obviously from a lot of people saying it's from themselves the root of this pressure to look good is ingrained from our patriarchal society eenforced by friends family, coworkers bosses teachers -people of authority, the media and other things
They say they do it for themselves - they have to look good physically before they mentally feel good about themselves, that isnt free thinking.
Anyway i dont know why this topic is exclusively aimed at girls when there is also growing pressure especially to younger boys & men to also look good, I mean even I as a boy am going to start going to a gym and going on bulking diets to build muscle because i dont feel comfortablle in my body as ive placed a muscled physique as my ideal or even as the norm to me, was that my choice? No there have been many outside influences but oh well