The history of Chinese cuisine is marked by both variety and change. The archaeologist and scholar Kwang-chih Chang says "Chinese people are especially preoccupied with food" and "food is at the center of, or at least it accompanies or symbolizes, many social interactions". Over the course of history, he says, "continuity vastly outweighs change." He explains basic organizing principles which go back to earliest times and give a continuity to the food tradition, principally that a normal meal is made up of grains and other starches () and vegetable () or meat dishes . Overview The Sinologist Endymion Wilkinson has highlighted a succession of incremental and successive changes that fundamentally altered the "richness of ever-changing Chinese cuisine": The expansion of Han culture from the upland stretches of the Yellow River across a huge and expanding geographical area with climate zones ranging from the tropical to the subarctic, each providing new ingredients and indigenous cooking traditions; An elaborate but continually developing traditional medicine which saw food as the basis of good health ("Food was medicine and medicine, food"); Constantly shifting demands from elites – beginning with the imperial courts and provincial governors but eventually expanding to include rich landowners, "scholar-gourmands", and itinerant merchants – for specialised cuisines, however far away from home; and Continuous absorption of diverse foreign influences, including the ingredients, cooking methods, and recipes from invading steppe nomads, European missionaries, and Japanese traders. The philosopher and writer Lin Yutang was more relaxed: How a Chinese life glows over a good feast! How apt is he to cry out that life is beautiful when his stomach and his intestines are well filled! From this well-filled stomach suffuses and radiates a happiness that is spiritual. The Chinese relies upon instinct and his instinct tells him that when the stomach is right, everything is right. That is why I claim for the Chinese a life closer to instinct and a philosophy that makes a more open acknowledgment of it possible. Chinese cuisine as we now know it evolved gradually over the centuries as new food sources and techniques were introduced, discovered, or invented. Although many of the characteristics we think of as the most important appeared very early, others did not appear or did not become important until relatively late. The first chopsticks, for instance, were probably used for cooking, stirring the fire, and serving bits of food and were not initially