Use ground meat that has some fat content for flavor, but not too much so the soup doesn’t have too much grease. Try for 10-15% fat. Usually, the lean to fat ratios in ground beef are: Ground chuck 80-85% lean to 15-20% fat, Ground round 85-90% lean to 10-15% fat, and Ground sirloin 90-92% lean to 8-10% fat.