From Science Daily: Agriculture, declining mobility drove humans’ shift to lighter bones.

Modern lifestyles have famously made humans heavier, but, in one particular way, noticeably lighter weight than our hunter-gatherer ancestors: in the bones. Now a new study of the bones of hundreds of humans who lived during the past 33,000 years in Europe finds the rise of agriculture and a corresponding fall in mobility drove the change, rather than urbanization, nutrition or other factors. [continue].

Excuse me while I go off to become ridiculously active.