“What do you call someone who can’t stick with a diet?”/“A desserter.”

“Deserter” (a member of the armed forces who deserts) shouldn’t be confused with “desserter” (someone who enjoys desserts), but there are puns. A diet riddle is:
 
Q: What do you call someone who can’t stick with a diet?
A: A desserter.
 
The joke was has been cited in print since at least 2015.
 
“My uncle used to carry a trifle in the army. He was a desserter” is another “desserter” joke.
   
       
Twitter
Cortés Restaurant
@CortesRest
What do you call someone who can’t stick with a diet? A desserter. #Jokes #MondayMotivation #Foodie #Quote
4:15 PM - 20 Apr 2015
   
Twitter
Oh Mexico Restaurant
@ohmexicomiami
What do you call someone who can’t stick with a diet? A desserter. #Jokes #Laughs #Likes #Follow #RT #SOBE
1:02 PM - 21 Apr 2015
       
Twitter 
ION
@ion_nutrition
Well this #joke made us groan and laugh:
Q. What do you call someone who can’t stick with a #diet?
A desserter.
…badum tish
4:49 AM - 27 Nov 2015
 
4 April 2018, Shenzhen (China) Daily, “Jokes of the Week,” pg. ?
Q. What do you call someone who can’t stick with a diet?
A. A desserter.
 
Reddit—Jokes
Q: What do you call someone who can’t stick with a diet?
submitted April 29, 2018 by JquaterReddit
A: A desserter.
 
Twitter
lorraine Jo King
@LahLahBean
#Sillysaturday
What do you call someone who can’t stick with a diet?
A desserter.
4:10 AM - 19 May 2018