I'd be struggling to tell what got me *into* the fetish or when I realised I was *into* the kink (chicken and egg stuff, I know) it was probably some mix of Weight Gain/Fat episodes on kids cartoons or other shows.
To be quick, I have a few ideas of media that might have triggered me.
I think Futurama's The Sting had a short section of people expanding to exploding in a dream sequence (it wasn't really fat-related expansion, but it was expansion related, so maybe).
Total Drama Island and the other series had some scenes where the contestants overate and had potbellies, and while it looked silly, might have been soemthing there too.
I remember once watching a Timon and Pumba episode which had the 'fattened up by villans to be secretly eaten' tropes that didn't turn into a vore fetish (no disrespect to people into it, but not my thing), but might have influenced the weight gain/struffing stuff.
and *maybe* seeing Shallow Hal on a TV rerun might have been something too, even if the fat suit in that movie does look pretty poor even for the time.