Or new lifestyle? Quitting the fags inevitably means stuffing faces and looking through a few topics, it is an issue. Many of us have smoked instead of making breakfast or grabbing a bite to eat, so not smoking could leave us finally wanting to fill the void a fag has left and finally recognise hunger.
If you don't have a weight problem yet, chances are things will settle down and you will be able to get back to being comfortable. If you are already overweight or have been there, you may be worried you are going to undo all your hard work and gain all the weight.
I think food/drink logging works, you don't have to write everything down. Just take a pic of anything you are about to put into your mouth. Don't tell me you are too busy, you are not too busy to stuff your face and if smoking you would have 2 min fag break
I think the obvious will be drink more fluids, not juice or processed rubbish. Try giving up other stimulants like coffee as caffeine triggers insulin (fat monster) and switch to decaf. If you take sugar already but are drinking more, try cutting it down/out as that will cause a gain. If you are going to snack, try recognise the reason you are doing it. Chew gum, but don't pig out on sugary food, it won't help the addiction and more inclined to swap.