I told her she doesn't need surgery, and that losing weight is very simple
When you get fatter you produce new fat cells. When you get thinner your fat cells shrink. Then you have those fat cells demanding to be plumped back up.
Losing weight is about fighting cravings. You can win the fight by having lots of will power or you can win the fight by reducing the cravings. Fat removal surgery will help reduce the cravings, making the fight more winnable.