Nattō (納豆, Nattō) is a traditional Japanese food made from fermented soybeans, popular especially for breakfast. As a rich source of protein, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan. For some, nattō can be an acquired taste due to its powerful smell, strong flavor, and sticky consistency. In Japan nattō is most popular in the eastern regions, including Kantō, Tōhoku, and Hokkaido.