As criticism mounts that a recent study may have minimized the dangers of obesity (search), federal health officials urged people to focus on the big picture — that extra pounds are harmful, not how much harm they may cause.

"What we don't want is for this debate to continue to confuse people," said Dr. Julie Gerberding (search), director of the Centers for Disease Control and Prevention (search). "Obesity and overweight are critically important health threats in this country. They have many adverse consequences."

Gerberding called a news conference Thursday to discuss the study, which CDC scientists published in April. It concluded obesity causes only about 25,814 deaths a year in the United States — far fewer than the 365,000 deaths estimated months earlier.

Even more surprisingly, it concluded people who were overweight but not obese were less likely to die than those who are skinny or at "ideal" weight.

Scientists from the Harvard School of Public Health, the American Heart Association and the American Cancer Society disagree with both conclusions. They say the study is flawed, mostly because it included people with health problems ranging from cancer to heart disease, who tend to weigh less because of those problems and therefore make pudgy people look healthy by comparison.

Doing this is "looking at people who are thin because they're sick, not who got sick because they're thin," said Dr. Michael Thun, the cancer society's chief epidemiologist.

"If you want to define optimal weight for healthy people, you need to start with healthy people," agreed Dr. Meir Stampfer, chief of epidemiology at Harvard School of Public Health.

Gerberding acknowledged the controversy over this point and said people need to look at the overall evidence of harm from excess pounds. "It's not healthy to be overweight," she said.

Obesity raises the risk of heart disease, some cancers, diabetes and arthritis, and being overweight raises blood pressure and cholesterol, which in turn raise the risk of heart disease, she noted.

Scientists said they were relieved CDC was returning to the big-picture message, that obesity is a serious and growing health problem.

"This issue is far too important to be trivialized over methodological disagreements," Thun said.

"We really can't afford to become complacent about this epidemic of obesity and certainly not based on findings from an analysis" that is flawed, said Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women's Hospital in Boston.

Two other signs suggested the CDC was backing off the report. It's Web site now says the study "estimates that obesity is related to about 112,000 deaths." In fact, the study started with that number and then subtracted the benefits of being modestly overweight, arriving at the 25,814 figure.

The study's author, Katherine Flegal, also was not at the Thursday news conference. Instead, Gerberding and Donna Stroup — authors of the previous study setting obesity-related deaths much higher — did the talking.

The Center for Consumer Freedom, a group with ties to the restaurant and food industry, continues to contend CDC has knowingly misled the public about the scope of the obesity problem. Earlier, higher estimates of harm exaggerate the risk, the group contends.