Periodically walking outside, especially in a large office complex, to stand in the cold and smoke is also a good way to lose weight.
and don’t take the elevator :)
As is pushing back from the desk, getting up from the chair, stretching and doing a toe-touch or two, walking to the door, going outside, doing a few deep-breathing moves, walking down the street to the 7-11, buying some beer and returning home.
Exercise...its a good thing.