I posted this in the general gym rats thread but this is a good slide illustrating the beneifts (in terms of getting to eat more) of being a mover v.s. being a potato. This isn't even 'cardio', just not sitting down all day:
Over a day or week this can really, really add up - pulling some random numbers out of thin air, it's going to be a lot easier psychologically, give you more opportunity to eat both bigger meals and/or more varied foods and help your adherence if you're dieting on 2000 calories (not a potato) v.s. 1600 (potato) to create the same 500+ cal deficit. The trick is it has to be a lifestyle thing I've found though - you bike short distances rather than take the car, take the stairs rather than the lift and spend some of your lunch getting some fresh air because you want to, not because you feel like you have to.