Major nutrological approaches to macronutrients in the performance and body composition of highly trained athletes: a systematic review

Abstract

Introduction: Findings around nutrient timing require appropriate context because factors such as age, gender, fitness level, previous fueling status, diet status, training volume, training intensity, program design, and time before upcoming training or competition can influence the extent to which timing can play a role in the adaptive response to exercise. Thus, nutrient timing is a feeding strategy that in almost all situations can be useful for promoting recovery and training adaptations. Objective: A systematic review was carried out to elucidate the importance of macronutrient consumption by highly trained athletes on performance and body composition. Methods: The present study followed a systematic review model (PRISMA). The search strategy was carried out in PubMed, Cochrane Library, Web of Science, Scopus, and Google Scholar databases, using scientific articles from 2009 to 2021. The low quality of evidence was attributed to case reports, editorials, and brief communications, according to the GRADE instrument. The risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: After the study eligibility process, a total of 42 scientifically favorable articles were found to compose the systematic review. Biases did not compromise the scientific basis of the studies. The amount depends on the mode and intensity of exercise, the quality of protein ingested, and the individual's energy and carbohydrate status. However, it should be noted that there is preliminary evidence that consuming much higher amounts of protein (>3 g/kg/d) may confer a benefit concerning body composition. Concerns that protein intake within this range is unhealthy are unfounded in healthy, exercising individuals. One should try to consume whole foods that contain high-quality protein sources. Timing of protein intake in the period spanning the exercise session can provide several benefits, including improved recovery and greater gains in lean body mass. Essential amino acids and leucine supplements are beneficial for the exercising individual by increasing muscle protein synthesis rates, decreasing muscle protein breakdown, and possibly aiding exercise recovery.