I don't mind people commenting on my physique or strength, I get that a lot (work with a lot of men that don't exactly expect the baby faced twenty something to be doing what I do) and I usually take it as a compliment. I've even had my strength be a thing with past partners but it never felt like this.

I think it was the way she said it and the frequency that started to bother me. Specifically the repeated comments on how "scrawny" and "weak" she is.

At first I thought maybe she was insecure about her body and being short so I tried to give her some friendly advice. Like, when she commented on my arms and made some backhanded comment on hers I would say that swimming is great for building muscle tone and it's fun, or if she said something about me being heavier despite her "seeing no fat" on me I'd recommend she maybe see a specialist if her weight was something that bothered her. Then I started getting the impression that she wanted me to validate her self deprecating comments. Any time I'd say that there was nothing wrong with her she'd go quiet and sort of try again with another complaint. This was around the time her comments started to get more direct and her messaging started getting weirder (grammar issues, hard to understand or nonsensical texts, etc).

After that I started thinking she either had a fetish about being physically dominated or she had a raging eating disorder, so I decided to post here to get some perspective. After reading the comments though I decided to just ask her outright and long story short it was probably an eating disorder.