Obesity should be classed as a disease to remove the stigma that it is "self-inflicted" and encourage those with weight problems to get help, medics have said.
Writing in the BMJ, they said that up to 70 per cent of weight variability was inherited, with 200 genes linked to it.
And they said the rise in obesity was due to “an altered environment” which meant cheap food was readily available.
Latest figures show that 29 per cent of adults in England are obese.
John Wilding, professor of medicine at the institute of ageing and chronic disease at the University of Liverpool, and Vicki Mooney, executive director of the European Coalition for People living with Obesity, said: “Body weight, fat distribution, and risk of complications are strongly influenced by biology - it is not an individual's fault if they develop obesity."
“The recent rapid increase in obesity is not due to genetics but to an altered environment (food availability and cost, physical environment, and social factors).
“Strong links exist with social deprivation; some environments are more obesogenic than others, but again we should not blame individuals. Despite these facts, the prevalent view is that obesity is self inflicted and that it is entirely the individual’s responsibility to do something about it.
The pair pointed out that the World Health Organisation has classed obesity as a disease since 1936.
Prof Wilding is president elect of the World Obesity Federation, while Ms Mooney runs Ireland’s only plus size modelling agency.
"The Oxford Dictionary defines disease as 'a disorder of structure or function ... especially one that produces specific symptoms ... and is not simply a direct result of physical injury” their comment piece says.
"Obesity, in which excess body fat has accumulated to such an extent that health may be adversely affected, meets that definition.
They argued that recognising obesity as a chronic disease rather than a lifestyle choice "should help reduce the stigma and discrimination experienced by many people with obesity" and encourage more people to seek NHS treatment.
In contrast, Dr Richard Pile, a GP from St Albans, said the Oxford Dictionary definition of disease "is so vague that we can classify almost anything as a disease".
Also writing in the BMJ, he said such attitudes would encourage “fatalism” and stop people being motivated to lose weight
"It suggests health professionals will slap themselves on the forehead in a eureka moment, shouting: 'This changes everything.'
"Labelling obesity as a disease risks reducing autonomy, disempowering and robbing people of the intrinsic motivation that is such an important enabler of change.
"It encourages fatalism, promoting the fallacy that genetics are destiny,” he added.
Dr Pile said making obesity a disease may not benefit patients, "but it will benefit healthcare providers and the pharmaceutical industry".
The debate follows calls from the Royal College of Physicians (RCP) in January for the Government and the NHS to recognise obesity as a disease.
The RCP said it wanted to see obesity recognised as an ongoing chronic disease to allow the creation of formal healthcare policies to improve care both in doctors' surgeries and hospitals.