It’s said that, generally speaking, a beer will have about 60% of the calories from alcohol and the remaining 40% from the residual carbohydrates. To put this into perspective, a beer like Sam Adams Boston Lager (4.9% alcohol) has about 175 calories per 12-ounce bottle.
https://www.homebrewersassociation.org/how-to-brew/how-many-calories-are-in-beer/
Where Do Beer Calories Come From? In beer, the main sources of calories come from carbohydrates and alcohol. Both carbs and alcohol are a derivative of malted grains used in beer making to provide the sugars that will mostly be broken down by yeast to form alcohol and CO2.
https://www.homebrewersassociation.org/how-to-brew/how-many-calories-are-in-beer/
While they are not good for your diet, they will do less damage than many of the beers listed further down. The beer nutrition facts are listed for a 12-ounce serving unless otherwise indicated. Michelob Ultra beer (4.2 ABV) contains 95 calories and 2.6 grams of carbohydrate and 0.6 grams of protein.
https://www.verywell.com/diet-friendly-beer-choices-3495641
Guinness contains roasted, malted barley (Irish), hops, yeast and water. According to Guinness, a pint (16 ounces) has 210 calories and 12 ounces of beer about 170 calories. They say that Guinness has some vitamins and minerals, but they don't publish any nutrient values. The alcohol content is closer to 3.2% beer.
http://www.dietitian.com/alcohol.html
The calories in alcoholic beverages come from alcohol, which contributes 7 calories per gram as opposed to 4 calories per gram for protein and carbohydrate and 9 calories per gram for fat. So if you take 7 calories per gram times approximately 14 grams of alcohol per jigger (1 1/2 ounces), this equals 98 calories.
http://www.dietitian.com/alcohol.html
The beer nutrition facts are listed for a 12-ounce serving unless otherwise indicated. 1  Michelob Ultra beer (4.2 ABV) contains 95 calories and 2.6 grams of carbohydrate and 0.6 grams of protein. 2  Busch Light beer (4.2 ABV) contains 95 calories and 11.2 grams of carbohydrate and 1.7 grams of protein.
https://www.verywell.com/diet-friendly-beer-choices-3495641
* The average light beer has just over 103 calories in a 12 oz bottle or can. These beers are typically lighter in color and are lower alcohol beers. The range of calories in light beers vary between 65 and 120 calories. The ABV of these beers range from 3.2% up to 5%. * The average microbrew or full strength craft beer has about 156 calories per 12 oz bottle. These beers tend to use a bit more grains than macro beers.
http://www.fermentedlychallenged.com/2008/08/truth-about-calories-and-beer.html
So assuming that the majority of calories in beer come from alcohol, to find the calorie count of a beer, you can simply multiply the amount of alcohol (in grams) in that beer by seven. The calculation is simple, precise, and wrong. *What we normally call calories are actually kilocalories, or 1,000 calories.
http://drinks.seriouseats.com/2013/10/cocktail-science-do-alcohol-calories-count-digesting-spirits.html
A 12 oz light beer may have 110 calories but that jumps to 149 calories in a pint. A 12oz craft beer has 180 calories but leaps to 243 calories in a pint. And let's not forget that beer also comes in 22oz bombers. I'll let you do the math on that size bottle.
http://www.fermentedlychallenged.com/2008/08/truth-about-calories-and-beer.html
Answer Wiki. Short answer: The calories in an alcoholic beverage come from the body's metabolism of the alcohol itself. Yes, our bodies can use alcohol as fuel, just they can use fat or sugar. Actually, they can use vinegar too, and pound for pound, the acetic acid in vinegar has almost as many calories as the ethanol in alcohol.
https://www.quora.com/Why-do-alcoholic-beverages-have-calories
where do calories from beer come from
About 60% calories of beer come from alcohol and the remaining 40% from the residual carbohydrates. In the beer there are about 60% of the calories from alcohol and the remaining 40% from the residual carbohydrates.