In critically ill children, appropriate nutritional support can improve short- and long term outcomes. When prescribing nutritional support, clinicians in Pediatric Intensive Care Unit (PICU) have to answer numerous questions. These include how much macro- and micronutrients to provide, when to begin nutrition and, which type of feeding should be preferred i.e. enteral or parenteral nutrition (PN). In case of enteral feeding, the PICU team has to choose between continuous vs. intermittent feeding, polymeric vs. semi-elemental formula. The different phases of critical illness and patient age, nutritional and clinical status at admission must also be considered. The impact of these different nutritional strategies on clinical outcomes must be assessed in well-performed randomized controlled trials. Due to the heterogeneity of the population, small sample size, ethical considerations and multiples confounding factors, interventional studies are rare in this population group, and nutritional guidelines often rely on observational studies, results of which describing worse clinical outcomes associated with overfeeding, poor nutritional status or vitamin D deficiency at PICU admission. In contrast randomized controlled trials have shown that withholding PN for one week in critically ill children may be of benefit. However, many questions still remain including the optimal macro- and micronutrients during the various phases of critical illness all of which require future studies. The aim of this review is to give an overview of the current available studies assessing the effect of different nutritional strategies on clinical and functional outcomes in critically ill children