Great question but knowing that the majority of your trick o' treaters will be kids (and some silly young teenagers), keep in mind that they're enjoying childhood..eg. eating candy, not brushing their teeth, not worrying about caloric intake (and they shouldn't unless they're overweight).
My vote is for the - "status quo" nudging towards the diabetus. I say let them enjoy their youth and grab ahold of the inevitable stroke/dementia thing.
Or hey, maybe I'm way off and your neighborhood is full of veggie hipsters handing out Kale lolipops and sheets of seaweed and they actually enjoy that sort of thing...I guess someone has to be the pioneer here.
The pro of taking that approach would be if you hand out healthy candy and they hate it, they'll avoid your house next year and will be less of a financial burden to supply the streets with healthy veggie candy.