WASHINGTON (AP) -- Medicare now recognizes obesity as an illness, a change in policy that may allow millions of overweight Americans to make medical claims for treatments such as stomach surgery and diet programs.

Health and Human Services Secretary Tommy Thompson said, "Obesity is a critical public health problem in our country that causes millions of Americans to suffer unnecessary health problems and to die prematurely."

Treating obesity-related illnesses results in billions of dollars in health care costs, Thompson said.

"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," Thompson told a Senate panel on Thursday.

With the removal of language in Medicare policy that said obesity is not an illness, beneficiaries will be able to request a government review of medical evidence to determine whether certain treatments for obesity can be covered.

Though Medicare and Medicaid programs cover sicknesses caused by obesity - including type 2 diabetes, cardiovascular disease, several types of cancer and gallbladder disease - the previous policy meant that weight-loss therapies have often been denied coverage.

"The medical science will now determine whether we provide coverage for the treatments that reduce complications and improve quality of life for the millions of Medicare beneficiaries who are obese," said Mark McClellan, administrator of the federal Centers for Medicare and Medicaid Services, which oversees health insurance programs for the elderly, disabled and poor.

Some detractors of the change said it is based on unsound science.

"We have a tremendously exaggerated fear of higher than average weight in this culture," said University of Colorado law professor Paul Campos, author of "The Obesity Myth."

"What's partly baseless is this notion that the government needs to intervene to make Americans thinner," Campos said.

HHS said the policy change is not expected to immediately alter Medicare coverage, and no figures were provided on potential costs to taxpayers. The Medicare agency said it may meet this fall to review scientific evidence on various surgical procedures related to obesity