Editorial on the original article entitled "Permissive underfeeding of standard enteral feeding in critically ill adults" published in the New England Journal of Medicine on June 18, 2015.

On June 18, 2015, the New England Journal of Medicine published an article entitled "Permissive underfeeding of standard enteral feeding in critically ill adults", which reports the results of a study that examined the impact of prolonged nutritional energy restriction for critically ill patients. The study design was unique in the sense that patients in both groups received similar doses of protein during the intervention, while the non-protein energy intake was reduced in the intervention group. The study showed no differences in outcome between the two study groups. These results add to a growing body of high quality evidence against the dogmatic belief that full enteral or parenteral feeding should be given as early as possible during critical illness to prevent complications. Further research is now needed to address the question of the optimal timing to provide more nutritional support for the benefit of the patients, possibly guided by improved biomarkers that need to be developed and validated, and to investigate underlying mechanisms.