Food is any substance consumed by an
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
for
nutritional
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficien ...
support. Food is usually of
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
,
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
, or
fungal
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from th ...
origin, and contains essential
nutrient
A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s, such as
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
s,
fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers spec ...
s,
proteins
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
,
vitamin
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an Nutrient#Essential nutrients, essential micronutrient that an organism needs in small quantities for the proper functioning of its ...
s, or
minerals
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
. The substance is
ingested
Ingestion is the consumption of a substance by an organism. In animals, it normally is accomplished by taking in a substance through the mouth into the gastrointestinal tract, such as through eating or drinking. In single-celled organisms inges ...
by an organism and assimilated by the organism's
cells to provide
energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat a ...
, maintain life, or stimulate growth. Different species of animals have different
feeding behaviours that satisfy the needs of their unique
metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
s, often evolved to fill a specific
ecological niche
In ecology, a niche is the match of a species to a specific environmental condition.
Three variants of ecological niche are described by
It describes how an organism or population responds to the distribution of resources and competitors (for ...
within specific geographical contexts.
Omnivorous
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...
humans are highly adaptable and have adapted to obtain food in many different ecosystems. The majority of the
food energy
Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscle, muscular activity.
Most animals derive most of their energy from aerobic respiration, namely combining the ...
required is supplied by the industrial
food industry
The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the world's population. The food industry today has become highly diversified, with manufacturing ranging from small, traditiona ...
, which produces food with
intensive agriculture
Intensive agriculture, also known as intensive farming (as opposed to extensive farming), conventional, or industrial agriculture, is a type of agriculture, both of crop plants and of animals, with higher levels of input and output per unit of ag ...
and distributes it through complex
food processing
Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing includes many forms of processing foods, from grinding grain to make raw flour to home cooking to complex industr ...
and
food distribution
Food distribution is the process where a general population is supplied with food. The Food and Agriculture Organization (FAO) considers food distribution as a subset of the food system. The process and methodology behind food distribution varies ...
systems. This system of conventional agriculture relies heavily on
fossil fuel
A fossil fuel is a hydrocarbon-containing material formed naturally in the Earth's crust from the remains of dead plants and animals that is extracted and burned as a fuel. The main fossil fuels are coal, oil, and natural gas. Fossil fuels m ...
s, which means that the food and agricultural system is one of the
major contributors to climate change, accountable for as much as 37% of total
greenhouse gas emissions
Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and lar ...
.
The food system has significant impacts on a wide range of other social and political issues including:
sustainability
Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...
,
biological diversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') lev ...
,
economics
Economics () is the social science that studies the Production (economics), production, distribution (economics), distribution, and Consumption (economics), consumption of goods and services.
Economics focuses on the behaviour and intera ...
,
population growth
Population growth is the increase in the number of people in a population or dispersed group. Actual global human population growth amounts to around 83 million annually, or 1.1% per year. The global population has grown from 1 billion in 1800 to ...
,
water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...
, and
access to food.
Food safety
Food safety (or food hygiene) is used as a scientific method/discipline describing handling, preparation, and storage of food in ways that prevent food-borne illness. The occurrence of two or more cases of a similar illness resulting from t ...
and
food security
Food security speaks to the availability of food in a country (or geography) and the ability of individuals within that country (geography) to access, afford, and source adequate foodstuffs. According to the United Nations' Committee on World F ...
are monitored by international agencies like the
International Association for Food Protection
The International Association for Food Protection (IAFP), founded in 1911, is a non-profit association of food safety professionals based in Des Moines, Iowa. The organization claims a membership of over 3,000 members from 50 nations. The missi ...
,
World Resources Institute
The World Resources Institute (WRI) is a global research non-profit organization established in 1982 with funding from the MacArthur Foundation under the leadership of James Gustave Speth. WRI's activities are focused on seven areas: food, fore ...
,
World Food Programme
The World Food Programme; it, Programma alimentare mondiale; es, Programa Mundial de Alimentos; ar, برنامج الأغذية العالمي, translit=barnamaj al'aghdhiat alealami; russian: Всемирная продовольствен ...
,
Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
, and
International Food Information Council
Founded in 1985, the International Food Information Council (IFIC) is a nonprofit organization supported by the food, beverage, and agricultural industries.
According to the Center for Media and Democracy, "In reality, IFIC is a public relations ...
.
Definition and classification
Food is any substance consumed to provide
nutritional
Nutrition is the biochemical and physiological process by which an organism uses food to support its life. It provides organisms with nutrients, which can be metabolized to create energy and chemical structures. Failure to obtain sufficien ...
support and energy to an
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
.
It can be raw, processed or formulated and is consumed orally by animals for growth, health or pleasure. Food is mainly composed of water,
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
s,
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s and
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
s.
Mineral
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...
s (e.g. salts) and organic substances (e.g.
vitamin
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an Nutrient#Essential nutrients, essential micronutrient that an organism needs in small quantities for the proper functioning of its ...
s) can also be found in food. Plants,
algae
Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mic ...
and some microorganisms use
photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
to make their own food molecules. Water is found in many foods and has been defined as a food by itself. Water and
fiber
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
have low energy densities, or
calorie
The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of on ...
s, while fat is the most energy dense component.
Some inorganic (non-food) elements are also essential for plant and animal functioning.
Human food can be classified in various ways, either by related content or by how the food is processed. The number and composition of
food group
A food group is a collection of foods that share similar nutritional properties or biological classifications. List of nutrition guides typically divide foods into food groups and Recommended Dietary Allowance recommend daily servings of each gr ...
s can vary. Most systems include four basic groups that describe their origin and relative nutritional function: Vegetables and Fruit, Cereals and Bread, Dairy, and Meat. Studies that look into diet quality often group food into whole grains/cereals, refined grains/cereals, vegetables, fruits, nuts, legumes, eggs, dairy products, fish, red meat, processed meat, and sugar-sweetened beverages. The
Food and Agriculture Organization
The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...
and
World Health Organization
The World Health Organization (WHO) is a specialized agency of the United Nations responsible for international public health. The WHO Constitution states its main objective as "the attainment by all peoples of the highest possible level of h ...
use a system with nineteen food classifications: cereals, roots, pulses and nuts, milk, eggs, fish and shellfish, meat, insects, vegetables, fruits, fats and oils, sweets and sugars, spices and condiments, beverages, foods for nutritional uses, food additives, composite dishes and savoury snacks.
Food sources
In a given ecosystem, food forms a
web
Web most often refers to:
* Spider web, a silken structure created by the animal
* World Wide Web or the Web, an Internet-based hypertext system
Web, WEB, or the Web may also refer to:
Computing
* WEB, a literate programming system created by ...
of interlocking
chains
A chain is a serial assembly of connected pieces, called links, typically made of metal, with an overall character similar to that of a rope in that it is flexible and curved in compression but linear, rigid, and load-bearing in tension. A c ...
with
primary producers
An autotroph or primary producer is an organism that produces complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide,Morris, J. et al. (2019). "Biology: How Life Work ...
at the bottom and
apex predator
An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own.
Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...
s at the top.
Other aspects of the web include
detrovores (that eat
detritis) and
decomposer
Decomposers are organisms that break down dead or decaying organisms; they carry out decomposition, a process possible by only certain kingdoms, such as fungi. Like herbivores and predators, decomposers are heterotrophic, meaning that they use o ...
s (that break down dead organisms).
Primary producers include algae, plants, bacteria and protists that acquire their energy from sunlight. Primary consumers are the herbivores that consume the pants and secondary consumers are the carnivores that consume those herbivores. Some organisms, including most mammals and birds, diets consist of both animals and plants and they are considered omnivores.
The chain ends with the apex predators, the animals that have no known predators in its ecosystem. Humans are often considered apex predators.
Humans are omnivores finding sustenance in vegetables, fruits, cooked meat, milk, eggs, mushrooms and seaweed.
Cereal
A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...
grain is a
staple food
A staple food, food staple, or simply a staple, is a food that is eaten often and in such quantities that it constitutes a dominant portion of a standard diet for a given person or group of people, supplying a large fraction of energy needs and ...
that provides more food energy worldwide than any other type of crop.
Corn (maize)
Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...
,
wheat
Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...
, and
rice
Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima
''Oryza glaberrima'', commonly known as African rice, is one of the two domesticated rice species. It was first domesticated and grown i ...
account for 87% of all grain production worldwide.
Just over half of the worlds crops are used to feed humans (55 percent), with 36 percent grown as animal feed and 9 percent for
biofuels
Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration (E ...
. Fungi and bacteria are also used in the preparation of
fermented
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
foods like bread, wine,
cheese
Cheese is a dairy product produced in wide ranges of flavors, textures, and forms by coagulation of the milk protein casein. It comprises proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. During production, ...
and
yogurt
Yogurt (; , from tr, yoğurt, also spelled yoghurt, yogourt or yoghourt) is a food produced by bacterial Fermentation (food), fermentation of milk. The bacteria used to make yogurt are known as ''yogurt cultures''. Fermentation of sugars in t ...
.
Sunlight
Photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
is the ultimate source of energy and food for nearly all life on earth. It is the main food source for plants, algae and certain bacteria. Without this all organisms which depend on these organisms further up the food chain would be unable to exist, from coral to lions. Energy from the sun is absorbed and used to transform water and carbon dioxide in the air or soil into oxygen and glucose. The oxygen is then released and the glucose stored as an energy reserve.
Plants
Plants as a food source are often divided into seeds, fruits, vegetables, legumes, grains and nuts.
Where plants fall within these categories can vary with botanically described fruits such as the tomato, squash, pepper and eggplant or seeds like peas commonly considered vegetables. Food is a fruit if the part eaten is derived from the
reproductive tissue, so seeds, nuts and grains are technically fruit.
From a culinary perspective fruits are generally considered the remains of botanically described fruits after grains, nuts, seeds and fruits used as vegetables are removed.
Grains can be defined as seeds that humans eat or harvest, with cereal grains (oats, wheat, rice, corn, barley, rye, sorghum and millet) belonging to the
Poaceae
Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...
(grass) family and pulses coming from the
(legume) family.
Whole grain
A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm.
As part of a general healthy diet, consumption of whole grains is associated w ...
s are foods that contain all the elements of the original seed (bran, germ, and
endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...
). Nuts are dry fruits distinguishable by their woody shell.
Fleshy fruits (distinguishable from dry fruits like grain, seeds and nuts) can be further classified as
stone fruits (cherries and peaches),
pome fruits (apples, pears),
berries
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...
(blackberry, strawberry),
citrus
''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...
(oranges, lemon),
melon
A melon is any of various plants of the family Cucurbitaceae with sweet, edible, and fleshy fruit. The word "melon" can refer to either the plant or specifically to the fruit. Botanically, a melon is a kind of berry, specifically a "pepo". The ...
s (watermelon, cantaloupe), Mediterranean fruits (grapes, fig),
tropical fruits
A tropical fruit one that typically grows in warm climates, or equatorial areas.
Tropical fruits
Varieties of tropical fruit include:
*Acerola ( West Indian Cherry or Barbados Cherry)
*Ackee
*Banana
*Barbadine (granadilla; maracujá-açu in ...
(banana, pineapple).
Vegetables refer to any other part of the plant that can be eaten, including roots, stems, leaves, flowers, bark or the entire plant itself.
These include
root vegetable
Root vegetables are underground plant parts eaten by humans as food. Although botany distinguishes true roots (such as taproots and tuberous roots) from non-roots (such as bulbs, corms, rhizomes, and tubers, although some contain both hypocotyl a ...
s (
potato
The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae.
Wild potato species can be found from the southern Unit ...
es and
carrot
The carrot ('' Daucus carota'' subsp. ''sativus'') is a root vegetable, typically orange in color, though purple, black, red, white, and yellow cultivars exist, all of which are domesticated forms of the wild carrot, ''Daucus carota'', nat ...
s), bulbs (
onion
An onion (''Allium cepa'' L., from Latin ''cepa'' meaning "onion"), also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus ''Allium''. The shallot is a botanical variety of the onion ...
family), flowers (cauliflower and broccoli),
leaf vegetable
Leaf vegetables, also called leafy greens, pot herbs, vegetable greens, or simply greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Leaf vegetables eaten raw in a salad can be called salad gre ...
s (
spinach
Spinach (''Spinacia oleracea'') is a leafy green flowering plant native to central and western Asia. It is of the order Caryophyllales, family Amaranthaceae, subfamily Chenopodioideae. Its leaves are a common edible vegetable consumed either f ...
and
lettuce
Lettuce (''Lactuca sativa'') is an annual plant of the family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce is most often used for salads, although it is also seen in other kinds of food, ...
) and
stem vegetables
Stem or STEM may refer to:
Plant structures
* Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang
* Stipe (botany), a stalk to support some other structure
* Stipe (mycology), the stem of a mush ...
(celery and
asparagus
Asparagus, or garden asparagus, folk name sparrow grass, scientific name ''Asparagus officinalis'', is a perennial flowering plant species in the genus ''Asparagus''. Its young shoots are used as a spring vegetable.
It was once classified in ...
).
Plants have high
carbohydrate
In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...
,
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
and
lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...
content, with carbohydrates mainly in the form of starch, fructose, glucose and other sugars.
Most vitamins are found from plant sources, with the notable exceptions of
vitamin D
Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
and
vitamin B12.
Minerals
In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...
are also plentiful, although the presence of
phytates can prevent their release.
Fruit can consist of up to 90% water, contain high levels of
simple sugars
Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built.
They are usually colorless, water-solub ...
that contribute to their sweet taste and have a high
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
content.
Compared to fleshy fruit (excepting Bananas) vegetables are high in starch,
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
,
dietary fiber
Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...
,
folate
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and ...
and vitamins and low in fat and calories. Grains are more starch based
and nuts have a high protein, fibre, vitamin E and B content.
Seeds are a good source of food for animals because they are abundant and contain fibre and healthful fats, such as
omega-3 fats.
Animals that only eat plants are called
herbivore
A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...
s, with those that mostly just eat fruits known as
frugivore
A frugivore is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance an ...
s, leaves, while shoot eaters are
folivore
In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (1 ...
s (pandas) and wood eaters termed
xylophages (termites). Frugivores include a diverse range of species from annelids to elephants, chimpanzees and many birds. About 182 fish consume seeds or fruit. There are many types of grasses, adapted to different locations, that animals (domesticated and wild) use as their main source of nutrients.
Humans only eat about 200 out of the worlds 400 000 plant species, despite at least half of them being edible.
Most human plant-based food comes from maize, rice, and wheat.
Plants can be processed into breads, pasta, cereals, juices and jams or raw ingredients such as sugar, herbs, spices and oils can be extracted.
Oilseed
Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of fruits. Like animal fats, vegetable fats are ''mixtures'' of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fat ...
s are often pressed to produce rich oils -
sunflower
The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...
,
flaxseed
Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. Textiles made from flax are known in W ...
,
rapeseed
Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains a ...
(including
canola oil
Close-up of canola blooms
Canola flower
Rapeseed oil is one of the oldest known vegetable oils. There are both edible and industrial forms produced from rapeseed, the seed of several cultivars of the plant family Brassicaceae. Historically, i ...
) and
sesame
Sesame ( or ; ''Sesamum indicum'') is a flowering plant in the genus ''Sesamum'', also called benne. Numerous wild relatives occur in Africa and a smaller number in India. It is widely naturalized in tropical regions around the world and is cu ...
.
[McGee, Chapter 9.]
Many plants and animals have
coevolved
In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well ...
in such a way that the fruit is good source of nutrition to the animal who then excretes the seeds some distance away allowing greater dispersal. Even
seed predation
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores (seed predators) feed on the seeds of plants as a main or exclusive food source,Hulme, P.E. and Benkman, C.W. (2002) "Granivory", pp. 13 ...
can be mutually beneficial as some seeds can survive the digestion process. Insects are major eaters of seeds,
with ants being the only real seed dispersers. Birds, although being major dispersers, only rarely eat seeds as a source of food and can be identified by their thick beak that is used to crack open the seed coat. Mammals eat a more diverse range of seeds as they are able to crush harder and larger seeds with their teeth.
Animals
Animals are used as food either directly or indirectly. This includes meat, eggs, shellfish and dairy products like milk and cheese. They are an important source or protein and are considered complete proteins for human consumption as they contain all the essential amino acids that the human body needs.
One steak, chicken breast or pork chop contains about 30 grams of protein. One large egg has 7 grams of protein, a serving of cheese about 15 grams and 1 cup of milk about 8.
Other nutrients found in animal products include calories, fat, essential vitamins (including B12) and minerals (including zinc, iron, calcium, magnesium).
Food products produced by animals include
milk
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...
produced by
mammary glands
A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in prima ...
, which in many cultures is drunk or processed into
dairy product
Dairy products or milk products, also known as lacticinia, are food products made from (or containing) milk. The most common dairy animals are cow, water buffalo, nanny goat, and ewe. Dairy products include common grocery store food items in th ...
s (cheese, butter, etc.). In addition, birds and other animals lay
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
, which are often eaten, and
bees produce
honey
Honey is a sweet and viscous substance made by several bees, the best-known of which are honey bees. Honey is made and stored to nourish bee colonies. Bees produce honey by gathering and then refining the sugary secretions of plants (primar ...
, a reduced
nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
from flowers, which is a popular sweetener in many cultures. Some cultures blood as food, consume blood, sometimes in the form of blood sausage, as a thickener for sauces, or in a Curing (food preservation), cured, Salting (food), salted form for times of food scarcity, and others use blood in stews such as jugging, jugged hare.
Some cultures and people do not consume meat or animal food products for cultural, dietary, health, ethical, or ideological reasons. Vegetarians choose to forgo food from animal sources to varying degrees. Vegans do not consume any foods that are or contain ingredients from an animal source.
Taste perception
Animals, specifically humans, have five different types of tastes: sweet, sour, saltiness, salty, bitter (taste), bitter, and umami. As animals have Evolution, evolved, the tastes that provide the most energy (sugar and
fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers spec ...
s) are the most pleasant to eat while others, such as bitter (taste), bitter, are not enjoyable. Water, while important for survival, has no taste. Fats, on the other hand, especially saturated fats, are thicker and rich and are thus considered more enjoyable to eat.
Sweet
Generally regarded as the most pleasant taste, sweetness is almost always caused by a type of simple sugar such as glucose or fructose, or disaccharides such as sucrose, a molecule combining glucose and fructose.
[New Oxford American Dictionary] Complex carbohydrates are long chains and thus do not have the sweet taste. Artificial sweeteners such as sucralose are used to mimic the sugar molecule, creating the sensation of sweet, without the calories. Other types of sugar include raw sugar, which is known for its amber color, as it is unprocessed. As sugar is vital for energy and survival, the taste of sugar is pleasant.
The stevia plant contains a compound known as steviol which, when extracted, has 300 times the sweetness of sugar while having minimal impact on blood sugar.
Sour
Sourness is caused by the taste of acids, such as vinegar in alcoholic beverages. Sour foods include
citrus
''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...
, specifically lemons, Lime (fruit), limes, and to a lesser degree Orange (fruit), oranges. Sour is evolutionarily significant as it is a sign for a food that may have gone rancidity, rancid due to bacteria.
[States "having an acid taste like lemon or vinegar: she sampled the wine and found it was sour. (of food, esp. milk) spoiled because of fermentation." New Oxford American Dictionary] Many foods, however, are slightly acidic, and help stimulate the taste buds and enhance flavor.
Salty
Saltiness is the taste of alkali metal ions such as sodium and
potassium
Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...
. It is found in almost every food in low to moderate proportions to enhance flavor, although to eat pure salt is regarded as highly unpleasant. There are many different types of salt, with each having a different degree of saltiness, including sea salt, fleur de sel, kosher salt, mined salt, and grey salt. Other than enhancing flavor, its significance is that the body needs and maintains a delicate electrolyte balance, which is the kidney's function. Salt may be iodized, meaning iodine has been added to it, a necessary nutrient that promotes thyroid function. Some canned foods, notably soups or packaged broths, tend to be high in salt as a means of preserving the food longer. Historically salt has long been used as a meat preservative as salt promotes water excretion. Similarly, dried foods also promote food safety.
Bitter
Bitter (taste), Bitterness is a sensation often considered unpleasant characterized by having a sharp, pungent taste. Unsweetened dark chocolate, caffeine, lemon rind, and some types of fruit are known to be bitter.
Umami
Umami has been described as savory and is characteristic of broths and cooked meats. Foods that have a strong umami flavor include meats, shellfish, fish (including fish sauce and preserved fish such as maldive fish, sardines, and anchovies), tomatoes, mushrooms, hydrolyzed vegetable protein, meat extract, yeast extract, cheeses, and soy sauce.
See also
References
Sources
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*.
Further reading
* Collingham, E.M. (2011). ''The Taste of War: World War Two and the Battle for Food''
* Katz, Solomon (2003). ''The Encyclopedia of Food and Culture'', Scribner
* Nestle, Marion (2007). ''Food Politics: How the Food Industry Influences Nutrition and Health'', University Presses of California, revised and expanded edition,
* Mobbs, Michael (2012). ''Sustainable Food'' Sydney: NewSouth Publishing,
The Future of Food(2015). A panel discussion at the 2015 ''Digital Life Design (DLD)'' Annual Conference. "How can we grow and enjoy food, closer to home, further into the future? ''MIT Media Lab's'' Kevin Slavin hosts a conversation with food artist, educator, and entrepreneur Emilie Baltz, professor Caleb Harper from ''MIT Media Lab's'' CityFarm project, the Barbarian Group's Benjamin Palmer, and Andras Forgacs, the co-founder and CEO of ''Modern Meadow'', who is growing 'victimless' meat in a lab. The discussion addresses issues of sustainable urban farming, ecosystems, technology, food supply chains and their broad environmental and humanitarian implications, and how these changes in food production may change what people may find delicious ... and the other way around." Posted on the official YouTube Channel of ''Digital Life Design, DLD''
External links
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*
Food TimelineWikibooks CookbookFood BBC Radio 4 discussion with Rebecca Spang, Ivan Day and Felipe Fernandez-Armesto (''In Our Time'', 27 December 2001)
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Food watchlist articles