I’ve been doing intermittent fasting for a while now, and I have to admit I did break my fast with alcohol a few times. I know when I do it that it’s not a good idea, sometimes I even broke a 24-hour fast with alcohol and that really didn’t suit me. But still, I wondered, how bad is it break a fast with alcohol?
Breaking a fast with alcohol will have several ill-effects on the body. When fasting, the pyloric valve between the stomach and the small intestine is wide open. Alcohol will go directly into the intestine and overload the liver. It will concentrate all its efforts on getting rid of the alcohol, while not processing the food you’ll eat properly.
That’s not all there is to it. I’ll take a deeper look at the way alcohol is metabolized versus regular glucose, the other side effects of alcohol on a fasted body, what you should do to minimize the damages, what effect might sugar have when compared to alcohol, etc.
So, sit back and get ready to get into some hard science and pretty depressing stuff if, like me, you like to party on weekends.
How alcohol is metabolized in the body
How alcohol is metabolized is a big factor to understand exactly what happens when you drink alcohol when compared to a basic non-toxic carbohydrate.
Since I’ll also talk about fructose later in this article, I think dissecting the different ways glucose, ethanol, and fructose are broken down in the body might be a good way to fully understand the differences and the danger of the later.
So, here’s how pasta or a slice of bread will be handled by the liver:
- 80 % of it will actually be metabolized over all your body
- Only 20% of it will hit the liver
- The liver will start by stimulating the pancreas to make insulin
- The first process will be to store most of the glucose as glycogen in the glycogen store. Basically, it’s the energy store
- Then the rest of it will be metabolized as pyruvate which then enters the mitochondria
- Mitochondria will then burn most of the pyruvate as energy
- Depending on the amount, there might be some leftovers as citrate
- This citrate will be transformed, through a process called de novo lipogenesis, in English new fat making
- Since the liver doesn’t want a bunch of fat lying around, it’s transformed into VLDL and then stored into fat tissues. VLDL is one of the main factors of heart disease
Reading this, you might think twice the next time you’re proposed with a slice of bread. But keep in mind that the amount of glucose that will be turned into VLDL is actually really small with a non-toxic carbohydrate. Around 1/50 of it.
Now, what exactly happens to the body when you’re drinking alcohol? Here’s the whole process of how your liver breaks down ethanol:
- 10 % will be processed in the stomach and intestines, then 10% in the kidneys, muscle, and brain. I’ll talk about all that later
- So, most of the ethanol is metabolized by the liver as it’ll be considered a toxin
- The liver will actually have to work twice as hard; ethanol will diffuse itself in the cells (no need for insulin) and an enzyme called dehydrogenase will turn it into acetaldehyde
- Acetaldehyde is 30 times more toxic than ethanol. Why would the liver produce them? Because it’s a much simpler molecule to break down
- A second enzyme called aldehyde dehydrogenase will break down acetaldehyde into acetate, which is basically water and carbon dioxide
- Some of the acetaldehyde will result in reactive oxygen species (ROS) staying in the liver. Those, in the long term, can damage the proteins in your body, causing cancer, and are a key factor of aging
- Acetate will then enter mitochondria resulting in overload. Since it cannot be used as energy, it’ll be turned into citrate
- Citrate will mostly be turned into fat through the same process explained earlier and most of it will be visceral fat. The fat surrounding your organs (commonly known as beer belly)
- Some of it will be exported as free fatty acids, which will go in the muscles, causing muscle insulin resistance
- Some of the fat will stay in the liver as lipid droplets, which on the long term can cause alcoholic fatty liver disease
- Ethanol + ROS + lipid droplets (excess acyl-CoA) will then activate an enzyme called JNK-1. This enzyme works as a bridge between metabolism and inflammation. And this can then result in the deactivation of the IRS-1 insulin receptor, causing insulin resistance in the liver. Since the receptor is deactivated, the pancreas will end up pumping more insulin
What all that means is that, when compared to non-toxic glucose, alcohol, more precisely ethanol, ends up as VLDL (fat) in a much greater amount. And I’m not even talking of all the side effects.
Around 80% is metabolized in the liver, against 20% for carbs, none of it is burned into energy, against most of it for carbs. So, yeah, among other things, alcohol makes you fat, big news!
It doesn’t stop there. An enzyme called catalase, combined with another set of enzymes breaks down ethanol to acetaldehyde and goes to the brain when metabolized. This allows acetaldehyde to combine with neurotransmitters, creating tetrahydroisoquinoline (TIQ for short). There are still lots of research on this, but this might contribute a great deal to addiction.
Another component involved when handling alcohol is an antioxidant called glutathione. It’s used to neutralize the poison in ethanol. Your body makes a store of glutathione and when you drink a lot, this store might get depleted. This results in the poison in alcohol making you groggy and hangover.
Fasting is known to refill glutathione stores, which might help you fight the poison on a hangover but restoring these stores might take more than a few hours. You could quicken the process by taking glutathione capsules to help with a hangover.
What happens when breaking a fast with alcohol
As I said in my introduction if you still have doubts about it: drinking alcohol breaks a fast for sure. Alcohol contains seven calories and induces a strong metabolic response to process it. So, it breaks a fast.
Now, when you’re fasting, you’re not getting any foods and any nutrients. In this state, the pyloric valve, which is a valve between your stomach and intestine, is wide open.
This valve allows food in the intestine when you’re ready to eat and absorb nutrients. If you’re full, the valve closes and new food won’t go into the small intestines.
What’s important to understand here, is that your stomach as a few square feet of surface to absorb nutrients. While your small intestine has a surface of thousands of square feet.
So, the small intestine will absorb nutrients much, much faster and efficiently than the stomach. Alcohol, like fat, protein or carbs, could be considered as another macronutrient.
When you drink alcohol after a fast, with the pyloric valve wide open, your body will absorb alcohol really fast, rising up your blood alcohol, making your drunk more quickly. Which might be cool for you, but not for your body.
The enzymes that normally are at work to break down alcohol won’t be able to keep up since you’ll be absorbing it so quickly. So, the liver is going to prioritize metabolism and alcohol over everything else. Meaning any food you’ll consume with alcohol, or after drinking, will be put back and not properly processed.
All the added benefits that your body usually gets after a fast, all the fat-burning efficiency of it will go right out of the window.
Alcohol will also slow down catecholamine response, cortisol, and adrenaline. Which explains why you don’t have the same reflexes for example. When fasting, some of the fat-burning effects of it comes from adrenaline and noradrenaline, which is part of our central nervous system.
A lot of the benefits and fat burning effects you’d get from fasting comes from the stimulation of the central nervous system. So, drinking alcohol might actually negate some of those effects and benefits.
What if you want to drink on a fasting day
First off, don’t break your fast with alcohol if you can avoid it. You know how it works, you know what it does to your body, it’s not good.
What you might want to do is have a small carbs intake when breaking the fast, before having a drink. This might help on two important levels:
- It will start closing the pyloric valve
- It will help put glycogen into the liver
This second effect will allow the liver to combine glycogen with acetaldehyde to actually slow down and soften the absorption. It’s not a guaranteed win of course and you shouldn’t pack with carbohydrates.
It’s advised to have between 20 to 30 grams of carbs for this to be effective.
Regarding the different types of alcohol and which ones you should prefer if you want to have a drink on a fasting day, it actually depends on its fermentation. Some alcohols might have a lot of toxic by-products from the fermentation itself. This is not exactly a clean process and the more the alcohol is distilled, the cleaner the result.
So, it’s advised to prefer triple or even quadruple distilled alcohol like vodka, gin, tequila, whiskey, and other distilled spirits. When it comes to wine, it’s really not ideal especially red wine or sweet white wine. You should also try to avoid wines that contain sulfites since it would be adding toxic nutrients and putting more work on the liver.
But brace up if like me you’re a beer lover: it’s by far the worst alcohol you can drink on a fasting day. Or if you want to avoid a hangover the next day. It has the most toxins of any alcoholic beverage.
I don’t know if you noticed, but often time, craft beer will induce more grogginess, headaches and overall hangover effects than industrial beer. That could come from more by-products leftovers in the “homemade” brewery process.
That won’t stop me from drinking those, I can tell you that, but when looking at the science, it figures.
What about soda, candy, sugar
Most of what I’ve talked about concerning alcohol is actually also true for sugar. Not the side effects impacting the brain and slowing down adrenaline and all that stuff.
But sugar, more specifically fructose, which is in equal part to glucose in sucrose, is broken down in a different way than standard carbohydrate or ethanol.
Here’s how sucrose is metabolized:
- First off, fructose, like ethanol, is not necessary for the body, so it’s treated as a foreign substance and 100% of it goes to the liver
- None of it is turned to glycogen, it’s all transformed into pyruvate which then enters mitochondria
- None of it is burned off as energy, which overloads the liver cells mitochondria
- It’s then exported as citrate and the process of de novo lipogenesis creates new VLDL fat and mostly visceral fat
- The leftovers VLDL stays in the liver, same as alcohol, which can lead to NAFLD, short for non-alcoholic fatty liver disease
- Like ethanol, it then deactivates insulin receptor IRS-1 which leads to insulin resistance
In the movie That Sugar Film that you can see on YouTube, they conducted an experiment eating 2300 calories a day, which is the recommended amount, solely from products marketed as fat-free, healthy and light food.
Basically, produces where fat’s been replaced with added sugar, honey or corn syrup. After only 18 days in the experiment, the patient developed non-alcoholic fatty liver disease. That is one of the leading causes of chronic liver disease in the US.
To summarize, here are the most common chronic effects of regular alcohol use. Bolded are the effects you could also get by a daily sugar (fructose) consumption:
- Blood disorders
- Electrolyte abnormalities
- Heart disease
- Cardiac dilatation
- High blood triglycerides
- Fetal alcohol syndrome
- Fatty liver disease
What about the effects of breaking a fast with soda? The body will absorb fructose more quickly, the liver will have a hard time dealing with it and will put most of its effort into handling the rush of fructose over any other task.
So, it won’t be as bad and damaging, but it still is a bad idea to break a fast with coke or with candy.
Should I fast on a hangover? Even though I talked about glutathione store being depleted on a hangover, and fasting restoring it, as I said in my article on the subject – check it out for a lot more detailed answer – nothing clearly indicates that fasting would have either a negative nor a positive effect. You should drink a lot, try to keep active and listen to your body.
Should I eat fruit if fructose is so bad? I like fruit but regarding health, it wouldn’t be a food I would recommend eating on a daily basis. Compared to vegetables, it’s generally higher in carbs and it contains fructose. But it’s also full of fibers. Meaning it’ll reduce the rate in which your body absorbs fructose. The liver will then be able to handle the steady stream of sugar from the fruit quite easily. And keep in mind that fiber will fill you up. Fruit juice is a whole other thing of course since all the fiber’s gone.