constant struggle

Why is it that women spend so much of their time on 'losing weight'.

All of my life, every woman I know has wanted to .. 'lose weight'. 

It's not specific, like.. I want to lose 3 lbs, (or sometimes it is) it is always vague.. just want to lose weight. 

Generations of 'wanting to lose weight'... Years of talking about it, wasting energy on it, headaches over what they just ate.