No, it's a book, 'loosely based' on research dating to the 70's.
There's clear evidence that processed meats, too much meat etc (aka not enough greens?) is bad for you.
There's also very clear evidence that a vegan diet without supplements is bad for you, and who knows what supplements and micronutrients are really required over the long term, especially for child development?
From my memory is wasn't just animal products. The cultures that ate very low protein diets showed the same or better health stats as the ones that ate no animal products. My thought on this was that eating way less protein forces the body to conserve what it's got and turn of the cellular less at a lower frequency, thereby reducing the chances of mutation into cancer.
I think it's a good example of "correlation does not equal causation". The specific problem I remember reading about is that diet correlates with geography, and geography correlates with mortality through some parasites being more prevalent in certain areas and maybe other factors. So you can't draw a causative link between diet and mortality through a simple observational study.
https://en.wikipedia.org/wiki/The_China_Study