It could be the pressure of 'staying pretty'
making them hate themselves for eating to the point of detriment.
I understood that ozempic, the weight loss drug, is also widely used, which could be additional peer pressure.
These people are constantly scrutinised under a microscope, it's a lot to handle.
Obviously all speculations, there could be other reasons.

+ the initial complex animation stutters on Firefox mobile. Other examples run smoothly.
Very interesting anyway, I'll look into it properly later. I've been trying to get some vector animations made and the free(ish) editors I could find were painful to use, so an alternative is most welcome.