Here’s the alcohol and calorie content of 200 Popular Beers. This is pretty dated (1993!) but will give you a picture of how much of your diet you can obliterate by having a pint or three.
A pint of beer is 19 U.S. fl. oz., allowing 1 oz. for the head. That’s 562 mL. If Guinness Extra Stout is 43 cal per 100mL, then a pint is roughly 242 calories.
Now you know.