Where do calories in beer come from?

TroubleShooting

Walter Scott • Reisterstown, Maryland asks,

One recent afternoon, over a few of our favorite beverages, a friend and I got into a good-natured argument. My friend is a diabetic (and a beer lover) so calorie and nutrition information is very important to him. We were debating just where the calories in beer come from. My friend’s opinion is that the alcohol provides the calories, based on the fact that a beer and a shot of liquor are considered equivalent. Having recently read the article on creating low calorie beers using “Beano,” (April, 2001) I hypothesized that the majority of the calories in beer must come from unfermented carbohydrates. Please educate us.