A population successful in an ecological niche must have a dietary pattern that provides the minimum requirements of all 40–45 essential nutrients, in addition to the energy sources—carbohydrates, fat, and protein. Cereal production and its contribution to diets in developing countries exceed that of legumes and roots, tubers, plantains and bananas. Legumes are highest in protein and is rich in lysine but deficient in cystine and methionine. Cereals are intermediate in protein content; their protein is rich in cystine and methionine but deficient in lysine. Thus cereal‐legume diets have a better amino acid balance than either diet alone, as shown by the high protein quality of most composite diets. Storage proteins are prolamin and glutelin in cereal endosperm, but globulin in legume cotyledon, occurring as prolamin protein body (PB) in cereals and globulin PB in legumes. Glutelin PB occurs in rice endosperm. Roots, tubers, plantains and bananas are high in moisture, hence, poor in protein content and other nutrients and have a poor postharvest shelf life. Potato protein has a balanced amino acid composition. Antinutrition factors for protein include protease (trypsin) inhibitor, tannins, and phytate.