It's long been known that plant based diets are a healthy way of living. The George McGovern study of 1977 - Dietary Goals for Americans upset the meat, milk and eggs producers by promoting a plant based diet. Since then meat consumption has increased (more agriculture goes toward feeding the animals than feeding humans) and cancer, heart and other diseases have continued to rise.
Colin Campbell (The China Study) discovered that populations in rural Africa and rural China do not die of the top 10 leading killers in America, but if those people move to other countries they adopt to the lifestyle/environment and no longer have a low death rate from the top ten killers, showing it is environment and not genetic.
Plant Pure Nation has an interesting documentary (available on Netflix). Plant based meals were provided for a selection of the population of Mebane, NC for ten days with amazing results of lowered cholesterol and general health.
As a nation we take more medication (which has numerous side effects) than any other country and yet the diseases are not reduced. One doctor interviewed said 80-90% of patients would have improvement of health with whole foods as opposed to drugs, but unfortunately doctors rarely learn about nutrition as part of their education and most do not suggest change in diet as opposed to drugs.