I had a coffee half milk half water with one spoonful of xylitol. My blood sugar went up from 6.2 to 8.4. Puzzled as I hadn't eaten any breakfast. X
Xylitol is a sugar alcohol. I found this description:
Possessing approximately 33% fewer calories, xylitol is a lower-calorie alternative to table sugar. Absorbed more slowly than sugar, it does not contribute to high blood sugar levels or the resulting hyperglycemia caused by insufficient insulin response. This characteristic has also proven beneficial for people suffering from metabolic syndrome, a common disorder that includes insulin resistance, hypertension, hypercholesterolemia, and an increased risk for blood clots
So it should not raise the bgl significantly. It is more likely the lactose in the milk that has done that. People doing a low carb diet often use bulllet proof coffee, where the milk is substituted by whole cream or coconut oil to reduce carb input.
EDIT to add: Xylitol is a common sweetner used in chewing gum, and is extremely toxic to animals, especially dogs. Safe for humans.