Some people think that because most alcohols have low or zero carbs, that you can drink unlimited amounts of them on a diet and not gain weight. That is completely untrue!
First, let's review some basic biology. Your human body burns fuel for energy. If it doesn't get that fuel from what you eat, it turns to your reserves - your fat cells. So the aim of a diet, whatever its type, is to supply your body with less fuel than it needs, so that it has to burn those fat cells for its daily living. That's how your fat cells "go away" and you lose weight.
There are only four types of fuel that your body knows how to burn. These are:
* Protein - i.e. meats, eggs, etc.
* Fats - i.e. veggie oils, meat fats
* Carbs - i.e. cane sugar, natural plant sugars, starches
* Alcohol - i.e. vodka, rum, whiskey, bourbon
The point of a low carb diet is to reduce the nasty, unhealthy carbs that most modern day people eat - the pounds of sugar introduced into peanut butter, ketchup, bread, soda, and every other unnecessary location. Why do we need excess sugar added to every single ingredient of a peanut butter sandwich? Are our sweet toothes so oversaturated that even sweet grapes need added sugar to be jelly?
So the aim is to eat lower sugar items - i.e. broccoli, cauliflower, whole wheat bread - in the "carb family" of foods. Then you add in healthy amounts of the rest of the food groups - i.e. fresh fish, chicken, fish oils, grapeseed oil, etc. Your body needs protein, it needs oils, it needs good carbs. It just doesn't need all that excess sugar.
This is a key concept. Low carb *never* says to eat outrageous amounts of anything at long as it's low in carb. Take for example protein. Protein is an energy source. If you created a diet of 100 pounds of ground beef every day, you would become sick and fat quickly. You wouldn't be getting in vitamins, or fiber, and you'd be getting way too much energy from that protein. You wouldn't be losing weight, you'd be gaining it, while your body came down with scurvy and other nasty diseases. A diet needs to be in moderation with adequate amounts of each group - but not overloaded in an area, even if it's a low carb area.
Which brings us to alcohol. Yes, alcohol is zero carb. But it still supplies energy. Not only that, but the way metabolism works, alcohol (because it's in essence a poison) is metabolised first, to get it out of your system. So if you drank in X amount of alcohol and then ate 20g carbs at the same time, your body would first work on burning up that alcohol. Only after that would it start working on the carbs. Let's say it got all the energy it needed for your daily tasks from that alcohol. The carbs are now "excess" and will be stored away as fat!
When low carb diets tell you to "eat 20g a day", that is with the assumption that those 20g will be your day's fuel for your body, and since your body needs more than 20g to live, the rest of what your body needs will be drawn from your fat cells. But if you drink 10 shots of whiskey a day, your body will get MORE than enough energy from that whiskey, and you'll be gaining weight.
So for the first two weeks, you should go sans alcohol, so that your body gets used to burning your built-in fat for fuel, NOT alcohols or other items. Even as you start to ramp up, always drink in moderation. Alcohol isn't a carb, but it is an energy source. Small amounts won't have an impact on your weight loss - but larger amounts will definitely interfere with your body's desire to burn fat cells because it needs more energy.