In my experience, women having a fetish for fattening guys up is relatively common considering how rare fetishes are in general, and that women are usually less likely to have intense fetishes in the first place. Or at least less likely to admit to it in studies. It's pretty easy to think of societal reasons for why this one might develop more often.
Feederism also pairs well with power dynamics in either direction, with a bossy spoiled feedee being served by their eager hardworking feeder, or a dominant feeder stuffing their feedee to increasingly helpless and dependent sizes. Both parties could even view their dynamic through opposite lenses with that.