Abstract
Nutritional support is a critical component of care for critically ill patients, impacting their recovery and overall prognosis. Traditional approaches to feeding in the intensive care unit (ICU) have focused on meeting estimated energy requirements, often resulting in unintended consequences such as overfeeding and associated complications. Permissive underfeeding, a concept gaining attention recently, offers a more controlled approach by intentionally providing fewer calories than traditionally recommended. This comprehensive review explores the rationale, evidence, and practical considerations surrounding permissive underfeeding in critically ill patients. We discuss the physiological basis of permissive underfeeding, its potential benefits in mitigating the risks of overfeeding, and the challenges associated with implementation in clinical practice. Through an analysis of critical studies and clinical trials, we evaluate the comparative effectiveness of permissive underfeeding versus traditional feeding methods and examine its impact on patient outcomes. Recommendations for patient selection, monitoring, and future research directions are provided to guide clinicians in optimizing nutritional support strategies for critically ill individuals. By considering the role of permissive underfeeding alongside traditional feeding approaches, healthcare professionals can tailor nutritional interventions to individual patient needs, ultimately improving outcomes in the ICU.