I'm trying to find a short science fiction story

[catmandu57]

that I read over twenty years ago in a collection of short stories, probably from the sixties, I can't remember the year or title, but it was one of the funniest pieces I've ever read.

A short synopsis:
There were three main characters, an enormously huge fat woman, who hated being fat, hated life, was mean and bitter and a member of the space corps.
A berserker robot whose mission was to roam the universe destroying planets and civilizations.
A loner superhero.
Did I mention that this story was a love triangle?
Anyway, this enormously huge fat woman was always being made fun of and picked on, consequently, this made her very mean and she would attack anyone who looked cross eyed at her.
So, anyway she's in the space corp and the ship she was on crashed into a planet of immortals, killing everyone but her.
These immortals were all skinny and had never seen a fat person in all their long life, they immediately fell in love with this woman and bestowed the gift of immortality upon her, while she was unconscience.
When she woke up and discovered what they had done she wasn't very happy, now, somewhere the berserker and the superhero both meet and fall in love with her, and have a battle royal over who gets to be with her.
I'd give the ending away, but, I've forgotten it.
That's about all I can tell you, it was in a collection of short stories, and in those days I lived in a haze, if anybody recognizes this I'd love to know who wrote it and where I might find it again.

[Enraged_Ape]

1. You've stumped me

Do you remember any of the other stories in this book?

[catmandu57]

2. Nope

All I remember is that it was in a collection of short stories, something like the best of the year.

[okasha]

3. Fred Saberhagen's Berserker

series featured the kind of robot you're talking about. Maybe that would be a place to start looking.

Okasha