is any substance, usually comprised primarily carbohydrates, fats, water
and/or proteins, that can be eaten or drunk by animals (including
humans) for nutrition and/or pleasure.
Most traditions have a recognizable
cuisine: a specific set of cooking traditions, preferences, and
practices, the study of which is known as gastronomy. The study of food
is called food science. In English, the substance food is often
used metaphorically or figuratively, as in food for thought.
Almost all foods are of plant or animal
origin, although there are exceptions. Almost every form of life has
been used as food, either for nutritive or ritual purposes, by one or
more human societies at some time in the past.
Foods from plants
Many plants or plant parts are eaten as
food. There are around two thousand plant species which are cultivated
for food, and many have several distinct cultivars. Plant-based foods
can be classified as follows: Seeds, the ripened ovules of some plants,
carry a plant embryo inside them along with the nutrients necessary for
the plant's initial growth. Because of this, seeds are often packed with
energy, and are good sources of food for animals, including humans.
In fact, the majority of all foods
consumed by human beings are seeds. These include cereals (such as
maize, wheat, and rice), legumes (such as beans, peas, and lentils), and
nuts. Oilseeds are often pressed to produce rich oils, including
sunflower, rape (including canola oil), and sesame.
Fruits are the ripened extensions of
plants, including the seeds within. Fruits are made attractive to
animals so that animals will eat the fruits and excrete the seeds over
long distances. Fruits, therefore, make up a significant part of the
diets of most cultures. Some fruits, such as pumpkin and eggplant, are
eaten as vegetables.
Vegetables are other plant matter which
is eaten as food. These include root vegetables (such as potatoes and
carrots), leaf vegetables (such as spinach and lettuce), stem vegetables
(such as bamboo shoots and asparagus), and inflorescence vegetables
(such as globe artichokes and broccoli). Many herbs and spices are
Foods from animals
Meat is eaten. Often other animal
products are eaten as well. Mammals produce milk, which in many cultures
is drunk or processed into dairy products such as cheese or butter.
Birds and other animals lay eggs, which are often eaten. Many cultures
eat honey, produced by bees, and some cultures eat animal blood.
Some foods do not come from animal or
plant sources. These include various edible fungi, including mushrooms.
Fungi and ambient bacteria are used in the preparation of fermented and
pickled foods such as leavened bread, wine, beer, cheese, pickles, and
yogurt. Many cultures eat seaweed, which is a protist, or blue-green
algae (cyanobacteria) such as Spirulina. Additionally, salt is often
eaten as a flavoring or preservative, and baking soda is used in food
preparation. Both of these are inorganic substances, as is water, an
important part of human diet.
English-speaking countries usually
define four categories of substances as food:
- any substance, intended to be, or
reasonably expected to be, ingested by humans;
- water and other drinks;
- chewing gum;
- substances used as ingredients in
the preparation of food.