1 to 1 1/2 pounds beef stew meat, cut into 1-inch cubes 2 tablespoons cooking oil 6 cups water 2 or 3 large potatoes, peeled and cut into 1-inch cubes 3 to 4 medium carrots, sliced 1 large green pepper, cut into 1/2-inch pieces 1 large tomato, cut into 1/2-inch pieces 4 to 8 ounces mushrooms, cut into 1/2-inch pieces 4 garlic cloves, minced 1 medium onion, chopped 2 teaspoons salt 1/4 teaspoon pepper