When it come to nutrition, alcohol is a subject that always comes up. Although alcohol in small amounts is debated as a healthy thing, alot of research has proven that the drawbacks to alcohol far out weigh any potential benefits. Alcohol has been shown with even one drink to disrupt sleep, which as we know sleep is the most important time for recovery. Alcohol has also been shown to negatively impact immune function, carbohydrate metabolism, liver inflamation, vitamin and mineral absorption, testosterone and hormone levels, as well as cognitive function and coordination. All of which especially when added together, have a huge impact on our fitness performance, training, recovery, and progress. Anyone wanting to compete in any sport at a high level should obstain from regular drinking. Here are a few articles going into more depth.

http://link.springer.com/article/10.2165/00007256-200535030-00005#

http://www.nature.com/ijo/journal/v32/n6s/full/ijo2008206a.html

http://onlinelibrary.wiley.com/doi/10.1111/j.1530-0277.1998.tb03671.x/abstract