"tide me over"

What is the origin of the expression to eat something to "tide me over"?

Just a guess:

Your phrase means to enable to surmount or endure a difficulty as in "money to tide us over during the emergency".

The transitive sense of the verb "tide" means to cause to float with or as if with the tide.

So when something is "tiding you over" you are, in a sense, being temporarily lifted or enabled to float over the emergency!

Main Entry: tide over
Function: transitive verb
Etymology: 2tide
Date: 1821

to enable to surmount or endure a difficulty

Main Entry: 2tide
Function: verb
Inflected Form(s): tid·ed; tid·ing
Date: 1593
intransitive senses : to flow as or in a tide : SURGE
transitive senses : to cause to float with or as if with the tide