I agree, EC. There's a certain social code among women at least when it comes to weight.
There is a tangible sense that in order to be 'admired', you have to be either slim enough OR have a buoyant personality to compensate for the fact that you're fat/not extremely slim.
Of course if you have the weight and the personality you're going to be someone other women really want to be like. And wanting to be like someone is a double edged sword. It involves adoration and resentment. It's actually painful to want to be like someone if you feel you are not able to be like them.
A lot of people experience this pain and rationalise it on some level as being because the person they want to be like has caused it. This isn't true.
It leads to an awful lot of bad feeling between women because of their different weights. And that thing of 'haven't you done well' or 'battling to lose weight' as though it were so, SO important to be slim that almost any sacrifice is worth it.
I admit that when I stopped eating almost entirely in my twenties, and started to lose weight dramatically, it was after a few years of struggling with my body and hating the parts that had grown a bit fat - I'd been skinny since primary school and always was given admiration for the shape of my body.
And as this happened, as I shrank and became able to wear clothes that I'd never nave dreamed I'd get into previously, I was thrilled. It was so exciting to have this sense of power, of being looked at differently, as though I was somehow special because I could wear what I wanted to.
It did not last very long. Soon I found I could not stop the weight loss and it began to frighten me, and the clothes I'd felt so excited about for a brief few weeks now hung off me, and I looked very unattractive. I did not feel attractive again for about 4 years, when I began to eat again. then I went through the same process backwards and luckily, thankfully, stopped somewhere I felt alright.
So I know how powerful it is to lose weight and how magical it can feel. And how having people know how you did it, if it involved something very much NON magical, would take away from that - perhaps necessary? - sense of personal power. And why people finding out this secret would resent it, because they too know how magical it would feel to you, and that's why they might see it as cheating.
But it isn't. There is the reality and there is the fantasy and it's important to keep these discrete. No one has the right to know. The feelings around your own weight loss (or in my case gain) are yours and yours alone and an intrinsic part of the process. No one else should care.
I hope you can sort it out with your friend, it sounds like she made a judgment that everyone would guess anyway, and yes thatwas wrong of her but she sounds sorry.
Let us know how you go with this, if you can OP. And good luck.