ATKINS

Set to 3 different clues across 5 published puzzles, most often “Diet doctor” — The New York Times, Monday, 27 April 2009.

6 letters

Every clue on record, most used first

Diet doctor3 times
The New York Times — Monday, 27 April 2009
1970's best seller "Dr. ___ Diet Revolution"once
The New York Times — Thursday, 11 January 2007
Grand Ole Opry's Mr. Guitaronce
The New York Times — Friday, 3 March 1995