1 Oxford Martin Programme on the Future of Food and Nuffield Department of Population Health, University of Oxford, Oxford OX3 7LF, United Kingdom; marco.springmann@dph.ox.ac.uk.
2 Natural Resources Science and Management, University of Minnesota, St Paul, MN 55108.
3 Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA 02115.
4 Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston, MA 02115.