doctors learn/study very little actual nutrition while doing their degrees and training.
unfortunately.... medicine is treatment through drugs and surgery, not prevention through healthy lifestyle.
Recent research may allude more to meat eaters being more aggressive.
This is my two cents. of course more research is needed, but what I gather, it is in favor of fruit, raw foods, and vegetarian diets.
Ppl tend to forget that there was a time before the fire was discovered.
And by the time it was discovered I'm sure that the first idea ppl had back then was not to put dead meat over the fire to see what it tastes like.
According to the archaeological record, our lineage has been hunting for about 2 million years ( and we weren't hunting plants:) We harnessed fire about a million years ago so we were eating raw meat for a long time. Vegans seem to have a hard time accepting the evidence that strongly indicates that early man ate meat along with fruits and vegetables. How much meat we ate was dependent on how much vegetation was available. According to the climate record, the tropics of Africa underwent periods of drought (desiccation). We ate meat for survival. What is not clear is whether or not eating meat had anything to do with brain size or intelligence. And a big brain doesn't always equate to more intelligence. There are plenty of small brain carnivores.
As far as meat being "necessary for protein for cancer", that's an oldie but a goodie :-)