Build your audience first with free stories. You can always work on outlines and drafts for future premium stories and release them once you have a large enough following.

Build a social media presence outside of FF and post previews of your work. I like Tumblr because you can gain popularity pretty quickly just replugging things you like and posting your random feedist thoughts as well!

Once you feel like you have a loyal audience, it's time to offer some premium content!

I believe in you!

OK, so...that was not what I expected.

I'm with L&N on this one; I'm not comfortable with a child protagonist at the center of a sabotage plot.

Like others have said, FF has a policy of no underage characters involved in gaining, but it sounds like you have a story here that, while about a fat protagonist, is more about her life and times in the sense of a regular novel rather than a kinky one. Have you considered pursuing traditional publishing?

Speaking of fat superheroes, Starlight from The Boys. After all she's been through, from her fatphobic pageant mom to the exploitation of Vought, I feel like she deserves to just let go and get fat while Hughie spoils her.

Probably my biggest comfy fantasy is having a feeder/feedee picnic outdoors, with a basket full of all their favorites, maybe some wine, compete with talking, joking and cuddling on the blanket out in the outdoors.

For solo ideas: I'm a feeder not a feedee, but even I like this: pamper yourself with snacks in the bath. I used to do this when I worked mornings, I'd just grab my breakfast and eat it in the bathtub, and it was usually something basic like a poptart or a toaster waffle, and I'd do it for time economy rather than enjoyment, but I did enjoy it. I would imagine myself somewhere fancier, with waitstaff or something to bring me my breakfast in the bath instead of the run-down apartment I actually live in, and sometimes...sometimes that got me through the fkin day.

This is more of a concept than a story. And while the concept is common, it's up to you as the author to string the parts together and execute it well. When approaching this project, ask yourself:

-What is the catalyst to your protagonist's weight gain? Does it start accidental and become something she enjoys? Or maybe she sees other women enjoying their indulgent lifestyles and intentionally decides to give it a try?

-How does the boyfriend factor into this? How do they meet? What is their initial dynamic, and will that change?

-What conflicts potentially await your protagonist and her love interest, and how can they be turned into compelling scenes?

Ray Bradbury. I'd love to see where that would go, both in speculative elements and social commentary.

Seconding the advice above, instead of trying to binge in one sitting, eat smaller snacks throughout the day. Keep snacks in easy reach and just eat one whenever you're hungry or bored. Carb and fat-laden snacks like crackers, cheese cubes, and nits should help you add calories but not fill you up to the point of nausea. Also don't underestimate the fattening power of stereotypically "healthy" food! A salad with crispy bacon bits and a satisfying amount of dressing, or vegetables dressed in cheese and gravy or sauce, can be as caloric as any burger. Plus it helps your regularity, which will help you fit more in your stomach if you do decide to "overdo" it.

(Sorry if that's gross, just stating facts.)

I mean, some feedists are specifically here for the stuffing, bloating, pregnancy, and general belly kink, even if they might not be into gaining or fattening. Couldn't be me though, I lovr fat. Both in a sexy way and in a cuddle my husband and grabby-hands squeeze all his soft parts while I'm going to sleep way.

Have you had an allergy test done? If it's something you can afford at the doctor's I'd suggest looking into it. Tons of people have intolerances or allergies to foods that others can digest effortlessly and never even think about, even something as simple as dairy or eggs.