There seem to be lots of studies out there saying red meat (beef) directly causes cancer, for example:
Sinha, R. et al. “Well-done, grilled red meat increases the risk of colorectal adenomas.” Cancer Research 59.17 (1999): 4320.
Giovannucci E., Rimm E. B., Stampfer M. J., Colditz G. A., Ascherio A., Willet W. C. Intake of fat, meat and fiber in relation to risk of colon cancer in men. Cancer Res., 54: 2390-2397, 1994.
Willet W. C., Stampfer M. J., Colditz G. A., Rosner B. A., Speizer F. E. Relation of meat, fat and fiber intake to the risk of colon cancer in a prospective study among women. N. Engl. J. Med., 323: 1664-1672, 1990.
Kune, Gabriel A. “The Melbourne Colorectal Cancer Study: reflections on a 30-year experience.” The Medical Journal of Australia 193.11-12 (2010): 648-652.
Tavani, A. et al. “Red meat intake and cancer risk: a study in Italy.” International Journal of Cancer 86.3 (2000): 425-428.
On a more personal note, my dad used to eat steak almost every day in his 20s, and he developed colon cancer in his late 40s. His surgeon told him it was directly a result of all the red meat he ate. Now he avoids red meat like the plague.
Various studies also consider bacon to be red meat.
What is the primal community response to this?