This has interesting implications for Americans, most of whose ancestors immigrated from somewhere else; many of our ancestors also "hybridized" or crossed with immigrants from elsewhere. Trying to discover what dietary substances your particular genetic endowment is adapted to can be difficult and confusing. If both your parents were Italian and they were more or less pure Italian going way back, you might start out trying to eat wheat, olives, garlic, fava beans, grapes, figs, cow dairy. If pure German, try rye bread, cow dairy, apples, cabbage family vegetables. If Scottish, try oats, mutton, fish, sheep dairy and cabbage family vegetables. If Jewish, try goat dairy, wheat, olives and citrus. And certainly all the above ethnic derivations will thrive on many kinds of vegetables. Afro-Americans, especially dark-complexioned ones little mixed with Europeans, might do well to avoid wheat and instead, try sorghum, millet or tropical root crops like sweet potatoes, yams and taro. Making it even more difficult for an individual to discover their optimum diet is the existence of genetic-based allergies and worse, developed allergies. Later in this chapter I will explain how a body can develop an allergy to a food that is probably irreversible. A weakened organ can also prevent digestion of a food or food group. One more thing about adaptation to dietaries. Pre-industrial humans could only be extraordinarily healthy on the dietary they were adapted to if and only if that dietary also was extraordinarily high in nutrients. Few places on earth have naturally rich soil. Food grown on poor soil is poor in nutrition; that grown on rich soil is high in nutrition. People do not realize that the charts and tables in the backs of health books like Adelle Davis's Lets Cook It Right, are not really true. They are statistics. It is vital to keep in mind the old saying, "there are lies, there are damned lies, and then there are statistics. The best way to lie is with statistics."