“Eat here (and) diet home” is a sign that has been posted in many restaurants. The sign has been cited in print since at least 1932, when it was featured in the syndicated newspaper column “Believe It Or Not” by Robert L. Ripley.
 
     
26 March 1932, The Arkansas Gazette (Little Rock, AR), “Believe It Or Not” by Robert L. Ripley, pg. 20, col. 3:
EAT HERE
AND
DIET HOME
(Sign.—ed.)
RESTAURANT—OWNED BY F. J> BROOKER, Armonk, N.Y.
 
20 November 1938, Lexington (KY) Sunday Herald-Leader, “Believe It Or Not” by Robert L. Ripley, pg. 29, col. 3:
EAT HERE
AND
DIET HOME
SIGN IN MANITOWANING
Ontario
 
15 November 1948, Rockford (IL) Register-Republic, “Hollywood” by Bob Thomas (AP), pg. 24, col. 4:
Frank note outside a Beverly Hills eatery: “Eat here, diet Home.”
 
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Around San Antonio
By Pauline T. Newton
Charleston, SC: Arcadia Publishing
1999
Pg. 79:
The Gothic-like atmosphere of the restaurant, as well as its sign that reads, “Eat Here, Diet Home,” adds to its appeal.
 
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Andoshen, Pa.
By Darryl Ponicsan
San Jose, CA: Authors Choice Press
2001
Pg. 47:
Right above the menu Ella’s mother had taped two hand-lettered signs that she composed herself:
 
EAT HERE
DIET HOME!
 
Twitter
Senor CHO Hayashi
‏@SenorCHO
Sign at restaurant reads: Eat here diet home
9:21 AM - 26 May 2009
 
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Cape Cod National Seashore:
The First 50 Years
By Daniel Lombardo
Charleston, SC: Arcadia Publishing
2010
Pg. 52:
Signs above the vendor window read, “Where the ‘elite’ meet to eat,” “T-Bones 25 cents, With Meat $2.50,” “Eat Here Diet Home,” ...
 
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Mrs. Brower’s Sayings
By Lillian Brower
Xlibris Corporation (Xlibris.com)
2016
Pg. ?:
Sign in a restaurant: Eat here; Diet home.