What is the "nutritional calorie" count of beer? Beer has a fairly high calorie count - roughly between 150 and 300kcal per serving of 0.5l depending on kind. A significant percent of that is alcohol though, which is fully metabolized without any reserves whatsoever being retained - empty calories without actual nutritional contribution to organism.

I wonder what is the actual typical contribution of beer to human body energy reserves - energy from sugars, fats, proteins? How should I count beer in my diet?
It really comes down to the specific beer you are drinking. 

In addition to trace elements, and vitamins, the main dietary contribution of beer is from carbohydrates, proteins and alcohol.

Protein and Carbohydrates provide 4 kcal/g energy, while alcohol provides 7 kcal/g. 

With dietary planing, you need to look at the specific foods you plan to consume, and no different with beer and diet - here you'll need to look at specific beers to determine nutritional and energy value.