Abstract
BACKGROUND: This study aimed to compare the Athlete Diet Index (ADI) and body composition between professional and nonprofessional athletes to better understand how differences in training and nutrition impact athletic performance and health. METHOD: A comparative cross-sectional design was used to analyze 183 athletes (99 professional, 84 nonprofessional) from various sports disciplines in Tehran. Data were collected on body composition parameters, including fat mass (FM) and fat free mass (FM) using bioelectrical impedance analysis (BIA) and the ADI, a validated tool for assessing diet quality. RESULTS: The results revealed that professional athletes had significantly lower FM percentages (16.2% ± 7.1%) and higher FFM percentages (80.8% ± 6.8%) compared to their nonprofessional counterparts (FM 18.8% ± 9.9%, FFM 78.0% ± 9.6%). Additionally, professional athletes exhibited higher ADI scores, indicating better adherence to sports nutrition guidelines. CONCLUSIONS: These findings highlight the benefits of structured training and personalized nutrition in achieving favorable body composition. This study underscores the importance of personalized nutrition strategies for optimizing athletic health and performance, particularly for nonprofessional athletes who may not have access to professional dietary guidance. Further research is needed to explore the long-term effects of dietary and training interventions on body composition and athletic performance across various athlete populations.