Wow...I am thankful I don't act like that. The only time I talk about weight loss or surgery is when my one friend who knows about it asks me how I am doing post-op or comments about me losing weight. I don't bring it up because, I really don't care. Of course, it's only been a little over a month. I hope I do not become like your bypass friend. That's irritating.
My family, always ask and make comments about it when I talk on the phone with them. Not so much my mom, as she doesn't understand why I did it and I've given up trying to explain it to her. My dad and step mom seem to make a point of talking about their nieces, grand-children (not my kids...ick), or anyone else they know who is trying to lose weight the "traditional" way. Every phone call I hear about someone who has lost a few more pounds. It is irritating.
Anyway...sorry...those things have been bugging me and that just flew out of my fingertips...onto you. Again...Sorry!!!
You can pick your friends but you cannot pick your family...that's the old saying right? Well, I like to say, you can pick your family too. Irregardless of how we relate to them (family or friend, etc) it is our decision if we want to interact with them. If they are repeatedly acting in a way that is detrimental to your friendship, then say something about it, as, them what their problem is and deal with it. If they are unable or unwilling to do either, then do your best to be a friend when needed, but move on. We do not need people in our lives that bring us down through no fault of our own. It's one thing to be there for a friend who is in pain and needs some uplift. It's another thing completely to let someone's hang-ups cause us unnecessary anxiety.
I'm sorry your friends are being rude. If they are good friends, they will be able to move past whatever it is that is bothering them. If they cannot do that for the sake of their friendship with you, then you deserve better. I may be coming off a bit harsh, but that's how I see it. It is no different than coming out to your friends as a different religion, gay, or insert whatever thing that is not like them. They'll come around if they are your true friends. And that's how you know who you should spend your emotional effort on.
Okay...rambling-rant done. I wish you well.