Preheat the oven to 350 degrees F.
In a 12-inch nonstick skillet, heat the oil over medium heat. Add the celery and onions and cook until tender, about 10 minutes, stirring occasionally. Add the garlic and cook 1 minute. Transfer the vegetables to a large bowl and cool slightly.
Add the turkey, breadcrumbs, milk, Worcestershire sauce, 1/4 cup ketchup, salt, pepper and egg whites to the vegetables. Mix with hands until well combined, but do not over mix. In a cup, combine the Dijon and remaining 1/4 cup ketchup.
In a 9-by-13-inch metal baking pan, shape the meat mixture into a 9-by-5-inch loaf. (This will allow the meat loaf to brown all over, not just on top.) Spread the ketchup mixture over the top of the loaf.
Bake the meat loaf until an instant-read meat thermometer inserted in the center reaches 160 degrees F, 55 to 60 minutes. (Temperature will rise to 165 degrees F upon standing.)
Let the meat loaf stand 10 minutes to set the juices for easier slicing before removing from the pan. Transfer the meat loaf to a platter and serve.