Be honest, as the interviewer might have read it too. There's no shame in admitting to lightweight reading material if that's what you like - put it in context, why you read it, and give a positive result, whatever it is. Be able to give an intelligent reaction to what you've read. Don't be too clever or try to impress as nobody likes a smart arse.

 This is a good question to know the answer to before you go into the interview. Make a list of books, movies, blogs, newspapers, magazines, etc. - especially if they are related to your field of work or your career of choice. You want to present yourself as the ideal candidate, whose personal interests and are in line with that of the company or organization you want to work for. You need to present yourself as if you belong or that you will 'fit in well' with the company culture. If you do this before the interview, you will have no problem replying confidently with an answer that you fill comfortable giving to the interviewer.