Well, as I'm a diabetic my blood sugar increased because I was eating more, and then I had to take more insulin to combat that - and insulin is fattening, so it's just one vicious circle
I gave up for 3 years then started again because I THOUGHT I'd cracked it, now I've given up for 7 years and coould stil smoke one after a beer but don't because I remember living my life to 20 mins at a time till I could have a cig and that was far worse than a couple of months disruption