Head of Obesity Australia John Funder said doctors could treat co-morbidities such as diabetes in very overweight patients, but there was no Medicare item number to process the treatment of obesity.

Professor Funder said he would work with the Royal Australian College of General Practitioners and other stakeholders to produce guidelines and an information kit for doctors dealing with obese patients.

He said the American Medical Association had recognised obesity as a disease and the Australian government needed to do the same.

''The doctors feel like they're able to help people, they're interested in disease, they're not confessors, they're not interested in what is still often thought of as a personal failing … I think it really opens things up,'' he said.

Doctors had an important role to play in combating obesity because they had the trust of the community, he said, but they needed the right tools to help them educate and counsel patients and tell them about treatment options.

Some doctors felt awkward about broaching the subject or thought that talking about it would not make much difference.

But, he said, the fact that many doctors were themselves overweight could help them talk about the subject with their patients.

''[They could say] I'm not preaching at you, I'm telling you it's not your fault, I'm in the same boat,'' he said.

''Between 80 and 90 per cent of us have got genes that say, eat more than you need, because you never know where the next meal's coming from.''