Vodka is the least fattening alcoholic drink as it contains no sugars or carbohydrates - only the calories from the ethanol produced in the fermentation process.
It is also the cleanest type of alcohol as it is filtered repeatedly and so very little impurities remain - it is these that often affect how bad your hangover is
Calories: 72 per 35ml shot
Chance of a terrible hangover: 3/10