Gotta remember that back when the things that make up the Bible were written, fat people were pretty synonymous with wealth. Hard to get fat when you barely have any food.
Sure, but even then, there's often a distinction between being a little chubby (good) and being obese (bad). It's that cultural carry over from when only the wealthy could afford it.
a little chubby is also good in my first world book, I think it's some kind of instinct, since a chubby woman would have no problem nourishing a fetus, even during winter. She also wouldn't have trouble with breast feeding