Purpose of review Critically ill patients are hypermetabolic and have increased nutrient requirements. Although it is assumed that nutritional support is beneficial in this group of patients there are no well designed clinical trials to test this hypothesis. The rationale for nutritional support, therefore, is based upon clinical judgement. Although it is not known how long a critically ill patient can tolerate what is effectively starvation, the loss of lean tissue which occurs in catabolic patients (20–40 g nitrogen/day) suggests that depletion to a critical level may occur after 14 days. Recent findings Acute kidney injury (AKI) is a syndrome commonly seen in the ICU. It is usually multifactorial rather than the result of a primary renal disease. The difficulty of adequately defining the syndrome has been addressed by the acute dialysis quality initiative, leading to the risk, injury, failure, loss, and end-stage kidney (RIFLE) criteria. Summary Broad consensus in the diagnosis and management of AKI in critical illness is achievable. Standardization of nutritional support by RIFLE classification is urgently needed.