For years, higher protein intake in critically ill patients was assumed to improve survival. Recent large-scale randomised trial data challenge that assumption directly, showing that very high protein doses of around 2 g/kg/day do not improve mortality, physical function, or quality of life, and may be harmful in certain patient subgroups.
Moderate protein targets of 1.2 to 1.5 g/kg/day are now supported as more appropriate for most critically ill patients, with individualisation required based on condition, phase of illness, and renal replacement status. The evidence also points to functional recovery and quality of life, not mortality alone, as the clinically meaningful endpoints for ICU nutrition research.