You have to be careful with sugar alcohols

but they're not all bad.

I keep Quest bars and cookies on hand in case I need to carry something non-perishable during travel or when I know I'll be running around all day. They use erythritol or allulose (the latter technically a "rare sugar" and not a sugar alcohol). I've found I don't experience gastro distress with those.

It's maltitol that's usually the killer. It's the one that's most commonly in sugar-free syrup and candy and it apparently has a higher glycemic index than regular sugar.