Have I proven my point yet? Probably not. So we’re going to keep the research coming! All of you reading this are most likely well in touch with the literature coming from the Journal of the International Society of Sports Nutrition (JISSN.) If you aren’t, then you are missing out. Their position stand on protein and exercise from Campbell et al clears up the air very nicely on this subject matter. They state under the protein intake recommendations section the following: “controversy has existed over the safety and effectiveness of protein intake above that currently recommended. Currently, the RDA for protein in healthy adults is 0.8 g/kg body weight per day. The purpose of this recommendation was to account for individual differences in protein metabolism, variations in the biological value of protein, and nitrogen losses in the urine and feces. Many factors need to be considered when determining an optimal amount of dietary protein for exercising individuals. These factors include protein quality, energy intake, carbohydrate intake, mode and intensity of exercise, and the timing of the protein intake . The current recommended level of protein intake (0.8 g/kg/day) is estimated to be sufficient to meet the need of nearly all (97.5%) healthy men and women age 19 years and older. This amount of protein intake may be appropriate for non-exercising individuals, but it is likely not sufficient to offset the oxidation of protein/amino acids during exercise (approximately 1–5% of the total energy cost of exercise) nor is it sufficient to provide substrate for lean tissue accretion or for the repair of exercise induced muscle damage. Protein recommendations are based upon nitrogen balance assessment and amino acid tracer studies. The nitrogen balance technique involves quantifying the total amount of dietary protein that enters the body and the total amount of the nitrogen that is excreted. Nitrogen balance studies may underestimate the amount of protein required for optimal function because these studies do not directly relate to exercise performance. Also, it is possible that protein intake above those levels deemed necessary by nitrogen balance studies may improve exercise performance by enhancing energy utilization or stimulating increases in fat-free mass in exercising individuals. Indeed, an abundance of research indicates that those individuals who engage in physical activity/exercise require higher levels of protein intake than 0.8 g/kg body weight per day, regardless of the mode of exercise (i.e. endurance, resistance, etc.) or training state (i.e. recreational, moderately or well-trained). Also, there is a genuine risk in consuming insufficient amounts of protein, especially in the context of exercise; a negative nitrogen balance will likely be created, leading to increased catabolism and impaired recovery from exercise.
Relative to endurance exercise, recommended protein intakes range from of 1.0 g/kg to 1.6 g/kg per day depending on the intensity and duration of the endurance exercise, as well as the training status of the individual. For example, an elite endurance athlete requires a greater level of protein intake approaching the higher end the aforementioned range (1.0 to 1.6 g/kg/day). Additionally, as endurance exercise increases in intensity and duration, there is an increased oxidation of branched-chain amino acids, which creates a demand within the body for protein intakes at the upper end of this range. Strength/power exercise is thought to increase protein requirements even more than endurance exercise, particularly during the initial stages of training and/or sharp increases in volume. Recommendations for strength/power exercise typically range from 1.6 to 2.0 g/kg/day, although some research suggests that protein requirements may actually decrease during training due to biological adaptations that improve net protein retention. Little research has been conducted on exercise activities that are intermittent in nature (e.g., soccer, basketball, mixed martial arts, etc.). In a review focusing on soccer players, a protein intake of 1.4–1.7 g/kg was recommended. Protein intakes within this range (1.4 to 1.7 g/kg/day) are recommended for those engaging in other types of intermittent sports. In summary, it is the position of the International Society of Sport Nutrition that exercising individuals ingest protein ranging from 1.4 to 2.0 g/kg/day. Individuals engaging in endurance exercise should ingest levels at the lower end of this range, individuals engaging in intermittent activities should ingest levels in the middle of this range, and those engaging in strength/power exercise should ingest levels at the upper end of this range” (4.)
The literature goes on and on from researchers like Lemon, Tarnopolsky, Rand, Young, etc. Lemon et al even looked at protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders and found that during the early stages of intensive bodybuilding training, PRO needs are approximately 100% greater than current recommendations (5.) As always, I have more literature below for you to read at your leisure to fully understand protein metabolism in regards to bodybuilders in relation to increased nitrogen retention, aminoacidemia, skeletal muscle protein synthesis, TEF, etc. In terms of practical application, we can see anything as low as 1 gram per pound of bodyweight and upwards of 3 grams per pound of bodyweight to be effective. I feel somewhere in between is the happy medium as we do have caloric restrictions and requirements to hit everyday. I would recommend beginning somewhere in the 1.2-2 grams per pound of bodyweight range, assessing the results, and altering as needed. The main point of this article is to get you thinking and questioning “is there a better way?” Now go out, do more research on your own, implement, experiment, and adjust to favor the results you desire.
References
- A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. Jose Antonio, Anya Ellerbroek, Tobin Silver, Leonel Vargas, Armando Tamayo, Richard Buehn, and Corey A. Peacock. Exercise and Sport Science Laboratory, Nova Southeastern University, Davie, FL, USA. 2016. (https://www.hindawi.com/journals/jnme/2016/9104792/)
- The effects of a high protein diet on indices of health and body composition – a crossover trial in resistance-trained men. Jose Antonio, Anya Ellerbroek, Tobin Silver, Leonel Vargas and Corey Peacock. Journal of the International Society of Sports Nutrition. 2016 (https://jissn.biomedcentral.com/articles/10.1186/s12970-016-0114-2)
- A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women – a follow-up investigation. Jose Antonio, Anya Ellerbroek, Tobin Silver, Steve Orris, Max Scheiner, Adriana Gonzalez and Corey A Peacock. Journal of the International Society of Sports Nutrition. 2015 (https://jissn.biomedcentral.com/articles/10.1186/s12970-015-0100-0)
- International Society of Sports Nutrition position stand: protein and exercise. Bill Campbell, Richard B Kreider, Tim Ziegenfuss, Paul La Bounty, Mike Roberts, Darren Burke, Jamie Landis, Hector Lopez and Jose Antonio. Journal of the International Society of Sports Nutrition. 2007 (https://jissn.biomedcentral.com/articles/10.1186/1550-2783-4-8)
- Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. P. W. Lemon, M. A. Tarnopolsky, J. D. MacDougall, S. A. Atkinson. J Appl Physiol (1985) (https://www.ncbi.nlm.nih.gov/pubmed/1400008)
- Protein requirements and muscle mass/strength changes during intensive training in novice bodybuilders. P. W. Lemon, M. A. Tarnopolsky, J. D. MacDougall, S. A. Atkinson. J Appl Physiol (1985) (https://www.ncbi.nlm.nih.gov/pubmed/1400008)
- Exercise-induced changes in protein metabolism. K. D. Tipton, R. R. Wolfe. Acta Physiol Scand. 1998 (https://www.ncbi.nlm.nih.gov/pubmed/9578384)
- Muscle protein synthesis in response to nutrition and exercise. P. J. Atherton, K. Smith. The Journal of Physiology. 2012 (http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2011.225003/abstract)
- Beyond the zone: protein needs of active individuals. P. W. Lemon. J Am Coll Nutr. 2000 (https://www.ncbi.nlm.nih.gov/pubmed/11023001)
- Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults. William M. Rand, Peter L. Pellett, Vernon R. Young. Am J Clin Nutr. 2003 (https://www.ncbi.nlm.nih.gov/pubmed/12499330)
