He trained as an endocrinologist but is now a public health physician and conducts research on community and policy actions to prevent childhood and adolescent obesity, and reduce, what he has coined, the ‘obesogenic’ food environment.

He is Co-Chair of World Obesity's Policy & Prevention section and Co-Chair of the Lancet Commission on Obesity. He established the World Health Organisation's first Collaborating Centre for Obesity Prevention, at Deakin University in Melbourne and has also contributed to over 30 WHO consultations and reports on obesity. He leads an international network (INFORMAS) in over 30 countries to monitor and benchmark the healthiness of food environments and the implementation of food policies and actions to reduce obesity.