I really wonder what made Ruby want to lose weight initially, what triggered her potential ED? She used to be at a healthy weight and she seemed to enjoy a diversity of foods, I rewatched some of her vlogs in her first year at Uni and although she was already restricting (going vegan), she still bought a lot of food and ate decent portions. She didn't seem obsessed with tiny portions or with the same boring food like peas or yogurt bowl with a quarter of a banana...
TW: ED's
This is all speculation and I can only speak from my experience (I suffered from an ED for over 10 years) and because I see a lot of my past self in Ruby. But here are just some potential reasons why I believe it manifested the way it did for her...
1. Control: ED's aren't always about food but more so about the control it gives you. The pandemic definitely didn't help and with Ruby being away from her childhood home/comfort zone at the time she panicked and resorted to something that would give her some sense of control. I'm not sure if going back home was worse than staying in her uni house. For me being away from friends and family fueled my ed more because I didn't have to worry about other people finding out in a way but regardless she still carried on.
2. We all have speculated she might suffer from OCD or have autism which is common in people with ED's. (Also autism in girls/women is often under diagnosis compared to boys/men). This ties in with the amount of pressure she puts on herself to be perfect so maybe she thought that since she already had "perfect" grades she needed to "perfect" something else: in this case her body.
3. I think another part of it comes from her fixation on being a child and not growing up. She doesn't want to be seen as an woman, she wants to be seen as a child/young girl and in order to do that she thinks she needs to remain small and dainty, which again is common in people who suffer from eds. She doesn't want her body to grow up so she's preventing it by starving herself (when in reality it's just going make her age quicker). I think another things that ties into this is that she wants to be a fictional/historical character. And all the characters/figures she sets out to be are either skinny (think Anne from Anne with an E) or a starving Victorian. She purposely eat like these characters and figures because she wants to emulate them.
4. Lastly, maybe she did want to lose a bit of weight in general. Some ed's do start off as harmless as that but then they spiral, take over and are hard to come back from. She was never overweight. She was healthy and athletic given her gymnastics background. So maybe she did want to lose a bit of weight at the beginning but it turned into something worse.
Again this is all speculation. But I see a lot of my old ed behaviors and tendencies in Ruby. I was a similar "perfectionist" student, I'm autistic and I'm a history nerd (I studied history in undergrad and post grad) so I even somewhat get the fasciation and desire to emulated the past as Ruby has done. To me it's almost like seeing a past version of myself and noticing the warning signs as they are happening to her. I really hope she gets help soon.