Dietary intake and training load in youth male soccer players during a microcycle: Analysis of intra-week variation and examination of associations between measures

Purpose: Our study aims to 1) characterize and analyze food intake and typical external load in young soccer players over a normal microcycle; 2) correlate energy and macronutrient intake with external training load parameters. Methods: Eighteen high-level junior male soccer players (17.61 ± 0.49 years old) had their nutritional intake and training load assessed during a typical mid-season competitive week in November 2022, which included two matches and a structured training schedule. Anthropometric measurements, following ISAK methodology, were taken by a certified technician. Dietary intake using self-reported food diaries for all days was analyzed. Players wore a GPS device during training and matches to measure various performance metrics (distance covered, player load, accelerations, decelerations, maximal speed, and metabolic power). Results: The results revealed no significant within-week variations of carbohydrate (p = 0.747), protein (p = 0.199), lipid (p = 0.747), and calorie (p = 0.241) intake. Significant differences were observed between training days on total distance (p = 0.001), total distance standardized to minutes (p < 0.001), player load (p = 0.007), player load standardized to minutes (p < 0.001), and meta energy (p = 0.002). Conclusions: Players maintained a consistent diet throughout the week, while training load measures varied significantly across the same microcycle, indicating a lack of nutritional periodization. This highlights the need for better nutritional strategies to support varying training loads. It is crucial to reflect on the importance of this apparently insufficient intake for the health and performance of young athletes. Future investigations should explore the development of tailored nutritional plans to enhance their overall well-being and athletic performance.