AUSTRALIANS who overcome clinical obesity through weight-loss surgery can recoup the cost in less than four years, a report finds.

Launched in Adelaide yesterday, at the Royal Australasian College of Surgeons conference, the report found that the cost - about $15,000 - could be saved as a patient became healthier.

Weight-loss surgeon and president of the Obesity Surgery Society of Australia and New Zealand Dr Lilian Kow said the cost could be recovered after about 3 1/2 years.

"Other illnesses linked to weight-loss problems, such as joint problems, heart disease and diabetes, all tend to improve as the weight goes down," Dr Kow said.

"Their need for doctors and prescription medication decreases."

Dr Kow said weight-loss surgery was used as a last resort for patients unable to diet and exercise to keep weight off.