I have what I would consider to be "Interests" but no real hobbies. Maybe I'm drawing too distinct a line between the two.
For example, I have a gym membership and work out regularly. Yet, I consider that more of an interest than a hobby. But maybe that is a hobby?
I guess I think of a hobby as more of something that one spends hours on and is meticulous about. I'm not terribly meticulous about fitness. I don't micro-manage my diet, for example, weigh foods and count protein grams, etc. To me, that's what would put fitness into the category of a hobby.