The lack of a clear picture from the government on obesity and its effects has darkened the cloud of confusion already hanging over an issue that affects tens of millions of Americans.

That study also pointed to health risks associated with being underweight and suggested that being moderately overweight actually might be healthier than having normal weight.

The Center for Consumer Freedom (CCF), a vocal critic of the 400,000 deaths figure, last week ran full-page advertisements in major media outlets across the country railing against what it called "obesity hype."

The group has demanded that CDC rescind the 400,000 obesity deaths per year estimate and endorse the 26,000 figure as accurate.

Number of Deaths Inconclusive

CDC chief Dr. Julie Gerberding reportedly has said the agency will not use the lower figure in its public health campaigns.

The CDC no longer will attribute any specific number of deaths to obesity, according to a spokesperson quoted in news reports, but instead will use a range of obesity mortality estimates.

The CDC intends to continue emphasizing the damaging effects of obesity on health, whether or not it is the direct cause of death. Achieving an accurate mortality figure is difficult because many obese people have multiple related risk factors, such as diabetes and heart disease, experts say.

BMI Standard Challenged

The government's standard measure of overweight and obesity -- the body-mass index, or BMI, also has fallen under criticism. Anyone with a BMI of 25-29 is considered overweight, while those with a BMI of 30 and above are categorized as obese, according to that standard.

The main problem with BMI seems to be that it is a simple height-weight ratio that dosn't take muscle mass into account. Based on BMI, many professional athletes might be considered overweight.

Yo-Yo Science

The lack of a clear picture from the government on obesity and its effects has darkened the cloud of confusion already hanging over an issue that affects tens of millions of Americans.

"If there were a prize for yo-yo sciencing it would be in research on the 'epidemic of obesity,' said Boston Globe columnist Ellen Goodman, according to a CCF statement. "Somewhere another batch of scientists is working on the next episode of 'As the Research Turns.' But the reaction gives you a hint of how the public has turned,'" she added.