Weight is not a good measure for this. Compare Dankii and Boberry for example, just to take two names you can easily find public pictures of. Dankii is below 400 pounds but looks as fat or maybe even fatter than Boberry who is (again) above 600, because of the height difference and having more of her weight in her belly. And even compensating for height, people can have different body types, different fitness levels, muscle, etc. The effects of her size on the body, what it can do and where it can or cannot fit, would be a better criteria. I would define the borders between the categories more in the terms of how her size affects her everyday life, and how it compares to sizes smaller or bigger.

I would say BBW starts where it starts getting impossible to hide that she's overweight, even with clever clothing choices and posture. But still a very much livable size without significant adjustments and without drawing attention.

I would consider the threshold between BBW and SSBBW to be where one starts getting bigger than most things are designed for. Chairs, cars, seats, booths becoming too small to fit into comfortably (or at all). Certain body positions and movements starts becoming very difficult or impossible (tying shoelaces, walking up more than a single flight of stairs without having to stop, etc.).

I would consider someone a SSBBW from a size where one has to start making significant adjustments in daily routines because things start not being designed for that size. These routines are still possible, but only with difficulties. Where every physical activity is still possible, even if only for very short periods of time. A size which starts seriously affecting what one can or cannot do, but still not as big to make most activities impossible.

And when even very basic daily routines become impossible or almost impossible without help, would I use the term USSBBW.

In fantasy, yes, all the way up to the point where standing up requires a lot of effort and preparation, and several tries.

In reality, no. Well, maybe if she was athletic and got moderately overweight, and overestimates her capabilities and ends up winded, yes, that can be hot in real life too, so maybe, a little.

I'm more of a Boberry-fan, liking someone to be as mobile as possible for her weight. Or the other side of it, to exercise and be healthy, to be able to be the most fat for the same amount of desired mobility.

Boberry is one of the biggest models who is surprisingly strong and agile for her size, and works out regularly.

You know what's asinine? Your unwarranted ASSUMPTIONS that I don't consider them as human beings. Does it make you feel better or elevated to constantly accuse others of this?

Is this degrading, patronizing, and accusatory tone really necessary? All I asked for was some personal experience about what to expect, and what someone who did not experience being with someone of that size might not realize, and it was hypothetical anyway. And of course I'm not 5 years old and I know that a date is not a pet and I should be communicating with her, duuuh.

And all I got was accusations, personal attacks, and wild assumptions. This community is really getting toxic by the day

Yeah, I know, that's also in the obvious category. However, in many cases very obese women don't really want to talk about their weight (not everyone is a fetishist, and even if so, not everyone is open or bold), especially in the beginning, so asking her too direct questions at the beginning might not be the best, and she might not say anything about how to accommodate her, right at the beginning.

What I'm most looking for in the answers from people with experience, is something like "I know this, but I wish I had known this sooner".

As a guy who prefers "moderately large" ladies the most (by FA standards at least), in the range of 200-300 pounds, I still can find very thin and much larger women attractive, as style and personality matters me more than just raw weight. However, my dating experience is only with thin, or with at most about 300 pounds girls.

Lately I've been fascinated with the thought of dating a woman who is much larger than the size range I've been used to, even 500 lbs or more. I've never met someone this big in real life, there aren't really many 300+ lbs in my area, but from online photos and videos I learned that it is possible for me to find even a woman above 500 lbs super attractive.

However, due to my lack of experience with sizes this big, I'm interested in some advice. How should I prepare, what should I look out for, if it so happens that I find someone in the 450-500 lbs or higher category, so I don't cause embarrassment for myself or for her? The more obscure and unexpected the advice, the better. I'm not a complete idiot, so of course I know not to invite her to a difficult hike, or to any activity which would be tiring for her or too difficult for her to navigate. So I'm looking for advice from those who are of that size or have dated someone of that size, and know what people inexperienced with such sizes don't expect.

There are many women who prefer to be overweight (or at least accept it because they love eating way too much), and this community is full with them.

And there is a community of women who love having hair as long as possible, usually below knee length, and some even more than floor length. (of course, they also have to have lucky genes for this, but so is it for feederism if someone wants to go to extreme sizes before being stopped by debilitating health problems).

But I don't really see the two combined. Two examples come to mind, Mochii and Dankii, who are significantly fat, and have about hip-length hair. But I haven't seen any other examples, nor any other BBWs or SSBBWs with longer hair than that.

Sadly this is becoming more and more common in real life too. Yes, it can happen that someone loses interest after a few dates. Or that things change. But it should be common courtesy to at least tell the other that sorry, things are not working out, and say goodbye. If they don't even want to spend half a minute sending such a message, it just shows how self-centered they are and how little respect they have for others.

Not really, at least not for me now anyways, I've had exposure for long enough to know myself. At the same time I can find someone at 400+ pounds that it would be awesome if she gained some more, and at the same time someone approaching 300 that it would be better if she stopped gaining or maybe even lost a little.