Whisky Weight: Can Drinking Whisky Make You Fat?

What a time to be alive when ‘low-carb’ potatoes are something you can actually buy – I’m not kidding. Carbs and calories are being discussed more than ever but do you know how your drinking is affecting your waistline? Here are some quick tips to help keep your calories from alcohol intake in check.

Know your units

In dietary terms, 1 Cal (big C) is actually 1 kcal or 1 kilocalorie. This is commonly referred to as a food calorie and is approximately the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius at one atmosphere of pressure.

From now on, when I refer to Calories (Cal), I am referring to kilocalories.

In the metric system, 1Cal equals approximately 4.2kJ or 4.2 kilojoules.

Alcohol by volume or ABV is expressed as a percentage (%) and is a measure of how much alcohol is contained in a given volume of an alcoholic beverage.

When referring to alcohol proof, US 100-Proof is the equivalent of 50%ABV whereas UK 100-Proof is the equivalent of 57.15%ABV. Whisky can be any ABV from 40% to as high as 70% (rarely higher). Typical whisky ABV is 40%, 43%, 46% or >50% for cask strength.

The Metric unit of measurement for the volume of a liquid is ml or millilitre. Whisky bottles are typically either 500ml, 700ml, 750ml or 1,000ml (1 litre) if bought at travel retail. A standard alcoholic shot volume is 30ml.

The Metric unit of measurement for the mass is g or gram; In Australia, a standard drink refers to 10g of alcohol (a US and UK standard drink are 14g and 8g respectively). A single 30ml measure of a 40%ABV whisky equals 1 Australian standard drink.

How do I calculate the number of Calories in my whisky?

1ml of alcohol weighs approximately 0.787g (0.787 is the specific gravity of ethyl alcohol at 25˚C) and 1g of alcohol contains approximately 7Cal. 

First, work out the amount of alcohol in grams (g):

   (ABV% x 0.787 x volume in ml)/100 = Alcohol in grams (g)

Therefore, the amount of alcohol in a single 30ml measure of a 40%ABV whisky would be:

   (40 x 0.787 x 30)/100 = 

= 944.4/100

= 9.444g

Then, multiply this figure by 7 to determine the number of Calories (Cal):

   9.444 x 7

= 66.1Cal or 278kJ

Likewise, the Calories in a single 30ml measure of a 60%ABV whisky would be calculated by:

   (60 x 0.787 x 30)/100

= 1,416.6/100

= 14.166g

Then, multiply this figure by 7 to determine the number of Calories (Cal):

   14.166 x 7

= 99.2Cal or 417kJ

If only it was that simple

What you have just calculated above is the calories of alcohol in your whisky. What this doesn’t take into account is any additional energy from residual sugars, mixers or the physiological effects of alcohol on the way your body processes energy. Let’s look at each in turn.

Residual sugars

Whisky, like beer, is produced by fermenting sugars from grains. Grains such as malt are used because they contain concentrated stores of energy in the form of starches that can be easily converted to sugars. The majority of sugars are consumed by yeast during fermentation but depending on fermentation methods and added ingredients, the residual sugars within the finished beer or whisky wash will vary. Most of the residual sugars in whisky are lost during distillation which means whisky contains very little energy from sugars; but it does have some, just a negligible amount when calculating Calories.

Mixers

If you drink your whisky with a mixer other than water, you are most likely adding plenty of Calories from sugar (unless the mixer is artificially sweetened). Refer to the mixer packaging for details but for example, 100ml of Coca-Cola contains 76Cal. But beware, the sugar content of your favourite mixers may vary depending on country of origin.

The effects of alcohol on your metabolism

When it comes to whisky and weight gain, the following is the kicker. Most people don’t consume huge amounts of whisky in a single sitting but even if you drank half a bottle (350ml) of 40%ABV whisky, you are only consuming 771.5Cal (3,239.5kJ) from alcohol. But, half a bottle of whisky is a significant amount of alcohol, just over 11 Australian standard drinks.

On average, it takes your body one hour to process one standard drink or 10g of alcohol.

Why is this important? Your body will always metabolise alcohol before it metabolises anything else. Why? Because the primary product of alcohol metabolism is acetaldehyde, a toxin, which must be processed by your body before more alcohol can be metabolised in order to avoid poisoning. Your body makes this process a priority, essentially halting the metabolism of any other energy source until it is complete. That means that any Calories consumed other than Calories from alcohol, will be converted to fat until all the alcohol is out of your system. So, anything you eat in the 11 hours after consuming half a bottle of whisky, will be converted to fat stores rather than metabolised by your body. Beware, this is the trap that most of us fall into when combining alcoholic beverages and food.

The bottom line

In most cases it isn’t the whisky making you fat, it is whatever you eat or drink with it, while alcohol remains in your system. So, rethink that drunken late-night kebab or just don’t drink half a bottle of alcohol in one sitting. In fact, if you are concerned about your health, probably do both.