Hunter-gatherer past shows our fragile bones result from inactivity since invention of farming

http://www.sciencedaily.com/releases/2014/12/141222165033.htm

Date: December 22, 2014
Source: University of Cambridge

Summary:
Latest analysis of prehistoric bones show there is no anatomical reason why a person born today could not develop the skeletal strength of a prehistoric forager or a modern orangutan. Findings support the idea that activity throughout life is the key to building bone strength and preventing osteoporosis risk in later years, say researchers.