Nutritional Behaviors, Hydration Status, Cognitive Function, and Physical Performance in Young Athletes: An Integrated Cross-Sectional Analysis

Background: Athletic performance is influenced by interacting nutritional, psychological, physiological, and hydration-related factors, yet their combined relationships remain insufficiently explored. This study investigated associations between dietary behaviors, psychological characteristics, physical and physiological performance, body composition, and hydration status in young athletes. Methods: A cross-sectional study included 156 male athletes aged 17–22 years. Dietary behaviors were assessed using an Arabic-adapted Adult Eating Behaviour Questionnaire, while psychological characteristics were evaluated using the Test of Attentional and Interpersonal Style. Physical performance was assessed using the Yo-Yo Intermittent Recovery Test Level 1, handgrip strength, and standing broad jump. Body composition was measured by bioelectrical impedance analysis, and hydration status was assessed using urine specific gravity. Pearson correlations with Benjamini–Hochberg false discovery rate correction were used to examine associations. Results: Fruit and vegetable consumption and healthier fat-related behaviors were positively associated with muscular strength, whereas sugar and salt intake were negatively associated with cardiorespiratory fitness. Nutritional awareness, environmental factors, and emotional eating were not significantly associated with physical fitness measures. Attention characteristics showed predominantly broad external and internal attentional profiles, while hydration status was weakly associated with selected attentional characteristics. Conclusions: Overall, dietary quality was more consistently associated with physical performance than nutritional awareness alone. The findings support an integrated approach to athlete health and performance that considers nutritional, psychological, and hydration-related factors.