Most fat-phobic episode of Catfish?
My vote: Harold and Armani. Not only does Angel Haze make at least two snide comments about a woman weighing 200 pounds (the horror!), but Nev essentially dehumanizes the catfish (most likely at that point knowing it was probably going to be Tamela) when he says "now we don't know WHAT is coming out of that house".
I don't fault someone who has been catfished for not being attracted to an overweight catfish, but the hosts should do better.