Acronym; "As Fat As Doggers".
To be at a point where one might be considered to have actually reached 'afad' is near-impossible. It would certainly be a pre-cursor to sudden death.
To be 'afad' or 'nearly afad' is to be a person of almost immeasurable size.
see; Morbidly Obese, Corpulent, Cormorancy
"I need to back off these Akash Curries, I'm almost afad."
The kind of barely-human being you might see waddling round Disneyland Florida, on a Rikki Lake show or occasionally hobbling around Bradford Road in Bolton.