Australia is the fifth-fattest country in the OECD, yet unlike the fattest – the US – we do not classify obesity as a disease.

The majority of researchers and doctors, speaking Wednesday's Obesity Australia summit said patients would receive better medical care if obesity were classified.

Currently GPs can only encourage weight loss and tell patients obesity is a "risk factor'' for many life-threatening diseases, including diabetes and heart disease.

Professor John Dixon, of the Baker IDI Heart and Diabetes Institute in Melbourne, said patient care should be the priority.