So ages ago when I was a teenager and didn't know what kind of porn I liked, I'd just click around and check out a little of everything. One day, I saw a category on some site labelled "Transformation". That's how I first became exposed to feederism. My takeaway from it, was that the feeder enjoys ruining the other person. You make them more dependent on you, maybe it's a revenge thing, but at no point does the feeder actually want to be fat themselves. You're just ruining someone else's body.  Anyway, that was my takeaway after reading one story, deciding it wasn't for me, and then moving on with my life.