Looking at individual diseases is informative, but it can cause us to become myopic, making broad health-related decisions based on narrow information. It can cause us to miss the forest for the trees. In this case, the "trees" are individual diseases and the "forest" is total mortality: the overall risk of dying from any cause. Does eating meat increase total mortality, shortening our lifespans?
Traditionally-living cultures such as hunter-gatherers and non-industrial agriculturalists are not the best way to answer this question, because their mean lifespans tend to be short regardless of diet. This is due to ~30 percent infant mortality, which drags down the average, as well as a high risk of death in adulthood from infectious disease, accidents, and homicide/warfare. It can also be difficult to accurately measure the age of such people, although there are reasonably good methods available.
However, there are semi-industrialized cultures that can help us answer this question, because they feature a somewhat traditional diet and lifestyle, combined with modern medicine and the rule of law. The so-called Blue Zones, areas of exceptional health and longevity, fall into this category. These include Sardinia, Italy; Okinawa, Japan; Loma Linda, California; Nicoya Peninsula, Costa Rica; and Icaria, Greece.
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