The next logical pair of questions are: how healthy could good nutrition make people be, and, how much deviation from ideal nutrition could we allow ourselves before serious disease appears? Luckily, earlier in this century we could observe living answers to those questions (before the evidence disappeared). The answers are: we could be amazingly healthy, and, if we wish to enjoy excellent health we can afford to cut ourselves surprisingly little slack. Prior to the Second World War there were several dozen sizable groups of extraordinarily healthy humans remaining on Earth. Today, their descendants are still in the same remote places, are speaking the same languages and possess more or less the same cultures. Only today they're watching satellite TV. wearing jeans, drinking colas--and their superior health has evaporated. During the early part of this century, at the same era vitamins and other basic aspects of nutrition were being discovered, a few farsighted medical explorers sought out these hard-to-reach places with their legendarily healthy peoples to see what caused the legendary well-being they'd heard of. Enough evidence was collected and analyzed to derive some very valid principles. First lets dismiss some apparently logical but incorrect explanations for the unusually good health of these isolated peoples. It wasn't racial, genetic superiority. There were extraordinarily healthy blacks, browns, Orientals, Amerinds, Caucasians. It wasn't living at high altitude; some lived at sea level. It wasn't temperate climates, some lived in the tropics, some in the tropics at sea level, a type of location generally thought to be quite unhealthful. It wasn't a small collection of genetically superior individuals, because when these peoples left their isolated locale and moved to the city, they rapidly began to lose their health. And it wasn't genetics because when a young couple from the isolated healthy village moved to town, their children born in town were as unhealthy as all the other kids.