Mads Fiil Hjorth has a BSc in exercise physiology and a MSc in human nutrition from the University of Copenhagen. He is a PhD student focusing on physical activity, sedentary behaviour and sleep in paediatric obesity research. In the OPUS school meal study he monitored more than 15,000 days of movement behaviour using accelerometers and fitness-tested approximately 800 children three times. Before the OPUS project he was engaged in international nutrition, more specifically dietary intake and level of physical activity among pregnant Ethiopian women. He has published 7 papers in peer reviewed journals and will hand in his PhD-thesis by February 2014