Why does China rely heavily on imported food products?

A large part of China’s reliance on imported food products stems from four major issues within the country.  First off, China is the most populous nation on earth, and only 11% of China’s land is suitable for farming.  The second reason is that 20% of China’s land and 40% of its rivers are polluted, further limiting its ability to produce foodstuffs within its borders.  This well-known fact contributes to the third reason, which is that many Chinese worry over the quality of domestic food products.  Various food scandals have played a role in driving Chinese consumers towards foreign products in the industry.  The last reason is a growing appetite for foreign cuisine, which has been made increasingly attainable by the nation’s steady economic growth.