The federal Medicare program yesterday abandoned a long-standing policy that obesity is not a disease, removing what has been a major roadblock for many people trying to get treatment for the burgeoning health problem.

After years of review, the Centers for Medicare & Medicaid Services, which runs the health program for the elderly and disabled, announced it is dropping language that had led the agency to routinely deny coverage for weight-loss therapies.

The decision does not automatically mean any specific treatment will be covered, but it opens the door to what is expected to be a flood of applications from individuals, doctors and companies for Medicare to begin paying for therapies. These include stomach surgery, diet programs, and behavioral and psychological counseling.

"Obesity is a critical public health problem in our country that causes millions of Americans to suffer unnecessary health problems and die prematurely," Health and Human Services Secretary Tommy G. Thompson said in announcing the long-awaited decision. "With this new policy, Medicare will be able to review scientific evidence in order to determine which interventions improve health outcomes for seniors and disabled Americans who are obese."

The move is the latest in a series of steps the federal government has taken to fight the nation's rising obesity problem. It was hailed as a major step by public health experts, anti-obesity advocates and individual doctors.

"Conceptually, this is a huge change, for the medical profession, for insurers, and for employers, to treat this just like any other disease," said Morgan Downey, executive director of the American Obesity Association, an advocacy group that has been lobbying for the change.

Because private insurance companies often pattern their coverage after Medicare, the decision is expected to put strong pressure on them to expand coverage for weight-loss treatments. Representatives from the insurance industry, which recently began scaling back on payments for stomach surgery, welcomed the decision and signaled that companies will take their cues from Medicare.

"We're going to be watching this very closely," said Karen Ignagni, president of America's Health Insurance Plans, the industry's primary trade group. "We're going to be looking at what they are evaluating and what their results are."

In addition to the practical implications of getting insurance to pay for more treatment, many experts said the move would help counter the stigma that is often associated with people who are overweight and obese. That might encourage more doctors to treat the problem like other medical conditions and overweight individuals to seek help, experts said.

"The lack of recognition of obesity as a disease has cast a pall over the field. Now Medicare is saying obesity deserves treatment like any other disease," said Louis J. Aronne, president-elect of the North American Association for the Study of Obesity.

The decision was denounced by critics who contend that the health consequences of being overweight have been exaggerated and any real problem is one of individual responsibility.

"This is truly a dumbing-down of the term 'disease.' This is the only disease that I'm familiar with that you can solve by regularly taking long walks and keeping your mouth shut," said Rick Berman, executive director of the Center for Consumer Freedom, a food-industry-funded advocacy group. "It's terrible to start using taxpayer money like this when there are other legitimate diseases that need to be addressed."

The decision is irrational, given that being underweight is more of a health problem for the elderly than being overweight, said Paul F. Campos of the University of Colorado, who wrote a recent book titled "The Obesity Myth."

"It's not just a bad idea -- it's completely unscientific," Campos said. "We're in the grip of a kind of out-of-control cultural hysteria on this issue that leads to really irrational social decisions, such as making obesity a disease among the elderly."

Sen. Tom Harkin (D-Iowa) called the decision a "partial" improvement. "This is illustrative of the problem we have with Medicare," he said. "If you've got a problem, we'll fix you. Medicare should have programs to prevent obesity."

Harkin is pushing comprehensive legislation that would promote exercise in schools, require nutritional labeling on chain restaurant menus, provide Medicare coverage for screening and prevention services, and give the Federal Trade Commission power to restrict food advertising that targets children.

Because it was unclear exactly what Medicare would pay for, there were no immediate estimates of what the policy change would cost the government.

But Mark McClellan, who heads the Medicare program, said the decision will enable the government to begin paying for treatments that work. The agency is planning a fall meeting to review the scientific evidence on the types of care to cover, with stomach surgery at the top of the list, he said.

"The medical science will now determine whether we provide coverage for treatments that reduce complications and improve quality of life for the millions of Medicare beneficiaries who are obese," he said.

The decision reverses a policy put in place decades ago by the Centers for Medicare and Medicaid's predecessor, which had declared that "obesity itself cannot be considered an illness." The policy made it difficult for obese people to obtain coverage for surgery, nutritional counseling, diet drugs and other treatment unless they were suffering from other recognized diseases, such as diabetes or high blood pressure.

As the number of Americans who are obese has risen dramatically in recent years, doctors, advocates and public health experts have been urging that obesity be considered a distinct disease so the federal government and private insurers would pay for more treatment.

In yesterday's decision, the agency stopped short of declaring obesity a disease, but instead dropped the original language.

"I think that's virtually identical to saying it is a disease," Downey said. "They don't have any reason now to deny coverage on the basis of it not being a disease."

The decision will not affect weight-loss drugs, but Downey said his group plans to press Congress to address that issue the next time it reconsiders Medicare's new prescription drug benefit.

HHS's Tommy G. Thompson called obesity "a critical health problem." Medicare chief Mark McClellan said treatments will be reviewed this fall.