South American group has the healthiest arteries ever seen. I think the writers of this article are making the same mistake that the Atkins diet crowd makes. It is not the diet that matters. It is this “While people living in cities are sedentary for more than half their waking hours, the Tsimane are inactive for only 10 per cent of the day.” The same things has already been noted for the Amish. Amish who are active all day long (farmers) and Amish who are not active all day long (shop keepers) have the same diets but wildly different health outcomes.