Adaptive alterations in metabolism: practical consequences on energy requirements in the severely ill patientFontaine, Erica; Müller, Manfred JbCurrent Opinion in Clinical Nutrition & Metabolic Care: March 2011 - Volume 14 - Issue 2 - p 171–175 doi: 10.1097/MCO.0b013e328342bad4 Nutrition and the intensive care unit: Edited by Mette Berger and Jeffrey I. Mechanick Abstract Author Information Purpose of review: A recent and large multicentre study reports that ICU patients receive less than half of the recommended energy requirement. This review aims at clarifying whether underfeeding is scientifically justified or sustained by evidence-based medicine. Recent findings: There is evidence that optimal nutrition improves clinical outcome of critically ill patients. The deleterious effect of overfeeding ICU patients is now well acknowledged, but underfeeding is not scientifically justified in ICU patients. Total energy expenditure in ICU patients is variable and methods to predict resting energy expenditure are questionable in these patients. Summary: There is a need to measure energy expenditure in clinical practice. When not possible, the current guidelines on artificial nutrition (i.e. 25 kcal/kg per day) should be applied in order to limit underfeeding. aBioénergétique Fondamentale et Appliquée, Université Joseph Fourier, Grenoble Cedex, France bInstitut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-Universität zu Kiel, Düsternbrooker Weg Kiel, Germany Correspondence to Eric Fontaine, INSERM U884, Bioénergétique Fondamentale et Appliquée, Université Joseph Fourier, BP 53, F-38041 Grenoble Cedex, France Tel: +33 476 63 56 01; fax: +33 476 51 42 18; e-mail: firstname.lastname@example.org © 2011 Lippincott Williams & Wilkins, Inc.