Just so you know, I was sick for like 2 weeks (severe stomach pain, diarrhea, nausea, TMI in know sorry!) at the beginning of my IP journey, and Doctor, and Coach were thinking it was the sweetener (motsly splenda).. I've now stopped using it except when necessary, and I'm feeling much better.
I think we need to be careful about it, even if it's not causing a sugar spike, because it's an artificial thing anyway !
I also agree with your doc and with erin, if you're loosing fine, and your body is not reacting badly to it, then it's ok with you using it