Hi Corley - welcome to ECF!
All of the above posts are pretty spot on - you're replacing the cigarettes with an alternative, less harmful method of nicotine consumption, so your metabolism likely won't slow down, and because you'll still have the physical action of bringing the PV to your lips, inhaling/exhaling, you probably won't find yourself reaching to snacks (at least not any more than you used to!

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As previously mentioned, drink lots of water (will keep you from feeling hungry - and very often people think they are hungry when they are really thirsty, also, vaping can be dehydrating, so drink 8 glasses, and then drink some more!), and if you find yourself craving sweets, try vaping a sweet flavor! ECBlendflavors has a fantastic Thin Mint that really does taste like a girlscout cookie (let it steep for about a week to give the flavors a chance to meld), deejstuff has amazing sweet flavors, and VapeDudes has a great s'mores vape. Buy small samples in the beginning to figure out which flavors you like (taste is really subjective, especially in vaping!), and when you hit on the flavors that satisfy you, order bigger bottles BEFORE you think you need to - running out is not a good thing!
This is a great place for you to find information, ask questions and get support - everyone is very friendly & willing to help!
happy vaping,
Cheeky