Fiancé (29f) says she's not going to consider marriage until she loses weight. I'm (27m) worried that she's developing an eating disorder. How should I approach this?

My fiancé has been casually mentioning that she wants to lose weight since before the proposal. She's always talked about her desire to get to a lower weight and how it would make her feel better.<br><br>Recently though, she's stopped mentioning that she wants to lose weight, and instead she's saying that she won't consider marriage until she loses weight. She's been measuring her waist and documenting it, and she's started waking up at 5am *every day* to run. I know it's because of what I've lifted from her reddit posts, where she's admitting to resenting me for being so much skinnier than her. Apparently I'm the fat one from her perspective because I'm not 6' and I'm not skinny enough to see my ribs.<br><br>I'm worried that she's developing an eating disorder. She's been skipping meals, restricting herself to fruits and veggies, and her appetites decreasing. I've also caught her purging once, and she denied it by telling me she had a stomach virus. The reddit post made it clear she was lying.<br><br>I don't know how to approach this. I love her and I don't want her to develop an eating disorder. I also don't want to do anything that would *make* her develop an eating disorder.<br><br>How should I approach this?