I see three possible avenues for this. 1. We get more sugar than them and sugar is worse than we realize. 2. They had less liberalism, and living with community and purpose was better enough to keep them going. 3. They died more and if anything was gonna make them sick they wouldn't have survived till old age so the survivorship bias is stronger.
So we just need to find a way to isolate those variables and do a regression for the data. Yeah?