Dr John Baker has been a diabetes physician since 1983 and led the formation of the Diabetes Service at Middlemore Hospital as Clinical Head from 1998-2003.

He co-founded Protemix Corporation Ltd in 1999, a biotechnology company investigating novel compounds for the treatment of diabetes mellitus. He went on to become Chief Medical Officer for Protemix for 2 years before returning to CMDHB in October 2005 to take up a dual role as a physician in Internal Medicine for CMDHB and as Clinical Director for Middlemore Clinical Trials.