Beer on a Low-Carb Diet

Why Beer Differs From Other Alcoholic Beverages

Glass of Beer At Bar
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There is a lot of confusion as to whether some beers—or any beer for that matter—are appropriate for a low-carb diet. Some people will tell you that the carbohydrates in beer are different from those in wine or whiskey and are far more glycemic. Others will tell you that alcohol stops your body from burning fat and will stifle your ability to lose weight.

So, what is the truth? Is beer is just another alcoholic beverage, or are there properties that make it entirely unsuitable for low-carb eaters?

Alcohol and Metabolism

There has long been a misconception that people gain weight from alcohol because it is transformed by the body into sugar. This is actually not true.

While there may be carbs in certain alcoholic beverages, which are converted to sugar (glucose), alcohol is treated by the body in an entirely different way.

When you drink an alcoholic beverage, your body will automatically identify the alcohol as a toxin. As the alcohol is absorbed in the small intestines, it will be delivered to the liver to be broken down and eliminated from the body. During this time, all other substances—including carbohydrates and fats— will be put on hold.

As a result, the carbohydrates in your body will not be converted to glucose for energy. Blood glucose levels will drop, and the fats meant to be metabolized by the liver will also remain untouched, further lowering glucose levels and even triggering weight gain.

As such, it isn't the sugar in alcohol that's necessarily the problem; it's the dampening effect alcohol has on metabolism.

With that being said, if an alcoholic beverage is high in carbs—as beer can often be—it can increase blood glucose levels and trigger an insulin response along with the other detrimental effects. This is where beer is different from wine, which is low in carbs, and hard liquor, which has none.

Beer and Carbohydrates

Not all beers are created equal. In fact, some are relatively low in carbohydrates and may be suitable for a moderate- or even low-carb diet. Others are entirely off-limits if you are strictly limiting your carb intake.

The carbs found in beer are the residual sugars left behind in the fermentation process. The carbohydrates in grain, the basis of beer, are far more complex than those in fruit, the basis of wine. This means that the yeasts used to ferment the carbohydrates have a far more difficult time converting grains to alcohol than it would with grapes.

By contrast, hard liquors are distilled, meaning that they boiled off to get the pure alcohol, leaving all residual carbs behind.

As a result, the average beer will have 13 grams of carb per serving versus four to five grams for wine and zero for whiskey, vodka, and other hard liquors.

Comparing Beers

The public's growing interest in lower-carb beers has led manufacturers to produce products that meet the low-carb standards but often at the expense of taste. As a general rule, the lower the carb count, the lesser the flavor. There are exceptions, of course, especially among small-batch producers who are starting venture into the low-carb market.

Broadly speaking, beers can be broken down into the following categories:

  • Ultra light beers are extremely low in carbs as well as calories. On average, you can expect to consume two to three grams of net carbs (the digestible carbs) per 12-ounce serving. Options include Miller Genuine Draft 64, Budweiser Select 55, Michelob Ultra, Molson Ultra, and Labatt Aspens Edge.
  • Light beers are a bit more flavorful than their ultra light counterparts and deliver between three and six grams of net carbs per 12-ounce serving. Popular brands include Miller Light, Busch Light, Coors Light, Corona Light, and Becks' Light.
  • Reduced-carb beers are not marketed as such but are fall below the threshold of 13 grams of net carbs per 12-ounce serving. Some, like Michelob Golden Draft, have as little as seven grams per serving, while others, like Carlberg, offer 10 grams per serving.

Beers to Avoid

In terms of knowing which beers to select and which to avoid, use the beer's color and characteristics as a guide. Generally speaking, the darker the beer is and the denser the head (foam), the more carbs it will have.

For example, honey, tan, and black lagers can set you back anything from 15 to 17 grams of net carbs per 12-ounce serving. Stouts and porters, which have fuller body and flavor, may have as many as 20 grams of net carbs per serving. Some craft beers can even be higher, wherein you gain flavor at the expense of 30-plus grams of net carbs per serving.

While beers are definitely not off the menu if you choose wisely, be sure to count them as part of your daily intake if you are on a strict low-carb diet. If in doubt, check the nutritional label or speak to the brewer. If all else fails, opt for a glass of wine or other low-carb beverages.

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Article Sources
  • American Society of Beer Chemists. Total Carbohydrate in Beer. J Am Soc Brewing Chemists. 2018:41(3):107-9. DOI: 10.1094/ASBCJ-41-0107.