Klaas R Westerterp is professor of Human Energetics at Maastricht University, The Netherlands. He coordinated the bachelor and master programme Metabolism and Nutrition at the Maastricht University Medical Center and was PhD dean of the Faculty of Health, Medicine and Life Sciences. Among his present fields of interest are energy metabolism and body composition, with special emphasis on observations in daily living conditions using accelerometers to assess physical activity and labelled water to assess energy expenditure. He is active in editorial boards of international scientific journals, e.g. Editor of European Journal of Applied Physiology; Editor in chief of Proceedings of the Nutrition Society.