It's a good overview! Might be cool to have some quotes from community members in there, or maybe in a companion article.
If this is article is supposed to be an introduction to feedism, I have some concern over some word choice and definitions.
1) feedism vs. feederism
For example, the move in the community to refer to the kink as "feedism" instead of "feederism" was a wise one, as it's the more inclusive term. I don't claim to be on every corner of the internet, but I see members of the community use "feedism" far more commonly these days. I also think "feederism" reflects the sensationalist narratives run by outside media. It kind of suggests that the kink is entirely driven by feeder's desires, ya know? Rather than feedees being full, eager, autonomous participants.
So I prefer to see the kink referred ot as "feedism" throughout the body of the article, possibly mentioning "feederism" in the gloassary at the end. Something like "Feederism: you may have seen this kink referred to as feedism, which used to be the common term."
2) Glossary terms
While seeking a perfect definition is futile, the terms as they're defined here seem narrower than--and in some cases, not accurate to--the ways I've seen community members actually use them over the years.
2.1 feedee--there are plenty of people who identify as feedees (including me) without feeders. So I think the bit about "with the assistance of a feeder" should be removed.
2.2 feeder--as with feedee, there are plenty of people who identify as feeders but for whom directly, literally feeding their partner is not of much importance. So maybe something like "A feeder is someone who enjoys helping their partner put on weight, wether through feeding them directly, cooking for them, encouraging them, etc.
2.3 feeder/feedee vs. gainer/encourager--I've seen lots of people attempt to differentiate these over the years, with little consistency. This seems like one of those instances where people try to come up with different definitions simply because there are two different words, when in reality, they're used to mean pretty much the same thing. [Much like colloquial uses of "kink", "fetish", and "paraphilia"]
IME, the biggest determinant of which set of labels someone uses is not which behaviors/activities they take part in, rather, sexual orientation and which community somone became involved with. Gay men (and some bi men) use gainer/encourager, and the rest of use use feedee/feeder. There's some crossover between who uses which terms of course (IMO, moreso in the last few years than in the last ~10+ before that), but that's the most consistent difference.
If anyone is skeptical that this is the real difference, I recommend using search engines to look for "feedee porn" and "gainer porn"
What does this mean for the glossary? Maybe something like:
"Gainer: a term similar to feedee, but more commonly used by gay men"
"Encourager: a term similar to feeder, but more commonly used by gay men"