It would be so much better for her health if she lost weight, and just wore Kevlar armor all the time.
This may be the oddest reason I've heard for people not wanting to lose weight, but it's not the only one. I've heard about women who become large because they are intimidated by men's attention and prefer to be left alone, and very petite folks (of both sexes) who gain weight because they want to take up more space and be more noticeable/formidable, instead of being brushed aside.
If you understood everything I say, you'd be me ~ Miles Davis
'There is only one success – to be able to spend your life in your own way.’ Christopher Morley.
It involved a mannequin hand, and an electric shaver taped to a golf club! - "The Other Guys"