Abstract
Introduction: Training can cause stress to an athlete, changing their physical and psychological well-being, and progressing from acute to chronic fatigue (overtraining). Athletes must be monitored closely to ensure training can deliver the desired effects on the athlete's well-being and performance. In this sense, physiological, biochemical, metabolic, and subjective performance measures are all options for monitoring the athlete, including prioritizing the relationship between metabolism and functional nutrition. Objective: It was to carry out a systematic review to elucidate and describe the importance of metabolic tracking and nutrological care in athletes. Methods: The PRISMA Platform systematic review rules were followed. The research was carried out from October to November 2025 in the Scopus, PubMed, Science Direct, Scielo, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 127 articles were found, and 46 articles were evaluated, and 34 were included in this systematic review. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 14 studies with a high risk of bias and 33 studies that did not meet GRADE. Most studies showed homogeneity in their results, with X2 =69.5%>50%. The biases did not compromise the scientific basis of the studies. It was concluded that subjective well-being responded consistently to training stress, deteriorating with increased and chronic training and improving with reduced training. Athletes need to consume adequate energy in the quantity and timing of intake during periods of high-intensity and/or long-duration training to maintain health and maximize training outcomes. Low energy availability can result in unwanted loss of muscle mass, menstrual dysfunction, hormonal disturbances, suboptimal bone density, an increased risk of fatigue, injury and illness, impaired adaptation, and a prolonged recovery process.