1 From the MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Institute of Metabolic Science, Cambridge, UK (PSP; NGF, e-mail: nita.forouhi@mrc-epid.cam.ac.uk); the University of Reading, Reading, UK (GGCK); and the Department of Archaeology and Anthropology and the McDonald Institute for Archaeological Research, University of Cambridge, Cambridge, UK (TCO).