Rice is a good source of protein and a staple food in many parts of the world, but it is not a complete protein: it does not contain all of the essential amino acids in sufficient amounts for good health, and should be combined with other sources of protein, such as nuts, seeds, beans, fish, or meat. The many varieties of rice, for many purposes, are distinguished as long, medium, and short grain rices. At right, traditional fried rice with grilled meat topped with an egg.