women beauty

I appreciate beauty and wonder what are its characteristics nowadays. I noticed that "beautiful" women, or at least the ones that are considered beautiful (models), are the slimmest ones, with filiform bodies.

In Germany, polemic debates were raised when, in a TV competition of top models, one of the candidates got excluded because she was not anorexic enough (52 kg - 1,76 mètre). But this country has 100 000 cases of endocrinian insufficiency (people not eating enough) every year, and this program on the first channel of the country doesn't help much.

Disconnected from the modern civilized culture, my anachronical mind has been influenced by the middle age. I know that, by those times, body corpulence, which might also be called "fat", was considered as one of the basics of beauty. No wonder if many artists made portraits of not so squelletic faces and bodies (please take a look to the splendid "Mona Lisa").
Why is it that today's women try to be skinnier and skinnier? As far as I am concerned, I just blame it on medias, that influences both sexes: altering man's taste and woman's behaviour.