I read “Prolonged Meat Diets with a Study of Kidney Function and Ketosis” by Walter S. McClellan and Eugene F. Du Bois, Journal of Biological Chemistry (1930). The original paper that kicked off all the Atkins diet ideas. It made quite a point of the fact that the two men participating started off thinking that they'd like eating all meat, and quickly realizing that they began craving fat and organ meat to an extent that it ended up making up the majority of their diet.