Associations of Diet Quality and Body Composition with Sleep Quality in Professional Athletes: A Cross-Sectional Study

Aim: Sleep quality is vital for recovery and performance in elite sports. This study investigated the associations between body composition, diet quality, and sleep quality in professional athletes within the context of biological rhythms.Method: In this cross-sectional study of 89 professional athletes (football, volleyball, basketball), body composition was determined via the Jackson-Pollock 7-site skinfold method. Diet quality and sleep quality were assessed using the Healthy Eating Index-2015 (HEI-2015) and Pittsburgh Sleep Quality Index (PSQI), respectively.Results: Most athletes (83.2%) had moderate diet quality and 94.4% reported good sleep quality. No significant association was found between overall diet quality and sleep quality (p=0.723). However, athletes with poor sleep quality had significantly higher body fat percentages (p=0.003). Diet quality significantly differed by training duration (p<0.05) and nutrition knowledge (p=0.034). Sleep quality was significantly associated with smoking and sleep-support supplement use (p<0.05). A weak but significant positive correlation existed between PSQI scores and body fat percentage (r=0.293, p<0.05).Conclusion: Overall diet quality was not directly associated with sleep quality among professional athletes. However, sleep quality was significantly related to body fat percentage as well as several training and lifestyle characteristics. These findings highlight the importance of addressing sleep quality and body composition together when developing nutrition and lifestyle strategies aimed at improving recovery and performance in elite athletes.