The work of Weston Price--who traveled the world in the 1920s and 1930s--comes to mind. He discovered that eating a traditional diet (never vegan...high fat & protein whenever available) produced wonderful health. A dentist, he took copious photos of teeth from natives. The diets varied widely, from grass-fed cheese and whole grain bread in Switzerland, where he found an isolated valley untouched by modern ways, to insects and game among the Aborigines, to almost entirely meat among native people's in Canada. I am glad you corrected the misconception that the Mediterranean diet is mainly found in Greece.