Eugenia is old enough to have been affected by 2000's diet culture on top of her obsessional disorder.
****A history lesson and sperging****
To be a size "0" was the hot girl size in the late 2000's especially. Many people think it was in the early 2000's but that's actually not true, being slim and curvy and having the J-Lo butt was a thing as with having a Beyonce type body in the early 2000's much more than looking stick thin. It was only in the late 2000's that the anorexia craze and this very niche pant size soared in popularity. Starting around 2007 in my opinion. In 2006 actresses were already developing anorexia at a startling pace, Hollywood women were becoming skeletons but it took another year to reach the general public. Eugenia would have been 13-15 during this time period and I'm absolutely positive she was sucked in.
I think I've said it before, but Ozempic-esque 2020's skinny these days is nowhere near late 2000's/early 2010's thin-ness. There was Eugenia type body's on the runway, on Myspace and in Hollywood. It was so bad. There was quite a few deaths I believe around this time in the modeling industry.
2000s DIET CULTURE
I remember this culture so badly. I was super jealous because my friend was in a 00 instead of a regular 0 (it was proportionate to her) . This was the time of the low waist hip. I witnessed girls being made fun of for being a size now that a modern American wouldn't blink and eye at being "fat" and would defense squad her. I remember having to be calmed and calming girls down who looked like pics below because they were not 2-00 size. Would you like to see these FAT girls?
Behold! The first "plus size" model. A whopping size 8 for Victoria's Secret. This was in the 2010s. Yes, it took that long. Yes, I remember girls freaking out about their THIGHS TOUCHING meaning they were fat. When thigh gap was
everything.
Wanna see a REALLY fat girl?
Now Behold! The FAT FAT FAT Calvin Klein model in 2010 who was a DOUBLE DIGET size 10. You would never be caught
dead in a bikini because YOU HAVE A STOMACH. Plus size stores sold 10s and 12s in this era too. (Sometimes even 8s.)
For teen girls, you might as well have a death fats thread if you weren't in the holy sizes of 00-2 (maybe a 4 period bloated).
Would you like to see what we saw on TV and in magazines?
This was popstar Christina Agulera maybe 2003. This was how you had to look. This was AVERAGE in the minds of the 00s public. I remember the media throwing a fucking FIT when the ribs-showing woman gained 15lbs and looked like this in later 00's:
She's a girl who has fluctuated in weight but arguably has it in all the right places. This isn't Lizzo. This is a size that today is deemed as sexy and thin today where it was FAT in yesteryear.
The alt girl culture around the time there also peaked this. Her scene girl looks LOVED the waifish childish thin figure. Granted, some women are just built like this and if you grow up in an era where your natural figure is deemed as beautiful you win a genetic lottery of sorts.
(Kiki Kannibal circa 2000s)
Girls who were even large breasted or hipped but otherwise thin got the "fat" thing and weren't accepted. Girls who had a "normal" weight were NOT accepted. Take Kiki's sister Dakota Rose
(who is mostly farmed on lolcow and was one of the first users of jeet fake engagement for fame)
She's pretty but average. She shooped herself to the right size because left was FAT. Granted, she's in Japan here so this is still FAT for Japanese standards.
She was made fun of on Myspace and Pretty Ugly Little Liars (PULL)
incessantly for being FAT at this size because she wasn't taller and 00 skinny like her older sister. I cannot find the picture but there's one she was railed on for the size of her thighs that I remember as FAT in my 00s mind, but it was likely average teen girl size in retrospect.
This is what Eugenia was exposed to and absorbed. While I know a lot of women who went through disordered eating behavior for a short time (crash diets), some ended up Eugenias and were praised for looking good.
There is also one other fact of her personality that I cannot stress enough. The Makeup.
2000s Makeup Culture 
If you're a girl and you're of middle school age like she was, you already have issues about your appearance. Teen girls are
mean. Having a single skin roll when you bend over was enough to be FAT and not wearing makeup was enough to be UGLY. I need to emphasize this showing you some of the shows that were allowed at the time to give an idea of public perception.
Howard Stern had a "miss butterface" contest. And this was what you'd get. Basically a woman without makeup.
Girls who were teens in the 00s basically have this thing where they still cling to makeup as warpaint because if you didn't wear it, you were UGLY. Eugenia embodies this in needing her warpaint on to face the world. It's hard to get girls who were VERY makeup coded in the 00s to quit because this was very engrained in us that if you didn't look like this, then you were UGLY.
Someone put a filter on her. Suddenly? Attractive! Great! Acceptable! This is a level of nitpicking and body hatred that zoomies and gen alphas can never fathom.
-----
Eugenia, and sadly many other girls, NEVER let this shit go. They still look at themselves through 00s funhouse mirrors. They still see FAT and UGLY if you're not wearing makeup and at the "correct size".
That being said, modern women growing up aren't much better off either. It's too fat for one. But again, your girls who would have been "hot" in the 00s are now too skinny and ugly and get called boyish or child-like for having a naturally thin body. Your girls with curly hair and curvy (not fat but really curvy) bodies like Christina Agulera are now worshipped where before you were FAT.
It's never a fair fight. Women live to be perceived. Eugenia is just stuck in the skinniest perception era. We have all seen plastic surgery nightmares of girls who try to fit the idea of beauty of the modern era of curves. There's developing calves cows being weaned who will be this way, I guarantee it.
Unironically loving your body and take care of it is the best thing you can do as a woman lest ye end up a Lich or a Deathfat.
