Good question, I’ve read many times on T-Nation that alcohol should not be consumed as it hinders one’s progress, and I have accepted it blindly.
I went to PubMed, did a bit of digging.
A) I couldn’t find the full article, but the abstract is quite clear, in that Vingren et al. (1) did tests on rats showing that: “Chronic alcohol intake appeared to reduce the AR [Androgen Receptor] content of the type IIB fiber-predominant rectus femoris, and this reduction was not affected by RT [Resistance Training]. In the type I-predominant soleus, chronic alcohol intake alone had no effect but seemed to prevent RT-induced increases in AR content.” This is a significant finding since the soleus muscle is so large and powerful. The Androgen Receptor is involved in the proliferation of protein gene transcription. Less AR in a muscle simply means less protein being synthesized in that muscle.
B)Reed AH, McCarty HL, Evans GL, Turner RT, and Westerlind KC (2002) explored alcohol’s affects on bone mass. They guaged alcoholic rats that exercised, versus alcoholic rats taht did not exercise and found no difference in bone mass, but they did find a difference between the alcoholics and sobers - this was that the alcoholic rats had significantly reduced bone formation. So, alcoholism could be especially troublesome since resistance training athletes put extra stress (compared to non-athlete-people) on their bones: leading to fractures and breaks.
C) To avoid bias in me picking out studies, it should be noted that two other studies were quasi-inconclusive in that they affirmed the need for more research into the area of question (3) (4).
(1)Vingren JL, Koziris LP, Gordon SE, Kraemer WJ, Turner RT, & Westerlind KC (2005). Chronic alcohol intake, resistance training, and muscle androgen receptor content. Issue 37,11; 1842-8.
(2)Reed AH, McCarty HL, Evans GL, Turner RT, & Westerlind KC (2002). The effects of chronic alcohol consumption and exercise on the skeleton of adult male rats. Issue 26, 8; 1269-74.
(3)Burke LM, Collier GR, Broad EM, Davis PG, Martin DT, Sanigorski AJ, & Hargreaves M. Effect of alcohol intake on muscle glycogen storage after prolonged exercise (2003). 95, 3; 983-90.
(4) Chicco AJ, McCarty H, Reed AH, Story RR, Westerlind KC, Turner RT, Hayward R. Resistance exercise training attenuates alcohol-induced cardiac oxidative stress. Eur J Cardiovasc Prev Rehabil., 13, 1; 74-9.