Over the last 14 months, the federal government has dramatically reduced its estimate of the number of deaths caused annually by obesity.

March 10, 2004: Study by federal Centers for Disease Control and Prevention researchers published in Journal of the American Medical Association indicates that 400,000 Americans die annually from causes related to excess weight, ranking it second to smoking among the causes of death.

May 7: Science magazine quotes several anonymous sources within the CDC who question the study's methodology.

June 21: Rep. Henry Waxman, a California Democrat, requests an investigation, and two days later CDC starts an internal inquiry.

Aug. 15: CDC researcher Katherine Flegal and colleagues publish a paper in the American Journal of Epidemiology criticizing the study's methods. They publish a second critique in the American Journal of Public Health.

Jan. 18, 2005: The CDC concedes in JAMA that it made an error, reduces annual obesity death estimate to 365,000.

Feb. 9: Internal CDC investigation concludes that the study's methodology and data were flawed.

April 20: Flegal and colleagues publish a new estimate in JAMA, indicating that obesity kills about 112,000 annually, while being moderately overweight is actually beneficial, reducing annual mortality by about 86,000.