Hi Kegstore,
A calorie is a unit that represents the energy provided by food. Carbohydrate, protein, fat and alcohol are the food types that provide calories in the diet. Carbohydrate and protein have 4 calories per gram, fat has 9 calories per gram, and alcohol has 7 calories per gram. So, for a non-diabetic, the amount of calories consumed is important, regardless of which food source they come from. Not only does alcohol contain calories, but it also slows down the rate at which the metabolism burns energy, so can result in increased fat storage.
As far as a diabetic is concerned, alcohol contains no carbs and so cannot increase blood sugar. In addition it stops the liver from creating unwanted glucose, so can actually lower blood sugar levels.