Douglas, I like your piece. The trouble is, it's really a 32-line poem disguised as 16. But maybe the 'supersized' competition subject will let you get away with it.

I thought I'd have another go.

Fat is Good 2

It's the Lardy arses of the Working Classes
That make Great Britain great.
It's the haddock suppers, though we're on our uppers,
That fortify the State.

It's the gamin gutties with their thick chip butties
That prove we're on the ball.
It's the baked bean buyers and the Mars Bar fryers
That keep us walking tall.

So set us in our greasy spoons
To gorge on corned beef hash,
Big sticky buns and macaroons,
Fried sausages and mash.

It's the pendant bellies crammed with jams and jellies
That make us what we are.
It's the sweet tea slurping and the beery burping
That win us the cigar.

I'm thinking Sophie Dahl when she was a size 16. Hubba hubba.

And there's always Hattie Jacques. I don't know what size she was.

Brian;
I hereby dub thee “Poetry Detective”. This began as a fairly close parody of Swift’s original, which is in tetrameter. But, to get the whole narrative, I was actually up to 44 lines! I whittled them down to your stated 32. Then, I recalled my Organic Chemistry lab, where we made monomers of something into dimers of something else. So, using some poetic polymerase, 32 tetrameter lines became 16 octometer lines. While Swift hoped “To split my worship to in twain”, I opted for fusion, rather than fission.
Metrically, this is not strictly kosher. But, as you say, maybe I can slip my supersize lines in on account of the subject.
By the way, my computer is old enough that its spell check underlines “supersize” in a wavy red line.

That's nothing, Douglas. I'm so old that my internal spelling checker keeps trying to change "show" to "shew".

Appropriately and deliciously gross, John. But I started thinking about the third stanza, which diverges from the pattern, and came up with the following, although it doesn't exactly match your rather tricky metre:

On bums like half-moons, we sit in ‘greasy spoons’
To gorge on corned beef hash,
Macaroons, sticky buns, treacle pudding in tons,
Fried sausages and mash.

P.S. On reflection, John, your variant third stanza may be a good idea, so feel free to forget my preceding remarks.

Brian,
In 1950s America, a top-rated TV program was Ed Sullivan's variety show. Ed would begin each episode by saying "We have a really big shew for you tonight" . I suspect that this still lives on in youtube land.
Ed was no fool, by the way. He introduced Elvis and the Beatles to nationwide US audiences.
But, anybody under about 50 does not recall Ed saying shew.

My idea, Brian, was to make it like a song. The third stanza is like that bit in a blues, you know what I mean. I like your stanza though.

Is it a blues I'm talking about? Something to do with songs. Maybe I mean the sort of thing Fred Astaire sings.

John,
I think the songwriting term for what you mention is "bridge". But, I am a babe in the woods about music, and may be wrong ... there are other Spherians far more educated in these matters than I am.