Why eat raw?

Wondered why you wanted to go raw? (Hope this forum isn't like a certain other, where to question is a sin. :D :D)
Just curious since my home is near the Med - though I'm having to do a job in the "frozen" north right now (yuk) - and people down there have the western world's lowest incidence of heart disease and obesity related diseases. A lot of people put that down to the diet, so I wondered where the "raw is good" idea comes from?