I enjoy alcohol. It is far and away the most popular mind-altering drug. It’s legal, readily available and popular with governments for raising taxes.
Unfortunately, it serves no useful purpose apart from altering your mind. Although it contains calories, the body does not use it directly as a source of energy.
Once absorbed by the gut, it is removed from the circulation as quickly as possible by the liver.
How the Liver treats Alcohol
The liver treats alcohol as a high-level poison and prioritises its metabolism: that is, it breaks it down into simpler molecules, including acetone briefly before disposing of it as fat.
The fat is stored in the liver and gives rise to Alcoholic Fatty Liver Disease. It is worth noting that the liver throws all its huge resources into the task. Just about everything else the liver is supposed to be doing will stop until the alcohol is gone.
A bottle of dry red wine contains roughly 600 calories. There is some residual sugar but most of that 600 is alcohol. There are 9 calories in 1 gram of fat so that results in about 66 grams of fat.
That’s not a huge amount of fat, but if you drank one bottle each night you would gain about 24 kilos a year!
How are the Calories Burned?
On the other hand, your body is continuously burning calories 24 hours a day. If, for the sake of argument, you use 1,920 calories a day that averages 80 calories an hour. If you were able to access the liver fat derived from the alcohol, you could burn it up in 600/80, say 8 hours. It could all be gone by the morning, provided you don’t eat any other calories.
In reality, we tend to eat and drink a whole range of food while we drink alcohol. The calories in steak and chips followed by tiramisu will be used by the body preferentially. The alcohol all turns to fat.
And there’s the problem. If you repeat the process, with a couple of glasses, the fat deposited in the liver will never get used. We gradually gain weight and the liver gets fatter.
Does Fasting Help?
After it has finished metabolising the meal, the liver is likely to have a full load of glucose plus the abovementioned fat.
The glucose will be burned first, but the liver only contains about 100 grams. That’s 400 calories. Burning 80 calories an hour, that will all be gone in about 5 hours.
Once the glucose is gone, the liver is free to start burning liver fat. Luckily, the liver recognises that the liver fat is undesirable and will tend to dispose of it before burning any fat stored elsewhere in the body.
Allowing an extra 3 hours for the liver to deal with the non-alcohol part of the meal and provided you have really fasted and haven’t eaten anything the next morning, things could be back to normal in about 16 hours after you finished the meal.
If you finished the evening meal at 10pm you might have cleared the system by about 2pm the next day. Ready to start again!!