well, there's two things

one, is it contains sugar, about maybe equal to 1/5th of a teaspoon in every cup, maybe a little more, it is caramels though, so it's something between sugar and starch

the other thing is that paraxanthine, the main active metabolic byproduct of caffeine metabolism by the liver actually stimulates the conversion of fats to sugar, so it definitely does raise blood sugar levels, just not so much as actual sugars, but not zero, as you can see considering the two points, probably a cup of coffee is equal in blood sugar rise to 2tsp of sugar, and then you put another tsp on top... 

 "then you put another" 

No I don't put sugar in anything. wtf 

 most people do though, i see them all the time... here in madeira it is standard to put about half a teaspoon of sugar into an espresso shot, known as a "bica", to the point where it's so common they just give you the sugar with an espresso shot, and a spoon to mix it in