It works both ways though. I'm 5'5 and a size 8 and I get so sick of being referred to as "skinny" by women who are at all bigger than me.
Skinny is also an unflattering term that suggests ill-health, and in my experience is often used with an edge in the voice.
Honestly the things people seem to think it's ok to say to me! A friend was passing round some biscuits once and another friend said, "No it's alright, Fuckit's already eaten this week!" I would never dream of making disparaging comments about her weight. If I told her she needed to lose a few pounds (which quite frankly she does), that would rightly be deemed offensive.
I am not "skinny". I am slim, tallish (especially in heels) and despite having had three children and things not being quite what they used to be, I still have a streamlined hourglass shape and I still really like my figure. I consider myself to be really lucky.
All those barbed "skinny" comments and references to "real women" (as opposed to what exactly?) just come across as really bitter and jealous.
I couldn't give a flying eff what Kirstie Allsop looks like. I dislike her on the basis of her nasty politics and blatant materialism.