Carnitine Vegan Diets Sources Supplements & Deficiency L carnitina para mejor rendimiento y para quemar la grasa Blog Steak isn't bleeding. That red liquid you see is mostly water mixed with myoglobin, a protein found in muscle that stores oxygen. When steak cooks, the muscle fibers tighten and release moisture. Beef Benefits (Why is Beef Healthy?) Data Driven Science IMPORTANCE OF BEEF Beef is an important part of a healthy diet. It contains a fair amount of fat, but it is also a concentrated source of protein, vitamins, and minerals.