I'm on week 3 now of Vaping without a smoke.
I've been constantly hungry as well. I just kind of figured this was my appetite returning from all those nasty chemicals in cigarettes suppressing it.
For me, this is a great thing, since while I was smoking I would often times only eat once a day or sometimes go without a meal at all in favor of just lighting up.
It's starting to normalize a bit now. But, I'm still definitely more inclined to eat an actual meal now. It's awesome.
As a side effect of my increased appetite and ever returning lung capacity I've decided to actually start exercising to keep potential weight off and help my body return to a more favorable health.