Cook onion and garlic in oil over moderate heat, until onion is soft. Add carrot and cook. Add mushrooms, 1/2 tsp salt, and 1/4 tsp pepper and cook until liquid is evaporated. Stir in Worcestershire, parsley, and 3 T ketchup, put in a large bowl and cool. Stir bread crumbs and milk in a bowl and let stand 5 minutes. Stir in egg and egg white, then add to vegetables. Add turkey and remaining 1/2 tsp salt and 1/4 tsp pepper to vegetable mixture and mix well with your hands. (Mixture will be very moist.) Form into loaf in a lightly oiled 13- by 9- by 2-inch metal baking pan and brush meatloaf evenlywith remaining 2 T ketchup. Bake at 350F until meat thermometer registers 170F, 50 to 55 minutes. Each (app 1 cup) serving contains an estimated: Cals: 221, FatCals: 69, TotFat: 8g SatFat: 2g, PolyFat: 2g, MonoFat: 4g Chol: 87mg, Na: 700mg, K: 533mg TotCarbs: 19g, Fiber: 3g, Sugars: 4g NetCarbs: 16g, Protein: 19g