I have been reading "how not to die" by gene stone and Michael Gregor. During the book, people were classified as either meat eaters (eat meat more than 4 times a week), or plant based eaters. meat eaters had a much higher risk of obtaining diseases (heart attack, stroke, and so on) compared to vegetarians.
I believe this may be similar to "brushing your teeth makes you live longer". People who brush their teeth generally take better care of themselves anyway. The cause and effect of not eating meat is what I'm interested in.
Of meat eaters, there would be healthy eaters and unhealthy eaters (fresh chicken salads vs KFC). With vegetarians, there are a lot less people eating unhealthy foods since they are more health conscious (once again, these are generalisations, but the scientific data is based on percentages as well).
I am wondering if anyone knows of any books or scientific reports where they keep clean meat eating as a control against vegetarianism. I believe this would be more accurate in determining the health benefits of vegetarianism.