Your interviewer is curious about what your hobbies will say about you, but they are also interested in how you maintain a work-life balance. Additionally, they need to make sure you are a good fit for this position, and getting to know you better as a person may help answer those questions. When answering, be open and honest, and discuss activities that reflect your professionalism or how well-suited you are for the role. This should include hobbies, such as exercise, eating well, or stress management. Avoid discussing anything that may be loosely interpreted as a conflict of interest.