It was several thing's for me,
I already deep dived into vore, thanks to the dark side of YouTube and the glorious Mewtwo/Charizard comic... so that was a thing.
Then during my first relationship my bf always commented that I was too skinny and I heard through one of his friends that he preferred curvy women. I was pretty heartbroken by that but was already into stuffing and ate massive amounts of food, I simply couldn't gain at that age/ activity level.
Later on I gained weight for a brief period when I was 18, I started bulking in the gym and got lots of comments about how thick and juicy I was looking. The attention sure helped and I felt better then ever not only mentally but physically too.
I definitely prefer women looking heavier and guys who got that bulky/fit/fat look.
There's more to it but this is it in general.
2 years