BEER CLINIC :: Part 1 — Does Beer Make You Fat?

by Dr. Carol Westbrook on June 21, 2011

I’ve heard it time and time again — Beer makes you fat. Beer gives you a beer belly. Don’t drink it. We’ve already established that beer is good for you (see, YourBeerNetwork, 1/19/2011, The Beer Clinic: The Health Effects of Beer) but does it really make you fat?

It was time to put my biochemistry background to work and get the real answer. The most logical place to start was simple dietary information in a typical beer. Just read the label, right? Wrong!

Do you ever wonder why there is no nutritional information on a beer label? Every other food and beverage you consume contains a label that tells you the exact number of carbohydrates, protein and fat, sodium, vitamins, additives, allergens. Even water bottles are labeled with the calorie, protein, fat and carbs (usually 0)!! Every beverage, that is, except beer and wine. Why? Because beer is not a food, which is regulated by the FDA, and which requires nutritional labeling. Beer is regulated by the Department of Alcohol, Tobacco and Firearms, ATF. In fact, the alcohol content is not on the label unless it is an import (so far as I can tell, anyway).

How frustrating to try to figure out whether or not your diet allows you to have that second pint of beer! You can get information on the calorie count of your beer, but you will have to go online to the brewery’s web site, or check an online source for dieting and see if your beer is listed; my favorite is Calorie King.

But wait — that’s not the end of the story. The posted calories are not accurate because they include calories from alcohol—and alcohol calories don’t count the same way as food calories.

So, not all calories are created equal! When you consume fat, sugar, carbohydrate or protein, the food is metabolized to completion (CO2 and H2O), or else it is stored as fat to be metabolized later. The calorie content of a food can be measured pretty accurately by burning it to completion in a small chamber, and measuring the heat released. But the calories measured for alcohol do not reflect how it is metabolized. That’s because the alcohol that you consume is not burned to completion, it is only partially metabolized. These incomplete metabolic products are not stored as fat but are lost into the urine and exhaled in your breath as acetaldehyde or acetic acid. It has been estimated that only about 16% – 20% of the calorie potential in alcohol is actually available to the body.

One ounce of pure alcohol has a theoretical content of 198 calories, but the body only sees about 31 of those calories. So if you want to know how many “true” calories are in your beer you will first need to look up the posted calorie content and the % alcohol, calculate how much alcohol is in the volume of beer you are drinking, then apply a correction factor

This is my equation, using a very conservative 20% metabolism rate for beer:

True calories = (published calorie content) – (# ounces of alcohol x 160) = calories in your beer.

Let’s look at two examples, using data from Calorie King.
(1) 12 ounces of Guinness, (4% ABV), contains 0.48 oz alcohol and 126 calories. Corrected calories: 126 – (0.48 x 160) = 126-76 = 50 calories
(2) 12 ounces of Sam Adams Boston Lager (5% ABV), contains 0.6 ounces of alcohol and 180 calories. Corrected calories: 180 – (0.6 x 160) = 180 – 96 = 94 calories.

That’s not too bad, is it? Much better than a sweetened martini, a piña colada, or even a Coke.
Good luck trying to solve the equation after a couple of pints. Forget it. Just go ahead and have the next one.

NEXT: Part 2 — Why does beer make me fat if the calories are so low?

{ 4 comments… read them below or add one }

Art Cunningham June 7, 2011 at 2:40 pm

Very interesting, Carol! According to your calculations above, it sounds like about 2/3 to 3/4 of the calories from a bottle of beer come from alcohol, and if the body only metabolizes 20% of that alcohol, the calorie count is drastically reduced. That’s good to know! I’m anxiously waiting for Part 2, where I assume a sedentary lifestyle and the actual number of beers you consume in an hour (significantly impacting how your body metabolizes the calories) has something to do with the equation. Keep up the great work!


Dr. Carol Westbrook June 7, 2011 at 5:13 pm

Thanks for the comment, Art. There’s more to the story. Future articles will be about alcohol and “your brain on beer.”


Lori Sue Howell March 13, 2013 at 7:35 pm

Ok. I gain a LOT of weight when I drink beer. I stopped drinking for the heck of it and guss what? My family thought I had cancer I got SOOOOOO skiny. So I drink 2 22oz bottles EVERYDAY just to look like I won’t blow away in a wind storm. Why is it that beer is aal I can gain weight on?? I eat bacon lots of breads and chips too. So why??????


Jeff May 23, 2013 at 2:51 pm

If that is true about the amount of calories is actually low, most people get hungry and eat a bunch of food while or after drinking which makes one fat because I read that alcohol metabolism takes precedent over normal food so that all goes to pure fat until your liver recovers.


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