Staple foods vary from place to place, but typically they are inexpensive or readily-available foods that supply one or more of the three organic macronutrients needed for survival and health: carbohydrates, proteins, and fats. Typical examples of staples include tubers and roots; and grains, legumes, and other seeds. Early agricultural civilizations valued the foods that they established as staples because, in addition to providing necessary nutrition, they generally are suitable for storage over long periods of time without decay. Such nonperishable foods are the only possible staples during seasons of shortage, such as dry seasons or cold temperate winters, against which times harvests have been stored. During seasons of plenty, wider choices of foods may be available.
Main staple foods are derived either from vegetables or animal products, and include cereals (such as rice, wheat, maize, millet, or sorghum), starchy tubers or root vegetables (such as potatoes, cassava, yams, or taro), meat, fish, eggs, milk, and cheese. Other staple foods include pulses (dried legumes), sago (derived from the pith of the sago palm tree), and fruits (such as breadfruit and plantains). Staple foods may also contain (depending on the region): olive oil, coconut oil and sugar (e.g., from plantains).
Of the more than 50,000 edible plant species in the world, only a few hundred contribute significantly to human food supplies. Although there are over 10,000 species in the cereal family, just a few have been widely cultivated over the past 2,000 years.
The staple food in different parts of the world is a function of weather patterns, local terrain, farming constraints, acquired tastes and ecosystems. For example, the main energy source staples in the average African diet are cereals (46 percent), roots and tubers (20 percent) and animal products (seven percent). In Western Europe the main staples in the average diet are animal products (33 percent), cereals (26 percent), and roots and tubers (four percent).
Most of the global human population lives on a diet based on one or more of the following staples: rice, wheat, maize (corn), millet, sorghum, roots and tubers (potatoes, cassava, yams and taro), and animal products such as meat, milk, eggs, cheese and fish. Regional staples include rye, soybeans, barley, oats, and teff.
Just 15 crop plants provide 90 percent of the world's food energy intake (exclusive of meat), with rice, maize, and wheat comprising two-thirds of human food consumption. The three are the staples of about 80 percent of the world population, and rice feeds almost half of humanity.
Roots and tubers, meanwhile, are important staples for over one billion people in the developing world, accounting for roughly 40 percent of the food eaten by half the population of sub-Saharan Africa. Roots and tubers are high in carbohydrates, calcium, and vitamin C, but low in protein. Cassava root is a major staple food in the developing world, providing a basic diet for around 500 million people.