The two recently published position stand by the American College of Sports Medicine (Thomas et al., 2016) and the International Society of Sport Nutrition (Jager et al., 2017) recommend a daily protein consumption of 1.2 or 1.4 to 2.0 g/kg/d, respectively. Furthermore, recent researches advice that regardless of the level of physical activity all people need a higher amount of protein than the recommended by the RDA (0.8 g/kg/d) (Wallace and Frankenfeld, 2017). Indeed, the use of Nitrogen balance calculation to estimate protein needs underestimate the real requirements, particularly in athletes whose protein demands can substantially vary based on the age, sex, body composition, training status and their particular objectives at different stages of the training process.
Even though, the International Society of Sport Nutrition (2017) indicates that in both men and women protein supplementation exerts a small to modest impact on strength development, as stated by Naclerio and Larumbe-Zabala, (2016), from the practical point of view the slightly superior results provided by a higher protein ingestion would have a meaningful impact on athletes. In well-trained individuals, an extra-increment of 2 to 4% in fat-free mass and strength, although statistically modest, these outcomes would be meaningful, particularly if produced after relatively short intervention periods (6 -12 weeks).
The daily macronutrient intake results after considering the optimal amount of food composition and time in which each individual meal needs to be consumed (timing). For active people, the amount of food, involving energy intake and appropriate nutrient proportion is highly influenced by the activities (e.g. rest or training) individuals do before and after eating. For athletes, the training characteristics (exercise modality, volume, intensity and amount of muscle mass involved in each exercise session) is the most influential variable affecting food intake. For these reasons, the optimal food composition, including protein needs, dosing, and quality are being currently recommended on a per meal basis. It has been suggested that a relative dose of 0.25 g of protein kg per meal/intake operates as an optimal supply of high quality protein (Jager et al., 2017). Additionally, a higher amount of up to 0.4 g/kg of protein could be ingested to maximally stimulate muscle protein synthesis and recovery immediately after exercise (Morton et al., 2015) or even at dinner to further stimulate protein synthesis and attenuate muscle catabolism during bed rest (Jager et al., 2017). Once the appropriate total daily protein intake has been achieved, the frequency and patterns with which optimal doses are ingested may serve as a key determinant of overall changes in protein synthetic rates resulting in the optimal daily protein consumption. Research indicates that rates of muscle protein synthesis rise to peak level within 30 min after protein ingestion and are maintained up to 3 h before rapidly beginning to lower to basal rates even though amino acid are still elevated in blood. Mixed meal providing ~0.25 g of high quality proteins every 3 h during resting conditions with a large meal, providing ~0.4g or proteins, consumed after workouts and a small meal with high protein content (>0.25 to 0.40 g) at dinner appears to be a good strategy for promoting optimal training adaptations.
JAGER, R., KERKSICK, C. M., CAMPBELL, B. I., CRIBB, P. J., WELLS, S. D., SKWIAT, T. M., PURPURA, M., ZIEGENFUSS, T. N., FERRANDO, A. A., ARENT, S. M., SMITH-RYAN, A. E., STOUT, J. R., ARCIERO, P. J., ORMSBEE, M. J., TAYLOR, L. W., WILBORN, C. D., KALMAN, D. S., KREIDER, R. B., WILLOUGHBY, D. S., HOFFMAN, J. R., KRZYKOWSKI, J. L. & ANTONIO, J. 2017. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr, 14, 20.
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. & 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.
THOMAS, D. T., ERDMAN, K. A. & BURKE, L. M. 2016. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. J Acad Nutr Diet, 116, 501-28.
WALLACE, T. C. & FRANKENFELD, C. L. 2017. Dietary Protein Intake above the Current RDA and Bone Health: A Systematic Review and Meta-Analysis. J Am Coll Nutr, 1-16.