It might be that a 'poorer' diet can be better. Reason being that they use more raw foods rich in fiber rather than processed flour, sugar, oil, etc. See resea

It might be that a 'poorer' diet can be better. Reason being that they use more raw foods rich in fiber rather than processed flour, sugar, oil, etc. See research on the Okinawan diet. People there had the some of the longest lifespans ever recorded and they ate mostly potatoes (albeit a very nutritious variety of purple sweet potato). Today Okinawa is rich, there are 3 KFCs on the island, and their lifespan has declined.