There are several definitions of high protein diets, for instance, traditional recommendations state that hyper-protein diets are those providing protein intakes greater than 15-16% of total energy, as high as 35% of total calories, or intakes that exceed the RDA (e.g. 0.8 to 1 g of protein per kg body mass).
The traditional concept of defining diet based on energy percentage is misleading and would not reflect the real needs of nutrients based body mass, dimensions and level of physical activity. Instead, high protein diets should always be defined as the amount of protein consumed per unit body weight. Indeed the Nutrition and Athletic Performance joint of the American College of Sports Medicine and Academy of Nutrition and dietitians of Canada published in March 2016 (Thomas et al., 2016) recommends the use of guidelines per kg body mass to allow guidelines to be scaled to the large range in the body sizes of different athletes (p 545).
According to the International Society of Sports Nutrition (Campbell et al., 2007) high protein diets should necessarily exceed 2.0 g/kg/d. Nonetheless ingesting more protein that what an individual would need does not mean that it is necessarily harmful. Previous studies have observed not deleterious effects of moderate (Naclerio et al., 2017) or high (> 3.0 g/kg/d) (Antonio et al., 2016) protein diet in the athletic population. The aforementioned work of Antonio et al. reported no deleterious effects of a high protein diet (2.51–3.32 g/kg/d) over a 1-year period in resistance-trained males. Thus the myth that protein intakes 3-4 times greater than the current RDA cause any harmful effects is not supported.
Recommended open access reading
ANTONIO, J., ELLERBROEK, A., SILVER, T., VARGAS, L., TAMAYO, A., BUEHN, R. & PEACOCK, C. A. 2016. A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. J Nutr Metab, 2016, 9104792.
CAMPBELL, B., KREIDER, R. B., ZIEGENFUSS, T., LA BOUNTY, P., ROBERTS, M., BURKE, D., LANDIS, J., LOPEZ, H. & ANTONIO, J. 2007. International Society of Sports Nutrition position stand: protein and exercise. J. Int. Soc. sports. Nutr, 4, 8.
NACLERIO, F., LARUMBE-ZABALA, E., ASHRAFI, N., SEIJO, M., NIELSEN, B., ALLGROVE, J. & EARNEST, C. P. 2017. Effects of protein-carbohydrate supplementation on immunity and resistance training outcomes: a double-blind, randomized, controlled clinical trial. Eur J Appl Physiol, 117, 267-277.
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.