Exercise it & feed it a good meal. Same as people.
The backfire, of course, is that the dog will get fitter which means more exercise, etc. I used to take my kelpie to a big park and have him chase me around on a bicycle. [But his little paws kept slipping off the pedals.] Naturally, this assumes the dog is ok in open spaces off a leash. Won't attack other dogs or try to eat/pee on people's babies, comes when called, doesn't range too far, etc.
I don't think it's bad for them but I've been told that dogs aren't built for distance running. On the other hand, every sprinting frisbee fetcher ever has fucked up his ACL with too quick direction changes. What I'm sure of is that dogs aren't designed to wait around all day in a back yard with nothing going on. If he has to stay home while you go to work then find a good way to wear that fucker out morning & night for a couple weeks as an experiment.
