“Yo mama is so fat, she went out in high heels and came back in flip flops”

A popular “yo mama” insult “fat joke” is:
 
“Yo mama is so fat, she went out in high heels and came back in flip flops.”
 
The joke has been cited in print since at least 1993.
       
 
7 March 1993, Battle Creek (MI) Enquirer, “Playin’ the dozens hones a bitter wit” by S. Renee Mitchell, pg. 14A, col. 4:
“Your momma’s so fat, she left in the morning with high heels and came back home with flip-flops.
 
Google Groups: k12.chat.senior
Ya’ Mama Jokes
Sally Thurer (Winsor 95)
11/21/94
(...)
Ya’ Mama’s so fat, se went out in high heels and came back in flip-flops
 
Google Groups: rec.humor
Canonical List of Yo Momma jokes
Price Charles
12/4/94
(...)
Yo momma so fat she left the house in high heels and when she came back she had on flip flops.
       
Google Books
A Prairie Home Companion
Pretty Good Joke Book
By Brian Becker
Minneapolis, MN: HighBridge
2003
Pg. 73:
Yo’ mama is so fat, she left the house in high heels and when she came back, she had on flip-flops.
 
Google Books
This Raging Light
By Estelle Laure
New York, NY: Houghton Mifflin Harcourt Publishing Company
2015
Pg. 8:
“Your mama’s so fat, she left the house in high heels and came back in flip-flops.”
   
Google Books
The Best Yo Mama Jokes Of All Time
By Jack Jokes
PeteyRF Creative
2016
Pg. ?:
YO MOMMA SO FAT!
she left the house in high heels and when she came back she had on flip flops!
 
Reddit—Jokes
Yo mama’s so fat
submitted September 10, 2017 by owenthomas1989
she went out in high heels and came back in flip flops