Jilin people. Zheng is a professor of nutrition, a public nutritionist, a health manager and a non-drug rehabilitation expert for chronic diseases in a large 3A hospital in Beijing. He explained the nutrition knowledge in the live class, and his friend Liu Dajun was also mentioned in the live room. He is a native of Jilin and his ancestral home is Tangshan, Hebei. A friend refers to a person whose interpersonal relationship has developed to be irrelevant but very friendly.