I think popcorn might be OK in some forms but there's loads of recipes for low carb snacks. Dark chocolate (above 80% cocoa) is OK. I can recommend joining the Low Carb programme (if you can get it for £20 or so for a year instead of the usual £70). I've made a Twix-type snack using ground almonds, cream and dark chocolate from there, which is pretty good. Also Diabetes.co.uk has loads of recipes.
cheers PB - am scouring the diabetes.co.uk website as we speak.
A Twix-type snack sounds intriguing. We attempted a chocolate avocado pudding using 80% dark chocolate yesterday without much success!