While liquor doesn't have the carbs that beer does, the higher alcohol content still packs on the calories. Liquors like Jack Daniels, Jose Cuervo and Captain Morgan may fill you up less, but the calories are still there.
In a 1-oz. serving of Jack Daniels whiskey, which equates to a little less than a full shot at a respectable bar, contains about 69 calories. While that may not seem like a lot, after a couple of these bad boys mixed with cola, you've racked up quite a few calories.
A 1-oz. serving of Cuervo fairs a little better than Jack in regards to calories with a subtle 64. However, what you mix with tequila is even worse than whiskey. Margarita mix is almost entirely sugar.
Captain Morgan's Original spiced rum is the lowest of the three in terms of calories. One oz. of Captain has only 60 calories in it. But just like the other two, what you mix with rum can rack up quite a calorie bill, especially when you begin to get into those fruity tropical drinks that are chock full of sugar.