This can be as simple as a butcher preparing meat, or as complex as a modern international food industry.

this指代前面句子的内容。主干为主系表结构： This can be simple or complex.  二个表语形容词分别被as...as结构修饰。第二个as引导比较状语从句。as simple as a butcher preparing meet (is), a butcher preparing meet为动名词复合结构作as从句的主语，is省略了。as complex as a modern international food industry (is) , as从句主语为名词词组，is省略了。