Because cooking ground beef renders the fat it contains into liquid, and that liquid typically remains in the pan or is drained away and does not stay with the beef, the beef's total volume reduces when cooked. One pound of raw ground beef, 85 percent lean or leaner, yields approximately 3 cups of cooked ground beef crumbles. Ground beef containing a higher percentage of fat yields slightly less because the fat will cook and drain away. One pound of raw ground beef -- 16 ounces -- yields only 12 ounces of cooked ground beef, or 3/4 pound.