@Wiimeiser  
Yes, but she’s still different enough in built to be noticeable, and nopony shares her build, so my point stands. :P

@Scrounge  
Babs is just a little rounder. Hmm… I wonder how an anthro adaption would handle that now, especially unguligrade…

@Background Pony #0D23  
And most mares that aren’t that size are either alicorns or fillies, and most fillies seem to be about the same size as each other too.
 
There are a few with unique proportions: Babs Seed, Mrs. Cake, and perhaps most of all Princess Celestia herself, and there may be the odd category-jumper here and there, like Fleur-de-Lis, who would wear the same size as Cadance or Luna despite being an otherwise normal unicorn, but for the most part ponies are differentiated by coloration, mane style, and cutie mark.
 
How about an alternative?
 
My headcanon is that Rarity categorizes outfits by the race of pony they’re designed for. With unicorns and earth ponies, it’s fairly interchangeable other than hats, but obviously a pegasus outfit would likely need special considerations to make sure its wearer could still fly (or at the very least, they need wing holes). Alicorn outfits, obviously, aren’t designed until there’s already somepony waiting to wear them, as alicorns are so much less common than other breeds of pony, and seem to vary much more in build. Designing for the average unicorn is one thing, but there isn’t really an “average” alicorn.

So that’s why she’s stuck sewing rags in a hick town.

This idea seems rather cute, if confusing.
 
But the problem is that it’s just totally wrong. Being beautiful and ugly is not dependent on weight. That is such a messed up view to have.
 
For example, I’m not ugly because I am fat, I am just fat and ugly.

Well with mares at least over 90% of them are the same size so it’s a non-issue

Ew no that’s just weird

so starbucks?

This is one of the stupidest things I ever heard,if you need to replace abstract measurements with self-favoring words to make yourself feel better you really are pathetic.

If she doesn’t want to use numbers, wouldn’t it be more practical to use letters? That way you could still keep track of increasing size.

I have spoken to the owner of the blog and they might be okay with this, or is working on it themselves, so I will actually leave it be for now.

Hey, this is one of the mods for the tumblr that created this.  
Can whoever posted this please take it down? We were not asked or notified about this post by whoever posted it. We kindly ask that you take this down as we are highly uncomfortable with it being posted here.

But… sizing is only an issue for mass produced clothing no?
 
If Rarity is making custom orders for each customer then she has no need to mention sizes at all since whatever she makes is going to be tailored to their body regardless of how thin or fat they are.

@C8BF (Can’t reply directly for some reason.)
 
I wholeheartedly agree.
 
How big or small someone is does play into objective health outcomes (as B937 said) or how attractive someone is/if they are generally attractive (beauty is not entirely or even mostly subjective).
 
But the issues with the health part isn’t entirely based on weight and proportions (BMI isn’t a great indicator of health, it’s a quick and dirty measure). Most concerns with outright obesity can be helped through proper exercise and diet.
 
And as you said, not being the model for the ideals of beauty is only a small part of a person. Sure, they’re more attractive to look at when you first meet them, but most people in solid relationships or even failed ones can tell you that a lot of other factors about a person can make the sight of an ugly person a pleasant experience or seeing an attractive person nauseating and anxiety-inducing.
 
In practice, this only puts a bandaid over a problem as opposed to starting to address the cultural problem itself.

I don’t imagine Rarity judges clients that have weight problems or eating disorders, which negates the need for a bizarre sizing system.

Measurements aren’t the problem in fashion design.
 
The use of measurements only become questionable, when they are the first thing that is referred to when addressing someone’s worth and giving the impression that having the “correct” measurements are the most valuable part for a human being.

Obesity is not “gorgeous”, it’s a health risk.

She could have honest labels like “starving ghoul” and “elephant”.

“Let’s see… you’re a size extra… extra… EXTRA fabulous.”  
(sigh)  
“I’m going to need more fabric, fatty.”

That……is very irresponsible and inaccurate.  
Rarity would never do that. EVER. She is far more observativeon her clients and would make alterations if needed. I don’t see how this method can work in the slightest.

@Commander Hurricane  
Hah.

Someone’s been watching too many Special K commercials.

Yes, and I’m sure she charges the same price for larger clothes as she does for smaller ones. Because that makes sense.
 
Also, the Incredibles comes to mind for some reason.