One or two drinks won't do much harm, and may even have some health benefits such as increased HDL (good) cholesterol, but too much alcohol may have a significant negative impact on your health and negate much of your workout benefits. Alcohol is far more harmful than most people think, and it's very important to understand how it affects you. So, if you're serious about your weight, body fat percentage, health, fitness, and athletic performance, and want the maximum possible benefit from your fitness program, you should drink alcoholic beverages in moderation or not at all.
Not all is the better choice. Moderation is often defined as one drink for women, two for men. That doesn't mean you have a license to have 14 drinks per week (or have your week's worth in 1 night) men! One night out a week of binge drinking can nullify all those hours of sweat in the gym.
The most noticeable (and likely undesirable for many) result of drinking too much alcohol is weight gain. Why does alcohol cause us to gain weight? There are two reasons, and they work together to create that beer belly.
Alcohol is high in calories. Alcohol has the second highest calorie density of all food types. At seven calories per gram, it is the second most calorie dense "nutrient" (fat is number one, at nine calories per gram). Therefore, alcohol contributes a large number of calories to your total daily intake, above and beyond the food you consume. Because alcohol is metabolized by the liver, it is not converted directly into body fat, but this doesn't mean that drinking alcohol won't make you fat. Drinks made with soft drinks or juice add even more calories to the total, and even those of who watch what eat and count calories are often unaware of how many extra calories we are drinking.
Alcohol suppresses the body's ability to burn body fat. The body has no storage capacity for alcohol like it does for carbohydrates and fats. Since alcohol must be detoxified as quickly as possible, its oxidation takes priority over that of other macronutrients. In other words, while the liver is busy metabolizing alcohol, the utilization of fats, carbohydrates, and protein has to be temporarily suppressed. The burning of fat is suppressed the most, because it's at the bottom of the oxidative hierarchy.
Lyle McDonald, author of "The Ketogenic Diet" says, "The consumption of alcohol will almost completely impair the body's use of fat for fuel."
When alcohol is in your system, your body will simply convert more of the food you normally eat into body fat. Regardless of whether the calories come from food or drinks, if you consume more calories than your body needs, the excess will be stored as fat. Since most people usually consume their alcohol in addition to food instead of as a substitute for it, the accumulation of body fat is usually the result. You may have heard that its not the beer that makes you fat, but the beer nuts, and that is to some degree true, but they are actually ganging up on you to make you fat.
If you are a man and want your muscles to show, i.e. looked "ripped", your body fat percentage should be ten percent or less, and that will be very hard to achieve if you drink alcohol.
So, if you are working out and actually want to see your muscles, remember a six-pack (of beer) will ruin your six-pack (abs).