Rarely do the words (all, always, & never) apply as the answer to any question. Some people would not change a thing about themselves!
Having said that it's human nature for (most) people to want to fit in rather than stand out. Very tall people, short people, skinny, overweight, bowlegged, bald, cross-eyed, gap toothed, or whatever oftentimes want to change things about themselves. In fact many people who are considered "beautiful" dislike things about themselves.
It's probably not a stretch for someone to believe if a fat person had the "choice" to be fit or fat that they would choose to be fit. Nevertheless there are lots of people who have learned to love and accept themselves and are very comfortable in their own skin.
Just as thin people should not attempt to "shame" overweight people, overweight people should not attempt to "shame" thin or so called "beautiful people" with terms like saying she is not "A (real) woman", or she's a bimbo, or airhead. Each group attacks other groups.
It's also worth noting that "beauty is in the eye of the beholder". With a world population of over 7 billion people odds are in everyone's favor that there are people who are into whatever body type we are.