How many calories are in alcohol?

The primary energy-bearing constituents of beer are alcohol and carbohydrates; beer has no fat and very little protein content. Light beers and low-alcohol beers carry less food energy than other beers . Even heavier beers carry less energy per glass than sugared cola drinks, and one study has shown that non-drinkers adding a single serving of alcohol to their diet daily does not contribute to weight gain. Other studies have also found alcohol consumption to be unassociated with weight gain, for reasons not yet understood. However, some beer drinkers consume high-calorie junk food—such as potato chips—alongside beer, while others simply drink inordinate amounts of beer. For instance, a 40 U.S. fluid ounce (1.2 liter) bottle of MGD (Miller Genuine Draft), which might be consumed as a single serving by a heavy drinker, contains about 485 calories (2,030 kilojoules).