When you've grown up in this era you can tell the fatties. I can even tell assholes from a few lines of convo. I guess it's like an "online sense"? You can tell a bunch by the way someone carries themselves in real life and you can tell by seeing what they choose or choose not to say/show.  I can pretty much insta tell a fatty. I'm bi so I browse both. Guys seem less catfishy but much more deluded in trying pass off fat as strong.