Many cultures have a recognizable cuisine, a specific set of cooking traditions using various spices or a combination of flavors unique to that culture, which evolves over time. Other differences include preferences (hot or cold, spicy, etc.) and practices, the study of which is known as gastronomy. Many cultures have diversified their foods by means of preparation, cooking methods, and manufacturing. This also includes a complex food trade which helps the cultures to economically survive by way of food, not just by consumption.
Natural foods and "all natural foods" are widely used terms in food labeling and marketing with a variety of definitions, most of which are vague. The term is often assumed to imply foods that are not processed and whose ingredients are all natural products (in the chemist's sense of that term), thus conveying an appeal to nature. But the lack of standards in most jurisdictions means that the term assures nothing. In some countries, the term "natural" is defined and enforced. In others, such as the United States, it is not enforced.
Although red wine contains the chemical resveratrol and there is tentative evidence it may improve heart health, the evidence is unclear for those at high risk as of 2013. Grape skins naturally produce resveratrol in response to fungal infection, including exposure to yeast during fermentation. White wine generally contains lower levels of the chemical as it has minimal contact with grape skins during this process.
The application of scientific knowledge to cooking and gastronomy has become known as molecular gastronomy. This is a subdiscipline of food science. Important contributions have been made by scientists, chefs and authors such as Herve This (chemist), Nicholas Kurti (physicist), Peter Barham (physicist), Harold McGee (author), Shirley Corriher (biochemist, author), Heston Blumenthal (chef), Ferran Adria (chef), Robert Wolke (chemist, author) and Pierre Gagnaire (chef).
Most food has its origin in plants. Some food is obtained directly from plants; but even animals that are used as food sources are raised by feeding them food derived from plants. Cereal grain is a staple food that provides more food energy worldwide than any other type of crop. Corn (maize), wheat, and rice – in all of their varieties – account for 87% of all grain production worldwide. Most of the grain that is produced worldwide is fed to livestock.