During the period of World War I in the United States, there was a rise of anti-German sentiment, and German-sounding foods were renamed. A hamburger was called “liberty steak.”
   
”Notice to the Public—From now on and after Hamburger steak will be known as Liberty Steak; Berlin Ham as Washington Ham. Washington Market” was printed in The Bee (Omaha, NE) on April 10, 1918.  The old name came back after the end of the war.
   
There were other “liberty” renamings. A hamburger was also called a “liberty sandwich” and sauerkraut was called “liberty cabbage.”
 
The terms “freedom fries” (for french fries) and “freedom toast” (for french toast) were used during the 2003 invasion of Iraq.
   
       
10 April 1918, The Bee (Omaha, NE), pg. 6, col. 2 ad:
Notice to the Public—From now on and after Hamburger steak will be known as Liberty Steak; Berlin Ham as Washington Ham. Washington Market, 1408 Douglas.—Adv.
 
Newspapers.com
15 April 1918, Seattle (WA) Star, pg. 1, left masthead:
LIBERTY STEAK? YES
George C. Yeo writes The Star thusly: “Don’t you think the old reliable hamburger steak is under a disadvantage with that kind of a name wished on it in these times?  It is a good old sport, and deserves a better lot, and also on account of its comparative cheapness, will help win the war. let us call it Liberty instead. The name will sound better.”
   
24 April 1918, The Daily Capital Journal (Salem, OR), pg. 6, col. 7:
NO HAMBURG STEAK
Seattle, Wash, April 24.—Seattle has run out of hamburg steak.
 
And what’s more, she’ll never have any more. But there will be plenty of “liberty” steak.
 
The name was changed by the Seattle Meat Dealers’ association last night.
 
Newspapers.com
25 April 1918, Seattle (WA) Star, “Pike Place,” pg. 11, col. 6:
... Stall 43, Liberty steak,  15c lb.; ...
 
Newspapers.com
2 May 1918, Coos Bay Times (Marshfield, OR), pg. 3, col. 5:
LIBERTY STEAK NEW NAME FOR HAMBURG
SEATTLE, Wash., May 2. Seattle has run out of hamburg steak.
 
And what’s more she’ll never have any more. But there will be plenty of “liberty” steak.
 
The name was changed by the Seattle Meat Dealers’ association last night.
 
Newspapers.com
9 May 1918, Escanaba (MI) Morning Press, pg. 1, col. 5:
Hamburger Steak?
No! It’s Liberty
When you’re ordering chopped meat fried into what they used to call Hamburger—just be a little careful of the restaurant proprietor’s nerves hereafter.
 
You see—it’s this way. The word Liberty sounds too good in these war times to be wasting Hun names on American food.
 
So—they call it Liberty steak. It’s no longer Hamburger steak—at least that’s the rule at the Home cafe.
 
Newspapers.com
10 June 1918, Detroit (MI) Free Press, pg. 7, col. 1:
HAMBURGER? NO, NEVER!
LIBERTY STEAK NOW
Special to The Free Press.
Peoria, Ill., June 9.—“Liberty steaks” have supplanted hamburgers in restaurants here. Patrons objected to the German inference in the old name and suggested the more patriotic cognomen. Proprietors readily adopted it.
 
Newspapers.com 
28 June 1918, The State Journal (Lansing, MI), pg. 14, col. 3 ad:
Liberty steak ... 22c
(...)
Liberty cabbage ... 6c
(Bazely Cash Market.—ed.)
     
Newspapers.com
23 March 1941, Davenport (IA) Democrat and Leader, pg. 30, col. 6:
We will not be officially at war until the name hamburger has been changed to liberty steak, and sauer kraut to liberty cabbage….
 
Newspapers.com
8 March 1976, Waterloo (IA) Courier, pg. 5, col. 5:
LIBERTY FOOD
During World War I anti-German feeling was so intense that hamburger was called liberty steak; sauerkraut, liberty cabbage; and a dachsund was a liberty pup.
 
OCLC WorldCat record
Scapegoats, slackers and spies: the portrayal of Germany, Germans and German-Americans by three eastern Iowa newspapers during World War I
Author: Lucinda Lee Stephenson
Publisher: Iowa State University Digital Repository 1985-01-01T08:00:00Z
Dissertation: Thesis / Dissertation ETD
Series: Retrospective Theses and Dissertations
Edition/Format:   Thesis/dissertation : Thesis/dissertation : eBook : English
Summary:
It was a time when sauerkraut became “liberty cabbage” and hamburger became “liberty steak.” Berlin, Iowa, started calling itself Lincoln, Iowa, and scores of people filled court houses across the country to have their German surnames changed to “more patriotic and American” names. All aspects of German culture were frowned upon by loyal patriots of the red, white and blue: things that were once a great source of pride for German-Americans suddenly became a source of shame. America’s participation in World War I sparked a period of national paranoia, hysteria and violence—the likes of which America would not see again until the internment of Japanese-Americans in World War II. For America’s German population, the war caused them to endure years of divided loyalties, misunderstandings and persecution. Hyphenism became a buzz word that emphasized the hyphen between “German-Americans,” and it implied a divided loyalty that was frowned upon by those fortunate enough to be “100 per cent” American. President Woodrow Wilson explained it by saying that “some Americans need hyphens in their names because only part of them came over” when they left the Fatherland for America. Shortly afler the United States entered the conflict, German-Americans found themselves the objects of intense scrutiny.
 
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Replying to @JJRocksUrSox
Get yourself a Liberty Steak or a hotdog with some Liberty Cabbage on it.
6:40 PM · Jan 19, 2019 from Tennessee, USA·Twitter for iPhone