In ancient Greece, and later Rome, who adopted Greek culture, the benchmark was considered athletic body for men, chiseled and muscular, without a drop of excess fat. By the way, the male canon does not change much over the millennia, while the women had a bit more complicated. Ancient Greek ideal - a woman of about thirty with chubby cheeks and double chin a little, little juicy breasts, slightly protruding belly, which men call appetizing, and moderately full legs. To be sure, just look at the statues in museums of ancient history. Thus, from the point of view of the Greek ideal was the usual plump girl.
This standard has lasted a very long time, by today's standards. But with the advent of Christianity in Europe naked female, and the male body was considered immoral, and in the Middle Ages has been, to put it mildly, is not held in high esteem, so the focus was exclusively on the face. In the Middle Ages was considered a beautiful girl from 20 to 25 years, with a refined aristocratic features: neat nose, small tightly compressed lips, high forehead and almond-shaped eyes. Ie very thin woman, with slightly released any organic shapes, "in order not to excite lust."
Renaissance - a turning point of history. She touched the whole of European culture: poetry, music, sculpture, painting, etc. It is not surprising that along with everything else back to ancient standards and the concept of beauty. If you look at the tapestries and paintings of the Renaissance, you can see all the same bulk and roundness, as in ancient times. Sculptors and painters have immortalized in their works of Venus, Aphrodite, Athena, and their nudes, were undoubtedly the beautiful lush contemporaries.
In XX century ideals have changed with great speed, sometimes women do not have time to lose weight or gain: in fashion frankly skinny vamp, the warlike Amazon, the ancient Danae, and then again a strict aristocrat. The impression is that over the past 100 years, fashion has tried to taste all ages of the world.