Many years ago I did a bit of research with older teens (17-19) on female attractiveness using 6 different pictures of women.
Interestingly, some of the comments I received from young women were 'I wouldn't really want a very obese friend'. Young men on the whole chose a hot- looking, blonde, bubbly type as someone to be their girlfriend, but a more 'mumsy' looking type as potential wife material.
As someone who has been obese, I did have the misfortune to have someone I thought of as a good friend who I overheard one day (I came to the top of a staircase unexpectedly - she was giving forth below

) telling some male friends of mine that she liked hanging out with me because it made her look slim. She got dumped soon after by me and one of the guy friends asked me why on earth I was friends with her (though he didn't know I had overheard her and he didn't tell me what she had said).
Personally, my life was blighted from teenagehood by thinking of myself as unattractive.
I do just want to ask if you know of many very obese women in the UK or US who are in high positions in companies or government? I ask because my experience of the UK is that very obese women are very rarely found high up the trees because they won't push themselves forward because they know for sure people are looking at them with judgement thinking "look at the state of that, she obviously can't control herself in the face of a batch of cream buns, how dare she presume to have any opinions whatsoever".
Here in Egypt, while I don't condone extreme obesity as an aspiration, you find MANY women in high positions who are very obese. It does not define them in the way it does in the UK. I was very surprised when I ran a summer school for kids a couple of years back and all these ginormous women came along with their kids and they were all 'doctorah' this and 'professorah' that and 'head of the other government department'. In the UK none of them would have aspired to anything higher than Walmart Till Operator on the basis of their size.