Nutrition significantly impacts the outcomes of critically ill children in intensive care units (ICUs). Due to the evolving metabolic, neuroendocrine, and immunological disorders associated with severe illness or trauma, there are dynamically changing phases of energy needs requiring tailored macronutrient intake. This study aims to assess the changing dietary needs from the acute phase through recovery, provide recommendations for implementing evidence-based strategies to ensure adequate energy and nutrient provision in pediatric ICUs, and optimize patient outcomes. A comprehensive search of the MEDLINE-PubMed database was conducted, focusing on randomized controlled trials, meta-analyses, and systematic reviews related to the nutrition of critically ill children. The study highlights recent guidelines using the GRADE approach, supplemented by relevant adult studies, current clinical practices, challenges, gaps in knowledge, and future directions for research aimed at improving nutritional interventions. Early personalized, incremental enteral feeding helps mitigate the negative energy balance during the acute phase, aids organ function restoration in the stabilization phase, and supports growth during the recovery phase and beyond. Conversely, early full nutritional support, high protein doses, or isolated micronutrient administration have not demonstrated benefits due to anabolic resistance in these patients. Moreover, early parenteral nutrition during the acute phase may suppress autophagy and lead to worse outcomes. Accurate assessment of nutritional status and monitoring of daily energy and protein needs are crucial. Strong evidence supports the establishment of a dedicated nutritional team and the implementation of individualized nutritional protocols in the ICU to reduce morbidity and mortality in critically ill children.