Obesity must be treated in the same way as climate change if the world is to avoid a global health disaster, a leading British expert has warned.

Professor Philip James believes the obesity epidemic is now too serious to be treated merely as another "lifestyle choice" issue.

Instead he wants to see governments and industry coming together to tackle the causes of obesity just as they have done to limit carbon emissions.

The crisis would not be resolved simply by encouraging people to exercise and eat less, he told the annual meeting of the American Association for the Advancement of Science in Boston.

"Blaming individuals for their personal vulnerability to weight gain is no longer acceptable in a world where the majority is already overweight and obesity is rising everywhere," said Prof James, from the London School of Hygiene and Tropical Medicine, who chairs the International Obesity Taskforce.

He added: "It is naive of ill-informed politicians and food industry executives to place the onus on individuals making 'healthier choices' whilst the environment in which we live is the overwhelming factor amplifying the epidemic.

"It is even more naive to tell people that they just need to make a little change in their eating habits or their daily activity and suddenly the obesity problem will be remarkably easily solved."

More than a billion adults around the world are currently overweight and at least 300 million of them clinically obese. Those figures could more than double by 2015, with Asian populations, who are especially prone to putting on abdominal fat, especially at risk, said Prof James.

Being obese is a major cause of ill health and greatly increases the chances of suffering high blood pressure, heart disease, diabetes and cancer. Globally the number of fat people with diabetes is expected to double to 366 million by 2030, said Prof James.

Prof James said the obesity challenge required a change of attitude from food manufacturers and suppliers as well as strategic action from governments. "It is vital that we move away from the relatively recent domination of foods high in fat, sugar and salt - the junk foods - and restore a healthy balance to our diets," he said.

The press association