Historical clue formulations

• Low-carb diet creator — 2019-10-13
• Doctor with a well-known diet — 2019-02-01
• ___ diet (early 2000s fad) — 2014-12-15
• Diet doctor — 2009-04-27
• 1970's best seller "Dr. ___ Diet Revolution" — 2007-01-11
• Diet doctor — 2006-07-16
• Diet doctor — 2004-07-07
• Grand Ole Opry's Mr. Guitar — 1995-03-03