Preheat the oven to 325°F and prepare a loaf pan using cooking spray.
In a large skillet, sauté the onion, zucchini, mushrooms and garlic for about five minutes. Season with salt and pepper and allow to cool slightly.
In a large bowl, mix together the turkey, the cooked vegetables, parsley, Worcestershire sauce, breadcrumbs and egg until combined.
Place the meat mixture into a loaf pan or alternately, form the mixture into a loaf and place on a prepared baking dish.
Mix together the ketchup and brown sugar and brush over the loaf. Make the meatloaf for one hour and 20 minutes or until a thermometer inserted reaches a temperature of 160°F.
Allow the meatloaf to cool for five minutes before slicing and serving.