Tim OLDS is a professor of behavioural epidemiology at the University of South Australia. After completing a PhD in French Studies at the University of Sydney, Tim went on to study exercise science, receiving a second PhD in 1997. His research interests have been in mathematical modelling of cycling performance, population and sports anthropometry, and more recently secular trends in the sleep, fitness, fatness, physical activity and food intake of children and adolescents. He is co-editor of the anthropometry textbook Anthropometrica, and the LifeSize software. He was Project Director for the $4 million Australian National Nutrition and Physical Activity Survey, and for the $3.5 million ADAPT Project, which used 3D anthropometry to match body types with military aircraft. Tim’s current work looks at how people use their time, and how time use impacts on health, using his Multimedia Activity Recall for Children and Adults (MARCA) software. Tim has 215 publications and over $23 million in grants and consultancies. He is a Chief Investigator on the $9 million 12-nation International Study of Childhood Obesity, Lifestyle and Environment (ISCOLE), and has been an advisor on the development of Australian and Canadian physical activity guidelines for children and adolescents. He is a regular columnist for Australasian Scientist, and has contributed to New Philosopher and The Conversation. He has given invited presentations and keynotes in China, Fiji, New Zealand, Sweden, Denmark, Canada, Australia, the UAE and South Korea. he is on the editorial boards of the Journal of Sports Sciences and Sleep Health.