It is my understanding that enzymes in our malted grains convert starches to sugars. We lauter the liquid from the solids collecting a sugar rich wort. Once boiled and cooled we pitch yeast which consume the sugars producing alcohol and CO2. My question: if every drop of wort including all the sugars are digested by the yeast, can there be very many carbs leftover?
The carbs in beer come from any residual (unfermented ) sugars. Unfortunately for us ethanol also has a lot of calories.
The thing is that not every drop of wort is digested by the yeast, otherwise every beer would finish at a gravity below 1.000. The remaining gravity points are primarily dextrins and/or unfermented sugars remaining after fermentation, and these are all carbs.
and dont forget, carbs are our friends 
Makes sense to me!
What makes all this counterintuitive is that the carbs, which are currently deemed to be evil, are mostly left by the whole grain malts, especially darker, highly kilned ones. We all know that whole grains are good for us. Meanwhile, the simple sugars, which are clearly bad for our health, leave behind no evil carbs. Another case of alcohol turning good things bad and bad things good.