Daily Protein Amount for Hypertrophy: The Evolution
In the early days of nutrition, initial recommendations on protein intake, as outlined in the Dietary Reference Intakes (DRI) manual, indicated that the amount needed for an individual to remain healthy was 0.8 g of protein per kilogram of body weight per day. This amount was considered sufficient to ensure the basic functions of the body, such as maintaining the synthesis of enzymes and hormones, as well as preserving muscle mass. However, with the advancement of research in the area of sports nutrition, it was realized that this amount could be insufficient to optimize muscle protein synthesis , especially in physically active individuals.
In 2007, the International Society of Sports Nutrition (ISSN) revised these guidelines and published a more updated recommendation, suggesting that a protein intake of 1.4 to 2.0 g/kg/day for physically active individuals was not only safe but also promoted better adaptations to training. This guideline was widely adopted by athletes and bodybuilders seeking to maximize their results in terms of muscle gain and post-exercise recovery.
In the years that followed, scientific research continued to evolve, further refining recommendations on the ideal amount of protein to maximize the effects of training. Two studies published in 2017 and 2019 provided more precise evidence on the ideal protein intake for muscle development and improved athletic performance. These studies identified that the ideal amount of protein to optimize muscle protein synthesis is approximately 1.6 g/kg/day. This value was determined as the "break point", that is, the amount at which a maximum effect on muscle protein synthesis is observed, without higher intakes providing additional benefits in terms of gaining muscle mass or strength.
Studies have also indicated that there is a confidence interval that varies up to 2.2 g/kg/day, which means that, depending on individual factors such as age, level of training, type of physical activity practiced and quality of protein consumed, it may be beneficial to adjust intake within this range. Thus, the range considered ideal for active individuals is between 1.6 and 2.2 g/kg of body weight per day.
In short, protein intake recommendations have evolved significantly over the years, moving from a more generalist approach focused on maintaining basic body functions to more precise guidelines based on optimizing athletic performance and muscle gain. Currently, it is considered that physically active individuals should consume between 1.6 and 2.2 g/kg/day of protein to ensure best results, based on robust scientific evidence.
Rui Lopes
BMS Nutritionists
Morton, Robert W, et al. “A Systematic Review, Meta-Analysis and Meta-Regression of the Effect of Protein Supplementation on Resistance Training-Induced Gains in Muscle Mass and Strength in Healthy Adults.” British Journal of Sports Medicine, vol. 52, no. 6, 11 July 2017, pp. 376–384, https://doi.org/10.1136/bjsports-2017-097608.
“Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review.” Sports, vol. 7, no. 7, 26 June 2019, p. 154, www.ncbi.nlm.nih.gov/pmc/articles/PMC6680710/, https://doi.org/10.3390/sports7070154.