Shades of grey

摘要

Who knows how many New Year's resolutions to diet were strangled at birth by Katherine Flegal? A group led by Flegal, an epidemiologist at the US National Center for Health Statistics in Hyattsville, Maryland, published a paper on 2 January that suggested that a bit of extra weight may be no bad thing (K. M. Flegal et at J. Am. Med. Assoc.309,71-82; 2013). In fact, the study — and the media coverage it generated — indicated that people deemed overweight' live longer than those who could fit into a pair of jeans a size or two smaller. As we explore in a News Feature on page 428, the study was not the final word on the matter. Opponents have lined up to criticize the research and its findings. Walter Willett, chair of the nutrition department at the Harvard School of Public Health in Boston, Massachusetts, told US National Public Radio that "this study is really a pile of rubbish, and no one should waste their time reading it".