 Indigenous peoples in western Mexico began to selectively breed maize ("Zea mays") plants from precursor grasses (e.g., teosinte) between 5,000 and 10,000 years ago.The diet of ancient central and southern Mexico was varied, including domesticated corn (or maize), squashes such as pumpkin and butternut squash, common beans (pinto, kidney, navy and other common beans consumed today), tomatoes, peppers, cassavas, pineapples, chocolate, and tobacco.The Three Sisters (corn, squash, and beans) constituted the principal diet.