Most people hate to think about how many calories they consume on a typical Saturday night of drinking. Unfortunately, the truth is that most of us are consuming at least 400 extra calories when drinking. But this daunting reality shouldn't be a fear of yours any longer - we've made a list of some of the least caloric cocktails around, and most of them are under 100 calories - perfect for those odd occasions when you’re out with the girls or having a party for one at home.