercise supplement studies show a potent anabolic/metabolic effect with added protein supplementation …. a diminishing supplement effect occurs over a prolonged exposure to the stimulus after exercise training. Furthermore, we found that protein/amino acid supplements, combined with resistance exercise training, produced a positive, albeit minor, effect on the promotion of lean mass growth; a negligible effect on muscle mass; and a negligible to no additional effect on strength.”

We also published findings* in MSSE (see the June 2017 issue) from a large clinical trial, recapitulating these findings. Alongside several other recent reports, these findings demonstrated that although whole body lean mass may be enhanced following resistance exercise training with protein supplementation, there are negligible to minimal effects on muscle mass and strength.

Health professionals should be fully aware of the abundance of evidence demonstrating that, if a well-balanced diet is consumed, the adaptations of resistance exercise training will not be enhanced by protein/amino acid supplementation. Apart from sharing these findings and interpretations with our professional colleagues in this commentary, we believe that it is most important that it be clearly delivered to the lay population.

*The MSSE paper mentioned in the above Active Voice commentary was supported in part by DuPont Nutrition & Health.