Katherine Flegal

Katherine Mayhew Flegal is an American epidemiologist and senior scientist at the Center for Disease Control and Prevention's National Center for Health Statistics. She is one of the most highly cited scientists in the field of the epidemiology of obesity according to Thomson Reuters.
Education and career.
Flegal holds a bachelor's degree from the University of California, Berkeley, a PhD from Cornell University, and an MPH from the University of Pittsburgh. In 1987, after working at the University of Michigan's biostatistics department, Flegal began working at the CDC.
Research.
Flegal is well known for a series of influential and highly cited articles on the prevalence of obesity in US children and adults. In addition, she was a major contributor to the development of the 2000 CDC growth charts, used in the US to assess the growth patterns of infants and children. In 2005 Flegal and co-authors from CDC and NIH published a study in JAMA which found that being overweight was associated with lower mortality than normal weight and that obesity was associated with slightly higher mortality. After considerable discussion, the CDC accepted Flegal's figures as correct. Flegal's article received CDC's highest science award, the Charles C. Shepard award, in 2006.
In 2013, Flegal was the lead author of a systematic review and meta-analysis published in "JAMA" regarding the association of overweight and obesity with mortality. In a large sample, drawn from other countries as well as the US, overweight people had lower mortality relative to people of normal weight.
Reaction.
Flegal's 2013 paper was criticized by Walter Willett of the Harvard School of Public Health, who called it a "pile of rubbish ... No one should waste their time reading it." Willett was subsequently admonished for his unseemly behavior towards Flegal in an editorial and feature article in Nature, one of the world's pre-eminent scientific journals.
Soon after Flegal's paper was published, the dean of Harvard Medical School, Jeffrey Scott Flier, convened a panel of experts to discuss the paper at Harvard. The panel met on February 20, 2013, where its members stated that Flegal's paper contained several methodological errors. For example, panelist Frank Hu said that Flegal's selection criteria "ruled out high-quality studies of 6 million people," and that these studies, combined with those Flegal included in her review, showed that the highest survival rates are in people of normal weight. However, many researchers accept the results of Flegal's 2005 and 2013 papers and see them as an illustration of what is known as the obesity paradox.