Preheat oven to 350 degrees. Spray a 4-1/2 x 8-1/2-inch loaf pan with cooking spray.
Heat the oil in a large nonstick skillet on medium high heat. Add onion, carrot and celery. Stir and cook for 5 minutes, until vegetables begin to wilt. Remove from heat and leave in the pan.
Mix the ground beef, bread crumbs, egg, 1/4 cup of the ketchup (reserving the remaining 1/2 cup for the top) in a large bowl. Add 1 T. Worcestershire sauce, the seasonings and the cooked vegetables with the oil. Stir well with wooden spoon.
Pour into the prepared pan and pat down to form a loaf. Mix the remaining ketchup and Worcestershire sauce and pour over top. Cook uncovered for 45 minutes.
When meat loaf is cooked, spoon off any grease in pan and let sit for 5 minutes before slicing.