Before the Song Dynasty, ordinary people could only eat two meals a day, only the royal family was entitled to eat four meals, and the princes ate three meals. In the Western Han Dynasty, in the imperial edict to the exiled king of Huainan for rebellion, it was pointed out that "reducing three meals a day to two meals" was a good proof that the princes ate three meals.
Before the Qin and Han Dynasties, due to underdeveloped agriculture and limited food, even two meals should be treated as people.
Mozi Miscellaneous Harvest says that soldiers have two meals a day, and their food intake is divided into five categories. The first meal is when the sun goes to the southeast. The second meal is about four o'clock in the afternoon.
For the time of eating, the ancients said that "food is irregular" (The Analects of Confucius). Eating when you shouldn't eat is considered as a polite behavior or a special reward.
Due to the economic prosperity in the Song Dynasty, restaurants were no longer confined to the middle of the market as in the Tang Dynasty, and night markets did not impose curfews at night. At night, nightlife became rich, and people stayed up late. They were easily hungry at night, so they added a New Year's Eve dinner. Therefore, three meals began to be called breakfast, lunch and dinner.
As for four meals a day, it belonged to "imperial diet" in ancient times and was institutionalized in Han Dynasty. China's ancient food system has obvious hierarchical color and etiquette characteristics, so the emperor's food arrangement is naturally different, and "don't be condescending" shall prevail.
It turns out that the emperor ate four meals a day by borrowing the digital concept of "four directions" and "four seasons", which is superstition. In contrast, our modern life is simply wonderful, with six meals and seven meals a day. It's an imperial life.