two years out (from surgery). I told my housemate, my doctor (after the fact) and one friend who asked. I have told health care professionals with a "need to know".
I'm glad I handled it this way. It would have been a curiosity for some, an excuse to judge for others, gossip for others, a diversion from true relating for others. I'm glad I did not divert everyone around me by making it a topic. Since I lost slowly, no one really made a fuss. And, finally, when people DID ask how I lost the weight, I said, Well. among other things, more exercise than I ever thought I do and less food than I ever thought I'd be able to put up with"..... That is true AND it ends the "discussion". No one is really that interested.
Good luck!!