Current beauty aesthetic is just that: Current. In order to understand the willingness of so many women and young girls to engage in eating disordered behaviors to resemble a beauty ideal, we must first attempt to understand what that beauty ideal represents. Beauty ideals reflect the cultures that support them, hence the changing ideals through time and culture.
Most people understand the cultural influences that made the Rubenesque woman appealing in her time. Her big body represented wealth and childbearing capabilities. During a time and culture when food was limited, child bearing a more frequently life-threatening endeavor, where long cold winters put the fragile at risk, a big solid woman's body came to represent fortitude, stamina, health and survivability. However, when the Rubenesque artist put his brush to the canvas, he didn't set out to paint a wealthy child bearer. He set out to paint sexy, and big had become encoded as sexy.
Analysis of societal contributions to eating disorders often rest on the current waif aesthetic in modeling, essentially blaming the advertising industry for the pull towards Eating Disorders. Current beauty aesthetic only points to the question: what does extreme thinness in women capture, what values and qualities do we attribute to the thin woman?
Our clues lie in women's daily dialogue. We all know what a woman means when she walks into a room and says "I was so good today." It means she successfully dominated, deprived, repressed and controlled her hunger. If she says she was "bad today" it means she "gave in to" the pleasure, of say, a cookie. Women's responses to the thin woman's rejection of a piece of cake might shock us; "what willpower", "what self control", "she is so good." The thin woman rejecting cake is praised, not because we imagine she isn't hungry, or doesn't like cake, but rather because she has the willingness and capacity to dominate, suppress, and deny that hunger/want/desire.
Extreme thinness as a beauty aesthetic tells us what we want from women. Extreme thinness says something. It declares a willingness to dominate want. We needn't waste our breath telling young girls they don't need to be thin to be pretty. Instead we might better spend our time figuring out why needlessness as a character trait has become attractive in women. In this century, in this country, where women are stronger and more powerful that any other period or culture in documented history, the waif beauty ideal screams that a counter message is being whispered into the ears of our girls.