I hate the phrase. It pisses me off. Its rude and dismissive.
I am not going to pretend I am oppressed because I am slim (and have been very thin), I am sure someone who is obese has to put up with a lot more crap than me.
But people do seem to think they have free rein to talk about my weight and comment about my diet. WTF is that about?
I have 7 SIL. Nearly all of them are large women. They made a lot of comments for years and I ignored them. (I have told this story before I think). My DD became ill and lost her appeitite. I tried to get her to eat and was frantic. She lost quite a bit of weight. It was a terrible time. She was eventually dx with cancer.
I said to my OH that I bet at least one of his sister's would say it was my fault she was so thin and that I was obsessed with my weight (not, never have been, never owned a set of scales).
OF course not, he said.
Guess what? Yes. "we thought you were making her anorexic because you wanted her to be thin like you"
Because all women who were not 'real' like them were child starving narcissists 
That did hurt, a lot.
When I expressed my concerns to a dr about DD becoming over concerned with her weight (its a big issue when you are on treatment, they go on about it all the time and weigh you). She automatically assumed that i was worried about her putting on weight and told me 'dont worry any weight she puts on with the steriods will go away eventurally' with a look on her face that told me what she thought of me!
NO! I was so worried about the pressure being put on her at such a vunerable age. Like I cared if she got fat! I wanted her to live.
She did become anorexic.
How fucking ironic is that.