I may not have read closely enough but, if I recall, you said the people were your students.  If they are minors, its not a good idea to instruct them on anything health related.  That is a parental job, not a teacher's.  That said, I'm an x-smoker and a diabetic.  I have recommended vaping to my non-smoker diabetic friends as its the only means of tasting foods they can't normally eat.  When I first started vaping, I enjoyed cheese cake zero nic juice for instance and vaped away as the rest of the family ate their cheese cake during the holiday season.  I did, initially, loose a bit of weight but after over a year vaping, that has leveled off but I don't vape for that purpose.  If I did, weight loss would probably continue.  When I recommend vaping, I instruct not to inhale.  Inhaling is not necessary for anyone but especially not if vaping is being used for dietary purposes.  Personally, I think vaping is much safer than consuming something that tastes like food but has no food whatever in it... just an arm-long list of chemicals most people can't even pronounce.  Tasting vapor, IMHO, is much safer than swallowing a bunch of chemicals.  For instance, before vaping, I used to eat Walden's chocolate sauce in which the caloric, fat and carbs counts were all zero.  I would much rather vape chocolate than swallow that stuff ever again.  And those chocolate diet products that have at least some food value contains sweeteners that... well, the bathroom gets a workout.  That can't be good for anyone.  Anyway, my two loooong cents.... don't recommend vaping to minors and if you're talking to an adult non-smoker instruct them on how to vape without inhaling and NEVER give them juice containing nicotine.