If you walk around an art museum, you're likely to see lots of curvy, plump female nudes among the models in the artwork. For many centuries, being thin meant that you were poor -- you didn't have enough food to eat and you spent your days burning off calories in the fields. Being a full-figured man or woman, on the other hand, was a symbol of wealth and beauty.
Beginning in the late 1800s, the word "diet" started to creep in to our vernacular, and at first, dieting advice was only aimed at men because women were expected to be voluptuous [source: Vester]. As the decades went on, a little extra flab became something to be ashamed of, and slender became the figure to strive for. While plenty of critics will point out that pictures of models and celebrities are airbrushed and Barbie has impossible-to-achieve proportions, both men and women seek to be thin, sometimes through extreme methods such as disordered eating, unhealthy amounts of exercise and plastic surgery.