Liu Heng’s “Dogshit Food” and Yan Lianke’s Serve the People

What is the relationship between food and/or sex in texts such as Liu Heng’s “Dogshit Food” and Yan Lianke’s Serve the People? What do food and/or sex mean in these texts – basic need for survival or something else? With the focus on food and/or sex, what other aspects of life in China during the Mao era have the texts chosen to comment on ?