At his current weight, yes. He's way above the "living the good life" fat (20-30 pounds). Although the White House doctor was out of line for "giving him advice", he will not be a serious candidate until he loses probably 75-100 pounds. He can still be heavy and a serious candidate, but not at his current weight. He seems like a good politician (i.e. pander to whoever will listen to get his agenda through). I'm mixed on the guy with regard to his principles.
If you're voting for a guy over his weight, then there might be a problem. You need to listen to his actions, not the jiggle or gurgle his stomach might make.
You say that, and I suspect you are sincere and you make good points. However, sociological studies confirm year after year that tall people, fit people and attractive people are perceived as "better" (more intelligent, more competent, more interesting, more humorous, etc.). Some reconciliation with the pettiness of USA society is necessary for serious contention in the ultimate game of control.
I'm not denying the importance of image. It's important in whatever you do. But that's more for trying to introduce someone. People know who Chris Christie is. Liberals know him as the person who talked ill of Republicans during Superstorm Sandy. The GOP know him as a tireless campagainer who cares more about issues then party. Introducing to the uninformed might be the actual problem.