Thanks - followed back.
It helps to understand that 'Doctor' actually means 'teacher' and there are many with the title of Doctor who do understand nutrition very well, but since they are in the minority they are not usually 'GP's - but are more elevated in society (finally, now) and can be found on the web. Dr. Greger at nutritionfacts.org and the Chiropracter John Bergman are two of note.