What is a small beer?  From reading around, it seems like medieval beer had a higher calorie content and people would drank a minimum a litre of day (1000-1200 calories).  Amusingly, unless you were a farmer or a soldier, there was an epidemic of obesity during the Medieval Ages and this was often compounded when people considered obesity to be an indication of wealth.

Should always be cautious about the "ye old days" (golden age) and "ye days of dirt" (nightmare) rhetoric on the Medieval Ages.