Cui Xiaotian, Zhao Jinzhao, Zhou Xinda, Hua Ang, Chengxi, Tan Chen, and Han Wei Liu Ping, a 25-year-old living in Beijing, is queuing up outside the obesity clinic of the Peking University People’s Hospital early one morning, seeking a doctor’s prescription for the so-called “skinny jab” — a weight loss drug that has created a buying frenzy in China, where half the adults out of a total population of 1.4 billion are either overweight or obese.