Population studies are inherently difficult to interpret, and the most difficult are the studies that try to find associations between food intake and health outcomes. I’d like to point you to my post in which I addressed this issue in the context of the red-meat-is-bad fallacy (https://medium.com/right-to-rejuvenation/why-everything-you-read-about-red-meat-and-health-may-be-misleading-ecfe3cb04304).

The complexity of interactions between biomarkers and the variability of feeding patterns is simply too large to be accounted for. Population studies on the food-health interactions are inherently flawed. I introduced in that post the mathematical concept to prove that statement.

In another post (https://medium.com/right-to-rejuvenation/3-things-to-know-before-you-read-any-diet-article-2080093e361d) I describe a similar issue, that is, how to translate the study results into practical risk estimates for you, the lay reader.

With respect to the so-called blue zones: One reason for the extraordinary life-expectancy could also be a specific genetic variant that dominates within these populations AND for which their dietary patterns are an ideal match. But that is just a hypothesis. It is probably difficult to prove, or at least only with very considerable labor and expense.

I’d rather advocate for the opposite way of investigating the blue-zone dietary patterns: Find enough people having adopted the same or very similar dietary patterns in other parts of the world, use them as the control group and compare their life- and health expectancy with the blue-zone inhabitants.

Either one of those investigations can deliver definite evidence. But that, I’m afraid is along way off.