I'm not sure I grasp your point, but I'd like to understand better.
Could I ask what phenomenon is "dangerous"?
(I hope I don't sound snide or argumentative -- I honestly want to understand your point. Thanks.)
Girls (up through adults) are increasingly obsessed with their looks and achieving the "perfect" body in particular. I can't cite any particular study that would define this trend. I'm just extrapolating from my own observations. But a good indicator of the extent of this problem might be a rise in the cases of anorexia among teenage girls.
Why is this a problem? There are many reasons, both positive and negative. Positively, poor body image can result in pathological behavior among girls and young women and, along with the impossible expectations of young men, also makes it more difficult to achieve healthy long term relationships, i.e. healthy marriages. In our culture, women are increasingly measured by the sum of their body parts, not the content of their character.
Secondly, this "cult of the body" is an enormous waste of time and talent. Young women simply waste an enormous amount of energy and resources in a hopeless pursuit of bodily perfection. This vice used to be known as vanity. Which wife is of more value, a plain, virtuous wife or vain, pretty wife? Which will contribute more to society? The classic example is the amount of ink spilled over the deaths of Mother Theresa versus Lady Diana in the media.