If you have to ask, the answer is probably no.
If you were in a place with him that you had a deep connection/relationship, you wouldn't be asking us you would just tell him.
I wasn't dating anyone at the time I had surgery. The people have I dated post-op, I have been honest with about losing weight and trying to get in better health, but I haven't mentioned surgery. None have ask and most aren't curious that I have lost/am losing weight. They just like that I'm pretty and look amazing in a dress.