By Rupert Cornwell in Washington
The federal government has acknowledged that obesity can be a disease - opening the way for treatment under Medicare, the largest publicly funded United States health care programme.
Announcing the major policy change, Tommy Thompson, the Health Secretary, said obesity was "a critical public health problem" that affected millions of Americans, often causing them to die prematurely.
Under the new policy, Medicare, which covers about 42 million elderly and disabled Americans, will be flooded with requests from doctors and patients for it to pay for diet regimes, consultations andmore drastic steps such as stomach surgery, costing more than $30,000 (�16,000) an operation.
Medicare said it would decide this autumn which treatments and procedures would be covered. That is likely to set the standards for private medical insurers, who tend to follow guidelines set by Medicare.
About two thirds of Americans are either overweight or obese, according to the National Institutes of Health. The NIH estimates that Americans spend $177bn (�95bn) a year on obesity-related treatment. Medicare spends $75bn (�40bn) a year on dealing with diseases linked to obesity, including diabetes, hypertension, and some forms of cancer.
The NIH says the problem is particularly severe for Medicare patients, with the prevalence of obesity increasing by 45 per cent for people between 60 and 69 in the course of the 1990s.
The decision reverses a long-standing federal government policy whereby "obesity itself cannot be considered an illness". This had made it difficult for people to apply for coverage, unless they suffered from specific diseases such as diabetes.
Health groups generally welcomed the decision. But Senator Tom Harkin of Iowa, leading a legislative campaign to promote exercise in schools and controls on fast-food advertising, said the move was only a "partial solution".
A spokesman for the Center for Consumer Freedom, a pro-food industry group, said Mr Thompson's announcement was "a dumbing down of the term 'disease'". Paul Campos, the author ofThe Obesity Myth said the US was "in the grip of an out-of-control cultural hysteria" over the issue."