There is universal agreement that some Mesoamerican people practiced human sacrifice and cannibalism, but there is no scholarly consensus as to its extent. At one extreme, anthropologist Marvin Harris, author of Cannibals and Kings, has suggested that the flesh of the victims was a part of an aristocratic diet as a reward, since the Aztec diet was lacking in proteins. According to Harris, the Aztec economy would not support feeding slaves (the captured in war) and the columns of prisoners were "marching meat".