title_body: Can one put on weight by drinking beer?
upvoted_answer: Beer can make you gain weight by three means, but you shall NOT pursue it !
  
  First is alcohol, which is a byproduct of the fermentation of starch by yeast. Starch is a carbohydrate, and it has it's own nutriting quality, including energy. Its energy is transferred to alcohol.
  
  If the energy it carries is not used by basal metabolism or physical activity, it'll be stored. It is why non pathological drinker get fat. But drinking regularly may drive you to pathological drinking, even when you never get drunk nor make any excess.
  
  Second is cereal malt (beer component) and non fermented starch itself : first is an aliment (cattle) and second is a carbohydrate : they are particularly fit for storing when unused.
  
  Third is oestrogen. Hop, the flavouring and conservative plant used in beer production carries a phyto-oestrogen, which has the same effect on the human body as the feminine hormone. One of the effect of oestrogen is modifying the fat storage (many a women complain on her weight change under contraceptive pills), both for developing sexual character (women's are the sole primate with permanent breasts) and storing fat in case of starvation during pregnancy.
  You already guessed why messing with hormonal rates in your body is no option.
  
  I strongly recommend you to seek help in gaining weight from a trained medical staff, or at least from a specialized Stack Exchange site. A change in your feeding habits may be way more efficient and less hazardous.
  
  Basically, you must eat and brink more than your body burns, while making the right amount of physical exercise to gain muscles as well as body fat. Beer nutriment don't really matches the kind of food you shall seek with this objective.
  
  Sources: Wikipedia, French medical awareness websites, and my personal experience as a beer cellarman.