Human constitutions are divided into cold and hot types, and so are foods. Generally, one can determine their nature as cold or hot based on their color, taste, growth environment, geographical location, and season of growth.
Based on color: Foods with a greenish hue tend to be cold in nature, while those with a reddish hue tend to be warm. Green plants grow close to the ground, absorbing its moisture, hence they are considered cold, such as mung beans and green leafy vegetables. Plants that are reddish in color, like chili peppers, jujubes, and pomegranates, although they also grow close to the ground, their fruits absorb more sunlight, making them hot in nature.
Based on taste: Foods that are bitter or sour in taste are cold in nature, while those that are sweet or pungent are hot. Bitter and sour foods, such as bitter melon, endive, taro, plums, and papayas, are considered cold. Pungent and sweet foods, having been exposed to sunlight for longer periods, are hot, like garlic, persimmons, and pomegranates.
Based on the growth environment: Aquatic plants tend to be cold, while terrestrial plants tend to be hot. Lotus root, kelp, and seaweed are considered cold. Foods that grow on land, such as peanuts, potatoes, Chinese yams, and ginger, have less moisture as they are grown in the soil, hence they are hot in nature.
Based on sunlight exposure: Foods that grow in the shade are cold, while those that grow in the sun are hot. Shade-loving plants that face north absorb more moisture and see little sunlight, so they are cold, such as mushrooms and wood ear mushrooms. Foods that grow in the open or have a tendency towards the sun, like sunflowers and chestnuts, receive ample sunlight and are therefore hot in nature.
Based on the season: Foods that grow in winter and summer are cold, while those that grow in spring and autumn are hot. Foods that grow in winter are cold in nature due to the heavy coldness in the air, such as Chinese cabbage, shiitake mushrooms, white radish, and winter melon. Foods that grow in summer are also cold because they receive more rainfall, such as watermelon, cucumber, and pear. Foods from spring and autumn, like apples and oranges, are generally hot in nature.