“If we’re not supposed to eat late-night snacks, why is there a light in the refrigerator?” is a jocular saying that has been cited in print since at least 1999.
   
“If we shouldn’t eat at night, why is there a light in the fridge” is another form of the saying that has been printed on many images. “If we’re not supposed to eat at night, so why is there a light in the fridge?” was posted on Twitter by Saran Limtrakul on November 15, 2010. “If we shouldn’t eat at night why is there a light in the fridge?” was posted on Twitter by Craig Hopkins on July 16, 2013.
   
The saying became popular in 2016. “If we shouldn’t eat at night, why is there a light in the fridge? Anonymous” was posted on Twitter by johndria91 on September 10, 2016.
 
 
Twitter
Natural Hormone Solutions
@robinanielsen
If you aren’t supposed to eat at night, why is there a light in the ‘fridge? Healthy Midnight Snacks http://ow.ly/RBw
12:30 AM · Mar 13, 2009·Twitter Web Client
 
Twitter
Saran Limtrakul
@ranzilla
If we’re not supposed to eat at night, so why is there a light in the fridge?
8:24 PM · Nov 15, 2010·ÜberSocialOrig
 
Twitter
lee Honeybee
@leahmadd_
If we shouldn’t eat at night, then why is there a light in the fridge?
8:17 PM · Aug 16, 2011·Twitter for iPhone
   
Twitter
Nathan
@nkemp31
If you shouldn’t eat at night then why is there a light in the fridge ?
6:40 AM · Apr 3, 2012·Twitter for iPhone
   
Twitter
Craig Hopkins
@Hopkins_Craig
If we shouldn’t eat at night why is there a light in the fridge?
8:26 PM · Jul 16, 2013·Twitter for iPhone
   
Twitter
Destinee Janay Muse⚾
@TheDestineeMuse
If we shouldn’t eat at night, why is there a light in the fridge?
12:47 AM · Apr 12, 2016·Twitter for iPhone
   
Twitter
johndria91
@johndriakn91
If we shouldn’t eat at night, why is there a light in the fridge? Anonymous - #PushAwardsKathNiels
3:13 AM · Sep 10, 2016·TweetDeck
 
Google Books
An Introduction to the Psychology of Humor
By Janet M. Gibson
New York, NY: Routledge
2019
Pg. 66:
If we shouldn’t eat at night, why do they put a light in the fridge?
 
Google Books
Reader’s Digest Fun Jokes for Funny Kids
Edited by Reader’s Digest
New York, NY: Simon and Schuster
2019
Pg. ?:
If we shouldn’t eat at night, why do they put a light in the fridge?
 
Google Books
Smashing Grammar:
A guide to improving your writing skills and avoiding common mistakes
By Craig Shrives
London, UK: Octopus Books
2019
Pg. ?:
If we shouldn’t eat at night, why’s there a light in the fridge?