This chapter provides a comprehensive review of the most up-to-date scientific literature and offers practical solutions throughout, enabling the reader to bring the science to life. The chapter begins with an overview of the unique physiology and metabolism of young athletes and how this affects the nutritional requirements for this population. It then moves into key nutritional principles, including energy and macronutrient (carbohydrate, fat and protein) recommendations and micronutrient recommendations, with a focus on those of particular importance for the young athlete (calcium, vitamin D and iron). Thermoregulation mechanisms specific to young athletes are examined alongside fluid recommendations for this population. There is also a brief discussion on supplements, the risks associated with using them and how to minimise these risks. The practical considerations section includes advice on how to devise an individualised nutrition plan for a young athlete, an example nutrition plan, monitoring anthropometrics in young athletes and also educating the young athlete. There are a number of different recipes for the reader to try and also two example case studies: one that focuses on gaining weight and the other that focuses on (in)appropriate fuelling for training and competition.