I'm inclined to say "hey... why don't you just tell the truth, you big fat liar!" Which would no longer be totally true
But she doesn't have to share her secrets. She's getting/is healthy and going to the gym and eating right so that isn't a lie. Good for her for the lifestyle changes.
An aside - does anyone know what % of bypass patients keep their weight off? I know 2 people who have had it done (approx. 4 years ago) and they are both gaining significant amounts of weight back. I assume the stomach stretches out, allowing more food to be consumed, allowing someone who hasn't really committed to change to put weight back on?