Human nutrition
The protein requirement for each individual differs, as do opinions about whether and to what extent physically active people require more protein. The 2005 Recommended Dietary Allowances (RDA), aimed at the general healthy adult population, provide for an intake of 0.8 grams of protein per kilogram of body weight. A review panel stating that "no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise."
Beef
Beef is a source of complete protein and it is a rich source (20% or more of the Daily Value, DV) of Niacin, Vitamin B12, iron and zinc. Red meat is the most significant dietary source of carnitine and, like any other meat (pork, fish, veal, lamb etc.), is a source of creatine. Creatine is converted to creatinine during cooking.Excessive consumption of red processed meat is known to increase the risk of bowel cancer and some other cancers.The Harvard School of Public Health recommends consumers eat red meat sparingly as it has high levels of undesirable saturated fat. This recommendation is not without controversy, though. Another study from The Harvard School of Public Health appearing in Circulation (journal) found "Consumption of processed meats, but not red meats, is associated with higher incidence of coronary heart disease and diabetes mellitus."