General

Honestly I'm a bit weird here. I'm an Aromantic Asexual, so I'm not the average FA. However I've also always found fat very aestheticly pleasing. To that end I knew since I was little I wanted to be very fat. My parents were fat, their friends were even fatter, most my friends parents were fat. How could I not like it? Admittedly I wanted to be fatter then them (and I've almost reached that point) so my initial goal was very big.
Additionally confidence in your look is key to looking good. Someone who has the body they decided to have absolutely own that. Doesn't matter if you decided to be a body builder, be built like a bean bag chair, or just own the dadbod, if it's how you want to look then you'll look good.
So I decided I wanted to be fat, back when 200 sounded huge. I wasn't looking for any kind of relationship, so I labeled myself a gainer and haven't really looked back. My goal numbers have shifted over the years, but I'm still striving for my big apron belly.

I was starved when I was younger and fed a lot of poisons from a schizophrenic mom so now i learned i like food and the taste of food.

Y’know, I think about this a lot too and I think you nailed it at least as far as I’m concerned.

I always had a “weight problem”, dieting and exercising it away. I wanted to get the (natural) bodybuilder physique. I never achieved it though I got in pretty good shape running, mountain biking and weight lifting.

I worked at a school as the IT admin. where there was a custodian named Hector. He was the sweetest politest guy you could meet.. and he was fat. I thought he was attractive as hell, though I wasn’t into fat guys then. I still maintained my dislike and fear of getting/being fat. But I fantasized about him... I still think about him 30 years later.

I discovered Xtube and kept stumbling on the fat guy videos. It was a guilty pleasure to see guys that I thought were really obese... which it turns out that relatively speaking they weren’t... turned me on.

When I saw I wasn’t going to achieve the body image and goals I was going for, realizing that I’m basically lazy and it was more work than I wanted to continue with, I let go and started gaining. I let the historically fat guy in me out of his cage. I’ve wavered over gaining, maintaining or losing. I unintentionally lost 35 lbs last year (I moved, doing most of the work myself). I recently put back 5 lbs and am trying to get back up somewhat. I’m 215 at 5’6” but don’t know if I’ll ever hit 245 again, much less the 260-270 I hoped.

For someone who was fat phobic to the nth degree it’s amazing how much I like being fat, and how I’m attracted to fat guys. And it seems I keep raising the bar.

Probably my attraction to bigger women

For what I know, it's a mix of genetics (ie stimuli that arouses a person) and personal history, being that childhood has the biggest effect on it. I've actually looked up research about feederism and being attracted to fat people but I haven't found anything, it was a very brief search tho.
I remember that as a kid I already used to play pretend of being fat ahahah.

I'm actually stud psychology, maybe I'll do my master's thesis on the topic

I'm new to feederism, but various pieces have been coming together for a long time, which collectively made it a passion for me.

I've always found large women's breasts attractive, and, when younger, mine were abnormally small (long story), before pregnancies when they grew and stayed larger. I also like big rounded or fat, squishy bottoms. I read about primitive societies who fatten their women up on healthy food for 6 months before trying to get pregnant, and it checked out scientifically. (That's probably why ancient fertility dolls look like they do.) I'd always been lean without dieting, and an athlete. But I tried hard to gain and maintain 15 pounds before pregnancy, and then ate all I wanted during pregnancy, for another 35 pounds. I loved being pregnant, so relaxed, slept amazingly well, and was super creative. And of course I ate, ate, ate during this time, which is probably part of why. I discovered I LOVED pregnant sex because of all the fullness. I felt so womanly, so full and big. For me, this is what stuffing or bloating replicates. I still have a tipped uterus, so I bloat protruding and rounded like I am pregnant (so much that I need different sizes sometimes), and that can be erotic, holding and feeling around my rounded belly.

And an odd thing: when I was just starting to develop hormones and before anybody told me about the facts of life, which in any case were not shared too much with girls back then, I discovered self-pleasuring in the pressed crossed legs pose of having to go, but holding it. So I shouldn't be too surprised that later in life I came to love filling myself with fluid and holding it during sex. The strong pressure is very arousing and pleasing, and of course feels more full. Several fantasies and kinks all have to do with being filled up, bloated in some way, so there is that in common. Maybe because the opposite was encouraged growing up, though I've always been a good and eager eater.

I ran across feeder videos and they were an amazing turn-on. I've been looking into it since for a few months. Though a prior medical miscommunication, I ended up on too high dose of hydrocortisone (cortisol, the stress hormone), which put on a pad of belly fat, and heavier weight in general, for too long. I gained about 30 pounds, and stayed just at the overweight/obese BMI line for 3 years.

A couple of weeks ago, I started deliberately gaining, mostly with heavy cream and eating treats if I want. Hello, pudding and Boston Cream donuts. Already I have noticable soft new fat, and it feels so soft and nice! Silky. And many small things got better that I did not even know apparently needed some fat. Plus I am much more mellow and happy. I love this feeling! So I am going on...

Planning to eat to target bigger curves filled mostly with healthier, soft, subcutaneous fat. I hope to have a handful or more wherever. I like imagining how the extra curves might look -- so different for me -- and how it might feel to carry that extra weight on the various parts of my body. To feel its pull. Yes, I have a vivid imagination.

In recent years, I have also discovered my submissive nature, so opposite from my daily life. So being fed by a feeder, with the surprise of not knowing what he would bring/make, what I would eat, how much I could eat, being expected to eat so much, is definitely a desire.. Wondering what it will do to my body, how much and how fast. How big could I get if I want? And knowing it's a turn on for him and he wants to see and feel my bloated belly after eating, hands on, its fullness, and feel my soft fat as it grows in various places, is pretty darn exciting.

I guess all the pieces just came together.

I think I eroticize fear and humiliation, and I only really had one fat relative growing up, who is still my favorite family member, but who was always trying to get thin. All the rest of my family was always afraid of being fat and dieted incessantly. I started fantasizing about being shamed for my weight, and it all kind of expanded from there.

Now my boyfriend and play with each other's bellies with admiration. Someday I want to hire a pro to humiliate me but in the meantime I can enjoy the loving, tender side of this fetish.

I think for me it ended up as a sort of evolution of another fetish. When I was younger in my teens I realized I had a pregnancy fetish. But I also eventually realized I don't want kids. Kinda makes it hard to have a pregnancy fetish that way. (I still find pregnant bellies absolutely sexy) so eventually I started liking plus sized women. Not sure if it's because that's a way for them to have a permanent big belly or what. But that's what I believe brought me to it. Then it grew from there. The feeling of the soft curves. The growing. I guess like everything else my interests evolved.