Some brave, brave taxonomist, or perhaps there's a full on guntologist somewhere, has developed a grading system for your convenience.
She doesn't have to chase her far. She just has to get close enough that the kid falls into her gravity well. Eventually the kid will probably work up enough steam to reach escape velocity but when she slows back down mom just has to get close enough and she'll fall back into orbit. Even if she miscalculates and the kid burns in, the landing will be nicely padded. It's parenting by Kepler.
I take a few months off from the intarwebs and I miss all kinds of shit. A chick I played with a few times in the late 90's is still around the scene where I live occasionally - She mostly only does shit on IRC and chat channels now. She was a curvy chick when I was dating her and I broke it off after half a dozen dates because she was crazy then. I have no idea what she weighs now - but I've seen her get into an 8 person spa with one other person at a party, and the other person had to get out because there wasn't room. Pause for a moment to dwell on that mental image if you will. In case you were wondering, She was naked at the time. She had gastric band surgery. Her husband at the time put KFC in the blender so she could eat it a couple of times that I know of. Needless to say, it hasn't done shit for her weight. Largely this sort of kink is just not in my wheel house. I haven't spoken more then a polite greeting in passing to the chick in like 12 years - and she wasn't ludicrous then. I've talked more to the guy who did the KFC in a blender thing, but not about the motivations for growing a behemoth. My observation is that the people who get into this are usually overweight to begin with and have body image issues. When you've got a kind of fragile self image to begin with and someone suddenly worships your ass as the hottest thing they've ever seen, or puts up pictures on the internet and you get dozens or hundreds of people telling you that you are the most beautiful thing they've ever seen - it's gotta be seductive as hell. Everything that you've ever hated about yourself suddenly becomes why you're hot. So I kind of get how fat people get sucked into actively trying to get fatter. I mean on some intellectual level, taken purely in the abstract, I can follow the motivation through as a concept. Eww. but I kind of get it. The bit I don't understand is the guys who are into it. You can't fuck a 500lb woman. You certainly can't fuck a thousand pound woman. If the discovery special I watched about incredibly fat people is taken at face value - thigh skin gets leathery and ends up more than an inch thick and feels like elephant hide on very fat people. My understanding from people I've talked to online is that for the most part - they either jerk off or get oral sex occasionally but anything else is off the table, and there's a requirement for hours a day of care to the incredibly fat partner. Some feeder/fat admirer types get off on the fact that their partner is completely dependant on them. Sometimes in a really creepy domestic abuser sort of way, where the thrill is that the fatty can't escape and can't ever leave them. Sometimes in a it'd be sweet if it wasn't so fucking unhealthy for the partner, where the thing they get off on is all warm and fuzzy and about being needed and being able to help.
Putting this thing up my ass. Yes, I actually paid forty dollars for it at a sex shop. I gave up before I hurt myself. 100% true story.