Beat together eggs, egg whites, milk, salt and pepper. Set aside. Heat olive oil in a 10-12 inch non-stick skillet. Add the onion, red pepper, zucchini, and parsley. Gently cook for about 4 to 5 minutes stirring frequently. Add the tomato and stir well. Cook for about 5 minutes. Pour egg mixture over the vegetables. Turn heat to low and cover. Cook for about 10 minutes checking periodically to see if eggs are firm. When done, run a rubber spatula around edge of frittata, cut into four wedges and serve. Makes 4 servings.