People in Asia eat rice. / People eat rice in Asia.
a. People in Asia eat rice.
b. People eat rice in Asia.
Which is more common? Are there any differences between them? Thanks!
There is a slight difference. The first one implies that the people who live in Asia eat rice, the second one could mean that eating rice is something that anyone visiting Asia or living in Asia does.
Personally, during a conversation I would say B.