A staple food is a food that forms the basis of a traditional diet. Staple foods vary from place to place, but are typically inexpensive starchy foods of vegetable origin that are high in food energy (Calories) and carbohydrate and that can be stored for use throughout the year. The staple food of a specific cuisine may commonly be served as part of every meal, and its name may be used synonymously with "food" in some contexts, such as the reference to "our daily bread" in The Lord's Prayer, and a common greeting of "Have you eaten rice?" denoting "How are you?" in certain cultures.
Most staple foods derive either from cereals such as wheat, barley, rye, maize, or rice, or starchy root vegetables such as potatoes, yams, taro, and cassava. Other staple foods include pulses (dried legumes), sago (derived from the pith of the sago palm tree), and fruits such as breadfruit and plantains.
Rice is most commonly eaten as cooked entire grains, but most other cereals are milled into flour or meal which is used to make bread; noodles or other pasta; and porridges and "mushes" such as polenta or mealie pap. Mashed root vegetables can be used to make similar porridge-like dishes, including poi and fufu. Pulses (particularly chickpeas) and starchy root vegetables, such as Canna, can also be made into flour.
Although nutritious, staple foods generally do not by themselves provide a full range of nutrients, so other foods need to be added to the diet to prevent malnutrition. For example, the deficiency disease pellagra is associated with a diet consisting primarily of maize, and beriberi with a diet of white (i.e. refined) rice.
It has been hypothesized that some staple foods may act as a Giffen good in conditions of extreme poverty. This was first noted by Robert Giffen who argued that potato demand actually rose during the Great Irish Famine (1845-1849). While theoretically possible, this is a controversial view among economists as studies have failed to find much evidence of Giffen good behaviour in actual markets.