
My attempts to lose weight were immediately apparent to her because we almost always started the day with pastries from the local bakery and ordered in for lunch. And from Day One she has had advice. "I read that you should..." "I heard that you should..." "Oprah says...." "You shouldn't eat that....." "My friend lost 200 pounds by eating nothing but chocolate cake for six months."
And it's the same thing with exercise. Not only does she have advice but she compares me to other people. When I come in to the office in the morning, she asks how long my run was. No matter what I tell her, she knows someone who ran further that day or exercised more.
Also, she is NOT skinny. I would guess that she is 50 or more pounds overweight. And very unhealthy. She's totally in denial about it. She actually says things like, "I'm so glad I don't have to diet" and "I'm fortunate that I don't have to exercise."
I have tried to calmly and rationally explain to her that I'm doing what works for me. I have gritted my teeth and kept my mouth shut. But yesterday she just totally annoyed me.
She has been going through a bit of a personal crisis for about a month, and she claims that she hasn't been able to eat anything at all through the whole ordeal. Yesterday she announced that had lost 25 pounds. Bull****! Isn't it pretty much physically impossible to lost 25 pounds in three weeks? And if you didn't eat anything at all for a month, wouldn't you be dead?
I have worked so hard to lose just 20 pounds in 5 months. I'm trying to do this in a way that is sane and healthy. And I feel like every day at the office I have to defend that. And now she is lying and trying to prove she's better than me or something.
I honestly do not want to go to the office today. I think I'll go postal on her if she says one more thing.


on the spot about her supposed weight loss. I don't know if I could be so catty, but it would be really enjoyable to say something like, "I bet you're going to have to go shopping this weekend for new clothes since you've lost so much weight!" 

Good luck, I know how difficult it is, because after all, you still have to work with them.