Thin lady and fat lady switch

[Mel]

I’m looking for a book or possibly short story, possibly written in the late 80’s or early 90’s. It was about a fat lady who traded places with a skinny lady. I remember the skinny lady in the bigger body was at first nervous to eat, but then felt freer. She began to eat, but more sensibly, and lost some weight. The big lady in the small body learned to eat better. She gained some. I think the point was they learned from each other... they decided to stay in the new bodies. I am trying to find this book/story. Anybody know it??

[Kris]

Mel, what's the genre (which we need to add to the topic header/title) - e.g., adult realistic fiction, chick lit, humor, romance?

[Mel]

I'm sorry; just saw this. I think it was children's literature, but I'm not sure!