The reasons are as follows:

Eating mutton on the winter solstice can warm up the body to some extent, and eating mutton in winter means that the winter solstice has arrived this year, not only for this kind of food, but also to welcome the arrival of the winter solstice. Eating mutton and mutton soup on the winter solstice in Shandong Province of China is regarded as bringing some good luck to the family, so as to promote and eat at home in the coming year. The custom of eating mutton on the winter solstice spread earlier in China, starting in Sheng Xing as early as the time of Emperor Gaozu Liu Bang. According to legend, on the day of the winter solstice, after eating mutton cooked by a certain minister, Emperor Gaozu Liu Bang found it very delicious, and he did not praise it, which led to the custom of eating mutton on the winter solstice.