Same here. I look for the things that others here look for. And I too prefer to avoid corn syrup but will still eat foods that contain it on occasion. Cane sugar and corn syrup don't give me diarrhea, but they do make my poo less formed. My digestive system seems to have the least issues with cane sugar the most among the lot, then corn syrup. I always look to make sure that cane sugar is listed in the ingredients when I'm craving something sweet. If corn syrup is listed, I'm more careful.
The worst artificial sweeteners for me are the ones that end in "itol." I avoid those like the plague.
I've never tried stevia, saccharin, or aspertame.
Figuring out how to reduce a flare or get into remission is a trial and error experience. Don't expect your GI to have all the answers. He was trained in making diagnoses, prescribing medications, and surgically removing the colon. He was not trained in alternative treatments. That's why they are called alternative treatments.
What works for me: Fecal transplantation, Probiotics, Anti-inflammatory foods, No HFCS, No crystalline fructose, No foods high in fructose, No artificial sweeteners, No pro-inflammatory foods when flaring, Vitamins, Lexapro (for stress).