To look good in media, most men jog. He has chosen not and that is okay.
I don't think so. A lot of people, in fact I'd say the majority in the country don't do sufficient exercise (due to work, laziness, time etc etc) and they don't end up as bloated as Christie. At worst you'll become slightly overweight and develop a bit of a stomach, in the same bracket as a Jon Tester or a Mark Pryor.
Christie is morbidly obese. You can't simply attribute that to not jogging enough. The man simply eats way too much junk food, more than the average man and has no self control over his eating habits. It's the only way you can end up that humongous.
Anyway unless he suddenly gets a health scare in the next three years I don't think it'll become an issue in his inevitable campaign for president.