Meat is animal flesh prepared for human consumption and consumed as food. Most often, the meat consumed by humans is the meat of pigs, cattle, lambs or other mammals. The word meat comes from Old English mete, which means food. Meat is generally classified as red or white, depending on the concentration of myoglobin in the flesh, or more specifically - muscle fiber. Chicken and turkey breast meat, for example, is considered white. Meat has been part of the human diet in most cultures since prehistoric times. However, many people do not consume meat due to ethical objections to the slaughter of animals.