Does everyone tell their coworkers that you had surgery?

Wow! I can't believe your boss told your private medical health business to other people. She had no business or right to do that! That is not professional at all and you're right. Not cool at all! I would never tell her anything private again. I don't know if you work for a small company or large, but I would think that would be against the law or at least a company rule.

NOPE!  I told my coworkers and bosses that I was taking off for 4 weeks because I was having surgery, but did not tell them what kind of surgery.  I'm over 8 months out and I still have not told them because it's personal medical information, and my office is really good about respecting personal boundaries.

I have told two people in my life, nobody else.  It isn't anyone elses business but your own.

If you don't want to tell, don't. It is OK to not open your life to coworkers. Some people never tell others and just leave people with their assumptions. Do what works for you!

I did tell people. I was fine with being this "open book" because I knew I could verbally eviscerate anyone who said some thing negative. I'm sweet as can be... until you cross me. Everyone at work knows that about me. So if anyone had any negative comments, I've never heard them.

Truly is a personal decision ... I told my office co-workers and they were nothing more then supportive and encouraging.  I think it really depends on the relationships you have with your co-workers ... we're a small group and share a lot! You should not be embarrassed for taking control of your life and health ... be proud of yourself! 

I didn't plan to tell and didn't until I reached goal at which point I decided I was comfortable sharing the information.

No, I did not tell my co-workers or anyone but 2 people other than my husband. It's nobody's business. They've all seen me yo-yo weight before so they are non the wiser.

I just told people I was out for surgery.  Did not tell them what kind.  I assume I'll get questions later once I've lost a significant amount of weight and I'll probably be fine with outing myself then.  

In the meantime I don't want the pressure of people watching me to see if I lose the weight and keep it off.

I really fought with this for a while, but I don't plan on giving specific details about what op I'm having. I've been losing weight for a while now but still pre-op, and a couple of colleagues know I've been working on my weight for a while now, so I don't think it'll be an overly obvious change afterwards.