the principle primarily concerns the "heating" and "cooling" properties of ingredients. Certain dishes are served in their respective seasons to provide contrasts in temperature and spiciness of the food and environment. Some examples are: Duck meat, considered "cool", is served during the hot summer with ginger fish sauce, which is "warm". Conversely, chicken, which is "warm", and pork, which is "hot", are eaten in the winter. Seafoods ranging from "cool" to "cold" are suitable to use with ginger ("warm"). Spicy foods ("hot") are typically balanced with sourness, which is considered "cool". Balut (), meaning "upside-down egg" ("cold"), must be combined with Vietnamese mint () ("hot"). Food in relation to lifestyle Vietnamese cuisine is reflective of the Vietnamese lifestyle, from the preparation to how the food is served. Going through long phases of war and political conflict, as well as cultural shifts, the vast majority of the Vietnamese people have been living in poverty. Therefore, the ingredients for Vietnamese food are often very inexpensive but nonetheless, the way they are cooked together to create a yin–yang balance makes the food simple in appearance but rich in flavor. Because of economic conditions, maximizing the use of ingredients to save money has become a tradition in Vietnamese cooking. In earlier decades and even nowadays in rural areas, every part of a cow is used, from the muscle meat to the intestines; nothing is wasted. The higher quality cuts from farmed animals (cows, pigs) would be cooked in stirfry, soup or other dishes, while the secondary cuts would be used in blood sausages or soup. The same goes for vegetables like scallions: the leafy part is diced into small bits which are used to add flavor to the food while the crunchy stalk and roots are replanted. (fish sauce) is the most commonly used and iconic condiment in Vietnamese cooking. It is made from fermented raw fish and is served with most of the Vietnamese dishes. Vietnamese cuisines are not known for ingredients with top quality, but rather for the very inexpensive and simple scraps that are creatively mixed to create dishes with bold flavor. A traditional southern Vietnamese meal usually includes (plain white rice), (catfish in a clay pot), (sour soup with snakehead fish), and it would be incomplete without fish sauce served as a condiment. Dishes are prepared less with an appearance in mind but are served family-style to bring everyone together