My limited knowledge of cappuccino is that it has frothed milk. Milk has quite a bit of lactose or milk sugar. They may also add sugar.

The cappuccino that our friends made and that we will make used no added sugar and heavy cream with a little water added for the frothed milk. So it is high in fat but low in sugar. As far as calories, the fat in the heavy cream will definitely have calories.

In my situation calories from fat I don't care about. It is the sugar that causes me blood glucose problems. Starches are what creates glucose for the most part.