Sorry, but what kind of people are you to telling this? :S...I don't think so, thing is that some girls can't accept the truth, specially the ones who live in Spain. So they have a high ego. In fact if you go to the north of Europe like Finland or places like that they take it very calmly (?).
And obviously i know girls get pretty annoyed if you call them fat. I remember there was one in my class who was very good looking and thin, who was eating some kind of pastries similar to donuts. And i told her "deja de comer gorda" and she stopped eating. The day after a friend of her, who is a good friend of mine told me that she feels "acomplejada". And with this i want to say, people take things to serious when they shouldnt.
PD: Perdón por el toxo. jajaja