Nutritional support is very important for critically ill individuals considering that in this condition there are quite large metabolic changes. The American Society of Parenteral and Enteral Nutrition recommends an adequate protein diet in the early stages of severe illness. Critically ill patients experience inflammation and organ failure, resulting in elevated levels of neutrophil gelatinase-associated lipocalin (NGAL). NGAL has gained significant attention for its potential utility as an early predictor of specific organ injury and response to inflammation. Therefore, this narrative review aims to comprehensively explore the existing literature regarding the association of protein intake with NGAL levels in adult critically ill patients. The literature study method with online-based scientific databases on research engines, including Google Scholar, PubMed, Nature, and ScienceDirect, is used in this study. From this investigation, it was found that adequate protein consumption was linked to considerably lower hospital mortality rates, duration of hospitalization, and may lower NGAL levels in patients in critical condition. Based on the review of data in previous studies, it was shown that a lower protein intake at the beginning and at the mid-end of treatment may be beneficial, providing actionable insights for the care of critically ill patients.