Jim Ceravolo / ceravoloj@montclair.edu / Montclair State University · CC BY-SA 2.0

Jeffrey M. Friedman discovered leptin, the hormone that signals the brain when the body has stored enough fat, opening a molecular window onto the regulation of body weight that reshaped obesity research. A physician-scientist at Rockefeller University and an investigator of the Howard Hughes Medical Institute, he continues to study the genetic mechanisms underlying weight regulation.