Alcohol is high in calories and provides zero nutritional benefit. This means that a 400-calorie bottle of beer accounts for 1/5 of your daily calorie requirements, but does not give a single gram of protein or fibre. This is why drinking alcohol on a daily basis will make it much more difficult to achieve your bodybuilding goals. If you drink one glass of beer a day for a year, you will gain around 7kg, even if doing regular cardio.
The only alcoholic drink that provides any healthy substance is red wine, as it contains anti-oxidants. However, there are much more calorie-efficient ways of bringing anti-oxidants into your diet. The main benefit of anti-oxidants is to people with high blood pressure and other heart-related conditions, which are not likely to affect bodybuilders in their prime. The fact that red wine provides anti-oxidants is usually used as an excuse to drink it.
Alcohol is also severely dehydrating, which is highly detrimental to any exercise regiment. Additionally, it also prevents the body from absorbing certain vitamins, which impedes your ability to add muscle mass.
Excessive drinking is especially damaging to any workout routine. If you drink so much that you have a headache the following morning, or so that you can’t remember the previous night, you will set yourself back by up to 7 days, due to the lack of sleep and dehydration. This means that if you drink heavily once a week, you will never work out at peak performance. If you can’t achieve peak performance, you are not straining your muscles hard enough to add muscle at any significant rate.
If you drink regularly, you are placing a considerable strain on your liver, as it needs to filter the toxins from the alcohol in order to prevent it from entering the blood stream. Due to this it is extremely important that you do not mix nutritional supplements (especially Creatine) with alcohol, as they both burden the filtration mechanisms of the liver. In extreme cases, over-use of alcohol and/or Creatine can result in liver failure and death, as the liver is not able to filter fast enough to prevent the poison from entering your blood.