It sounds like the OPs weight has been discussed in the past w/ her Doctor & nurses & they know where she stands. When the OP is ready to discuss her weight again with them, it sounds like she will do so & take control in her own timing. It sounds like she has put much thought into this subject. If I understand correctly, the nurse prompted her & she wasn't ready to go there, so she ended the subject. When the time is right for the OP, it sounds like she is aware enough to move forward on the subject.
The POINT behind my post was that the 'accepted' phrase just rolled off my tongue without even thinking about it. My weight is not now, nor ever will be, a topic for discussion on this list or anywhere else.
This is just my opinion, but if you have never addressed the subject of your weight with this particular nurse, how was she to know it was an out-of-bounds topic?
I feel you were quite snippy to her.
"Why would I want to do that?" would be an appropriate response to a nosy family member, friend, neighbour, or perfect stranger. However, since there are really legitimate reasons for you to "want to do that" in this case, it's not an appropriate thing to say to a medical professional who is trying to help you. You're lucky she dropped it, but she may just as likely have gone into the list of reasons why you would "want to do that", and she would have been perfectly polite in doing so, since you all but invited her to give you a list of reasons.
A better response to a medical professional (who is trying to help you look out for your health and wellbeing) would be "I don't wish to discuss my weight right now" or "No, it is not a goal I plan on setting."
As hard as I try, I do not see the nurse as being rude, presumptuous, or at all in the wrong with her comment. It reads to me like she was attempting to bring up a very sensitive subject as delicately as she could. I'm sorry, but I still feel you were rude to her.