Ethanol AKA Poison
Unlike fat, protein and carbohydrates, the human body cannot store alcohol. This is significant because one of the intermediate products of alcohol metabolism, acetaldehyde, is extremely toxic to our system.
Whether we have one drink or twenty, our body will cease metabolizing other fuels and direct its energies into converting this metabolic poison (acetaldehyde) into acetate (Acetyl CoA), which we can oxidize.
Fair enough. Metabolizing alcohol ahead of the other fuels makes sense because it keeps us from poisoning ourselves. But how does that make drinking a case of beer any different than drinking a 26 oz. bottle of vodka?
The Double Whammy
The big physique wrecking impact of beer and mixed drinks stems from ingesting alcohol + carbohydrates coupled with our extremely limited capacity for carbohydrate storage.
This isn’t to downplay the significance of high blood glucose, which can be toxic over time; however, the short term effect of excess glucose have far more to do with promoting fat storage than it does with contributing to organ failure.
Most humans have a total glycogen storage capacity of between 300-700 g. You’d think this would leave ample space for a few extra grams of carbohydrates ingested in the form of a drink or two but you’d be wrong.
Our current carbohydrate intake is normally 30%-65% of total calories. This means that even on a 2000 kcal diet, you are being told to consume anywhere from 150 – 325 g carbohydrates/day.
Remember, even a single beer provides 10-15 g of carbohydrate but let’s be honest, who stops at a single beer? A more representative night of drinking might be closer to 6 beers, which means you’ve got an additional 60-90 grams of glucose to deal with.
At rest, an individual with a normal blood sugar has only ~ 5 g (1 tsp) of glucose dissolved in their blood. Do the math and you’ll see that six beers provide 12-16 times the glucose your body needs to maintain homeostasis!
Since large elevations in blood glucose are toxic (admittedly to a lesser extent than alcohol), now we’ve got a serious dilemma. Not only must our bodies deal with all this alcohol energy, but we have to find some way of clearing the excess blood sugar as well.
The solution: either oxidize the glucose or store it (and if glycogen stores are full, our bodies will happily use the excess glucose to create new body fat).
Normally, following a meal containing a large amount of carbohydrates, fat burning would get suppressed for a period of several hours to allow you to metabolize the glucose instead. Alas, when you drink beer or a mixed drink, you’ve got to deal with the alcohol first. As a result, you wind up burning the alcohol and shuttling the glucose into storage.
Any idea which fat storage sites tend to take up carbohydrate-based energy most readily?
Yep, you guessed it: the belly.
Needless to say, combining two nutrient-devoid fuel sources is never a good idea.
So to summarize our hierarchy of metabolic fuels. Your body body will attempt to oxidize fuels in the following order:
- Alcohol: extremely toxic in the blood, must be dealt with ASAP.
- Carbohydrate: toxic in large quantities in the blood, needed in small amounts.
- Fats: free fatty acids are the preferred fuel source at rest.
- Protein: amino acids should rarely contribute more than 5-10% of total energy needs.
[Note: metabolism isn’t so cut and dry in real life, but you get the idea]
How much damage can you do?
Clearly, large amounts of alcohol and/or carbohydrate are not conducive to helping us return to a fat burning state. But what about more modest amounts like 3-4 drinks in a night, do they create the same kind of metabolic disruption?
Short answer: yes.
By now you’ve got a basic understanding of metabolism in general. You’ve also seen why your body must metabolize alcohol before the other fuels. Now we’ve got to look into the time course of alcohol metabolism.
Obviously there isn’t a single answer as everyone’s metabolism differs. Alcohol metabolism in particular will vary by race, gender, body size, food status, age etc. So while I can’t give you an exact number, I’ve located some research to help clarify the issue.
Adapted from Wilkinson et al., Journal of Pharmacokinetics and Biopharmaceutics 5(3):207-224, 1977
Yikes, even as few as four drinks can provide fuel for up to 7 hours (our liver can only metabolize between 7-15 g/alcohol per hour).
Considering that 4 drinks is a pretty modest night for many individuals and very few people limit themselves to spirits or wine, then its conceivable that you can easily have 7+ hours of alcohol to metabolize IN ADDITION TO whatever glucose or fat you slam into the system.
Are you beginning to appreciate the magnitude of the issue?
Let’s revisit our 6 drinks in a night scenario. If you are a slow metabolizer of alcohol (7 g/hour) and begin drinking your 6 beers (78 g alcohol, 72 g carbohydrates) at 9 PM, you’ll still trying to get through the alcohol by 8 AM the next morning.
Toss in the extra glucose to contend with and you may be lucky to return to oxidizing stored body fat by some point around noon!
Of course, this presupposes that you didn’t stop in for pizza after the bar, didn’t decide that grabbing a McDonalds breakfast will sop up the remaining alcohol or decide that a “the hair of the dog that bit you” is the ideal hangover solution.
By way of comparison, if you have a relatively lower carbohydrate dinner around 7 PM, you’ll return to oxidizing fat by ~10 PM at the latest and will spend the entire night in a pro-fat burning state.
A Final Word
Obviously, the point of this post isn’t to convince you to never drink again. Frankly, you are all adults and can decide for yourselves whether alcohol is going to be part of your lifestyle. Rather I just wanted to highlight the choice you have to make between instant gratification and long-term health.
If you place more value on having a daily nightcap, then you’ll also have to accept the extra 5 lbs of fat that tends to accompany such a habit. A glass of wine might be good for the heart, but it’s not great for the waistline.
Conversely, if you place greater emphasis on seeing your abs year round, then you’ll definitely want to limit your forays into the world of alcohol to special occasions and opt for physique friendlier choices when you do.
Remember, when it comes to booze and having a beach body, you can’t have it both ways.
This blog was an adaptation from this full article.