From Academic Kids
A staple food is a basic but nutritious food that forms the basis of a traditional diet, particularly that of the poor. 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. Staple foods vary from place to place, but are usually of vegetable origin, from cereals, pulses, rice, millets and plants growing starchy roots. Bread, noodles (or pasta), rice congee and porridge are prepared from them.
Types of bread that are considered staples in some parts of the world:
Staple crops harvested for their starchy underground storage organ:
It has been hypothesised that some staple foods may act as a Giffen good in conditions of extreme poverty.