Hah, I actually just made a dumb throwaway. I lurk here... a lot... but this is the first post I needed to reply to.

Anyhow, you've gotten a lot of really great advice here already and I can't really add much to it. I will say that I keep seeing you mention "several men" pming you because they don't want to kill their karma (cause imaginary internet points are so. damn. important), but that they agree with you. Unless these guys somehow outnumber the vast majority of replies here, you're throwing yourself into the very tiny pool of one specific type of people when there's an entire friggin ocean out there, and you're only doing it because it's familiar. Thinking outside of what's known is hard, I get that, honestly I do. Seeing your comments about how some of the women here must be from a foreign planet/land to have had a different experience really makes it out like you don't really want to believe there's that whole ocean out there. That's therapy talk, though and I am most definitely not a therapist. Point is, everyone has their preferences, but one group isn't the whole of it. Some are very specific, some are more general. I'm also not saying you shouldn't do what makes you happy. By all means, get healthy! Lose that weight! But don't do it for some imagined person that doesn't even exist. Do it for yourself.

This is what I wanted to say, though, and why I made this account. My own experience, which isn't dissimilar from yours and is different from many of the people who have responded here.
I'm overweight, have been my whole life. I was picked on, teased, bullied, I was the "fat friend", etc. I have made people turn off the lights or let me leave clothes on so that I could try and hide my body. It's awful, it makes me sad and lonely, and even after years of therapy and working on myself, I still have some issues to work on. I was downright grateful when people deigned to grace me with their attention (sexual or not), and I put up with a lot of crappy relationships/FWB/who-knows-what because I thought it was the best I could get being the "fat chick".

Now, those were my vanilla relationships, the BDSM relationships I've had... They were the only times in my life that I felt normal and just as good as everyone else. It wasn't because my Dom thought my curves were sexy as hell or was into heavier women. It also wasn't because I discovered some secret inner anything that suddenly gave me the confidence to whip my shirt off in front of anyone. It was because I could achieve the things my Dom asked of me, that I could accomplish (with guidance) anything that they put in front of me because they set me up to do so. It wasn't about how flabby my belly was or how jiggly my butt was, but that I could do these things. Demanding impossible things or things that a person just can't give is only setting them up for failure (ie: look "perfect" constantly or you're nothing to me) and they're giving no regard for the actual person. These weren't always sexual relationships either, and when it was I wasn't always their "ideal" specimen but they were attracted enough to go for me, but I see in other comments you weren't even really aware that sex wasn't always a part of things. The point, I guess, is that I made them happy/proud by doing exactly what they said they wanted of me, and that was what did it for me.
Going around assuming a Dom wants my ass to be pert and tight even though they never once even mentioned it to me, after they told me they do in fact want me to press their pants so perfectly straight that you could use it for a level, is just bad service. Same for any of the other comparisons you made. You're not really a sub at that point, IMO, because you're going against what they actually wanted, said they wanted, and putting all of your own demands on them instead.

This got long, sorry! Here's the tl;dr, though: You're putting your fears/feeling of inferiority and self-consciousness on a wide variety of people, and that's not fair to you or them. Do what makes you happy, not what you think would make another person happy, because that route is a long, dark rabbit hole. Get a good therapist, work on you, lose that weight because you want to feel good about yourself. If you want a Dom that's into that sort of thing, I'm sure you could find one, just make sure they're a decent human being first.