I'm going to echo what LoriAS said about the negative comments - it sounds like some people are really offended that you are even considering talking to the doctor when you are here to get advice from people about the right thing to do. I posted a thread that proved to be a bit controversial and got a lot of negative responses for merely asking for help. Luckily, there was a lot of good advice in other members' posts.
The best advice I got from someone here (whose name escapes me) was to lead by example. If she sees you losing, making healthier food choices, exercising, etc, she may be compelled to join in if she's ready to lose. If she does, that's great, and maybe it can be something you two do together. If she doesn't, just keep doing what you're doing and she might come around. A simple gesture like inviting her to a work out might go a long way, but I would try and make it more about an activity to do as friends than to do to lose weight. If a friend said to me "My runs are lonely, want to come next time?" I'd be way more like to go than if she asked "We really need to work out."

