For me I had no problem telling my Parents and will probably tell the rest of my family after the fact.
But I'm completely and utterly mortified of people at my work place finding out. It's embarrassing to me.
And I think the reason is because it's admitting out loud that I'm FAT.
Before I would just pretend people ignored that about me, but actually saying to them "Hey I'm fat and can't lose weight on my own" that just makes me want to crawl under a desk and never come out.
Ironically I actually ended up telling my boss because 1) it made it easier to request that much time off and 2) I figured he would realize it eventually anyways.
It was difficult telling him but i did it via chat and that took some of the sting off.
I still don't want my other coworkers to know, but i figure after its done i'll probably end up casually mentioning it to them.
I'll still be embarrassed but i've told myself to just suck it up and move on.