This reminds me of the old saying:
Question: "What do you call a med school student who graduates at the very bottom of their class?"
Answer: "Doctor."
All kidding aside, there are good doctors and bad doctors. If your doctor is fat, I'd say, take that into consideration. I don't seek stock market advice from homeless people, and I don't seek expert nutrition advice from the obese. Now, don't everyone take that personally, because I don't mean all the wonderful information and support we all share with each other here. What's nice about 3FC is you have thousands of women with experience in the trials and errors of weight loss, as well as some great success stories. 99% of the people here simply share their story and advice based on experience and don't pretend to be experts. The other 1%... well, I ignore them.
I would ask to be referred to a dietitian or nutritionist who's probably a little more up to date on their specific field than a general practitioner would be.