My “Hobby” pays for itself, (plus some) I figure. Mostly because I don’t need or want high end bikes, and also because I save money by commuting by bike. For me that’s a saving of about $500 a year on gas alone. That doesn’t even including the savings on other wear and tear and maintenance items for the motor vehicle.
And no, I don't eat more when I ride, I eat just as much even when I don't ride. If you want to add "extra food" to your expenses for riding, then don't forget to subtract for lower health care costs, especially in the long term.
Another part of my bike "hobby" supplies me with money by doing bike repair and rebuilding for others, which I enjoy very much. Many a trash pickup or bike that someone has given to me has been turned into cash over the years. Then again, I’ve also given away several nice bikes to people in need.