Chinese cuisine includes styles originating from the diverse regions of China, plus styles of Chinese people in other parts of the world. The history of Chinese cuisine in China stretches back for thousands of years and has changed from period to period and in each region according to climate, imperial fashions, and local preferences. Over time, techniques and ingredients from the cuisines of other cultures were integrated into the cuisine of the Chinese peoples due both to imperial expansion and from the trade with nearby regions in pre-modern times as well as from Europe and the New World in the modern period.
Styles and tastes also varied by class, region, and ethnic background. This led to an unparalleled range of ingredients, techniques, dishes and eating styles in what could be called Chinese food, leading Chinese to pride themselves on eating a wide variety of foods while remaining true to the spirit and traditions of Chinese food culture.
Cooking is the art or practice of preparing food with the use of heat or cold for consumption. Cooking techniques and ingredients vary widely across the world, reflecting unique environmental, economic, and cultural traditions. Cooks themselves also vary widely in skill and training. Cooking can also occur through chemical reactions without the presence of heat, most notably as in Ceviche, a traditional South American dish where fish is cooked with the acids in lemon or lime juice. Sushi also utilizes a similar chemical reaction between fish and the acidic content of rice glazed with vinegar.
Preparing food with heat or fire is an activity unique to humans, and some scientists believe the advent of cooking played an important role in human evolution. Most anthropologists believe that cooking fires first developed around 250,000 years ago. The development of agriculture, commerce and transportation between civilizations in different regions offered cooks many new ingredients. New inventions and technologies, such as pottery for holding and boiling water, expanded cooking techniques. Some modern cooks apply advanced scientific techniques to food preparation.