Preheat oven to 350°.
Combine first 8 ingredients in a large bowl, tossing to moisten bread. Crumble meat over onion mixture, and stir just until blended. Pack mixture into a 9 x 5-inch loaf pan coated with cooking spray. Spread ketchup over top of loaf. Bake at 350° for 1 hour or until meat loaf registers 160°. Let loaf stand in pan 10 minutes.
Remove meat loaf from pan; cut loaf into 6 slices.
Sandwich suggestion: Serve leftover slices on whole-wheat bread with mayonnaise, lettuce, and cheddar cheese.