Heat oven to 350°F. Lightly oil shallow 12 x 8 x 2-inch baking pan.
Place large nonstick skillet over high heat. Add the 1 teaspoon vegetable oil; swirl to coat. Add coleslaw mix; brown well without stirring, about 3 minutes. Cook, stirring, 2 minutes longer, adding 2 tablespoons water after 1 minute. Let cool slightly.
Crumble beef and pork into large bowl. Add browned vegetables, egg whites, bread crumbs, tomatoes, celery salt and pepper. Shape into loaf in bowl; place in prepared pan. Reshape into 10 x 5-inch loaf.
Bake in 350°F oven 1 hour or until internal temperature reaches 160°F. Drain off drippings; reserve for Good Gravy (recipe follows). Let meat loaf stand 10 minutes before slicing.