Does drinking alcohol impact your muscle growth?

You don’t need to be a certified strength and conditioning specialist or a registered dietitian to know that proper training and nutrition are required in order to build muscle, gain strength, and attain an enviable physique.

Still, there are those times when we deviate from our healthy lifestyle, which usually manifests in the form of going off of our diet plan.

Now, I think we’d all agree that the occasional handful of fries, slice of pizza, or chocolate milkshake won’t completely derail our progress (just don’t let the paleo and keto guys hear that!).

But, one “off plan” food that still garners considerable debate is alcohol.

You’ve likely heard that drinking alcohol hurts your gains. 

But, how bad is the damage?

Will even a single drink completely sabotage your path to gains, or can you get by with the occasional hit of “social lubricant” and still achieve your goals?

Let’s find out.

What Happens When You Drink Alcohol?

We’ll get the ball rolling by discussing what actually happens when you consume alcohol, be it beer, wine, or liquor.

Before we get into the biology of it all know two things from the get go[1,2]:

• Your body can only metabolize a certain amount of alcohol each hour, regardless of how much you drink.
• The amount you can metabolize depends on a wide variety of factors including body mass and the size of your liver.

Speaking of the liver, it along with the stomach, pancreas, and even the brain contribute to the metabolization of alcohol.[3]

Now, when you drink alcohol, the body prioritizes metabolizing the alcohol (ethanol) first.

The reason for this is simple -- ethanol is toxic to the body.[4] As such, the body’s going to focus first and foremost on eliminating any potential threat to its survival.

To metabolize and eliminate the alcohol, your body relies heavily on two enzymes:

• alcohol dehydrogenase (ADH)
• aldehyde dehydrogenase (ALDH)

Together, these enzymes help break down ethanol molecules into smaller molecules that can more easily be eliminated.

As we mentioned above, the vast majority of alcohol consumed is metabolized in the liver by alcohol dehydrogenase.

Alcohol dehydrogenase transforms the alcohol molecule into another toxic compound called acetaldehyde (CH3CHO), which also happens to be a known carcinogen. 

Doesn’t sound so good for alcohol and gains, does it?

However, acetaldehyde is around for only a short while before it’s rapidly metabolized by aldehyde dehydrogenase (ALDH) into a less hazardous compound called acetate (CH3COO-). 

Subsequently, acetate is broken down to carbon dioxide (CO2) and water by tissues other than the liver and used for energy.

It’s also worth mentioning that acetate is also broken down into acetyl-CoA, which can also be used for energy.

However, this process if very energy-demanding for the body.

What we mean by that is that while alcohol is said to contain 7 calories per gram, the real calorie “payload” per gram of alcohol is 5.1 calories.[5] This is due to alcohol’s rather high thermic effect.

Also, contrary to what you’ve likely heard, alcohol isn’t readily converted to body fat, either. Simply put, it’s simply too “expensive” from an energy standpoint in the body.

It’s worth noting that the Acetate and Acetyl-CoA taken up by your cells from the breakdown of alcohol does instruct your body that it has plenty of energy, and thus doesn’t need to rely on its own energy stores. So, in this case, alcohol is more of a suppressor of fat burning rather than a direct fat gainer.

What’s more likely the cause of your fat gain when you drink is the pile of cheese fries, nachos, and chicken wings you eat while drinking. But, that’s a topic for another article.

What we’re concerned with here are the effects of alcohol and muscle growth.

So, let’s get on with it!

Does Drinking Hurt Muscle Gain?

To begin to answer this question, let’s first review what happens when you lift weights -- you damage them.

In the hours and days after training, your body sets about repairing the damage done during training as well as making them bigger, stronger, and more resilient to future stressors, provided you consume enough total protein and calories each day.

The biological process doing the “repair work” is called muscle protein synthesis, or MPS for short, and it goes into overdrive in the hours immediately following training and remains elevated for some time.

However, when you drink alcohol, muscle protein synthesis rates are decreased, as are testosterone levels and mTOR kinase activity[6] FYI, mTOR kinase is an enzyme that serves as a key signal for muscle growth.

But that’s not all, the following events also occur after you drink alcohol:

• Reduced glycogen resynthesis
• Decreased post-exercise inflammation (in the case of exercise recovery, inflammation is a good, and vital, thing)  
• Increased myostatin (a protein that inhibits muscle cell growth and differentiation)
• Impaired insulin and IGF-1 signaling

You don’t need to have a PhD in anatomy and physiology to know that these side effects aren’t the best for building muscle.

But, the more important question you should be pondering (at least if you want to have the occasional drink) is to what degree are these effects present and how much alcohol can you consume before these adverse effects take place.

For that, we can turn to a recent study that investigated those very questions.

Alcohol, Testosterone, and Muscle Growth

Study #1

The first study of note comes from 2014 and included 8 physically active males who completed three experimental trials consisting of:

• Resistance training (8×5 reps leg extension, 80% 1 repetition maximum), followed by
• Continuous cycling (30 min, 63% peak power output ), and 
• High intensity interval cycling (10×30 s, 110% peak power output). 

Sounds fairly intense, doesn’t it?

Immediately after training as well as 4 hours post-exercie, the men were given a 500mL post workout supplement containing either:

• Whey protein (supplying 25g protein),
• Alcohol + whey protein (note, the amount of alcohol included was 1.5 g·kg body mass−1, which is equal to roughly 12 standard drinks)
• Energy-matched cocktail of carbohydrate and alcohol (25 g maltodextrin). 

Without even getting into the muscle growth side of things, these guys were given A LOT of friggin’ alcohol!

Also of note, the men consumed a carbohydrate meal (1.5 g carb/kg body weight) 2 hours post-exercise. 

Researchers collected muscle biopsies from the men 2 and 8 hours post-exercise.

Unsurprisingly, researchers noticed that consuming the equivalent of 9 servings of alcohol post-workout reduced MPS rates by 24%.[7]

To put that in perspective, let’s say you were dieting and utilized a very aggressive energy deficit along the lines of a 40% reduction in calories. Research has shown that this considerable energy deficit reduces MPS rates by 36%.[8]

Basically, this study shows that getting blitzed after your workout can impact your body’s ability to repair and build muscle as much as spending a day in a massive calorie deficit.

Study #2

More recently, a 2017 study involved 19 participants (10 male and 9 female) in a crossover trial, meaning each participant performed the test using both an alcohol and placebo trial.[9]

The exercise trial in this study consisted of six sets of 10 Smith machine squats using 80% of their respective 1RM with 2 minutes rest between sets. Testing periods were separated by 28 days to reduce the possibility of any potential interference effect from the alcohol when the subjects ran the placebo condition.

And, similar to the previous study, researchers collected muscle biopsies from the subjects. 

In this case, biopsies of the vastus lateralis were scavenged from the participants pre workout as well as 3 hours and 5 hours post-exercise.

From 10-20 minutes post-workout, subjects consumed either alcohol or placebo in an artificially sweetened, calorie-free beverage.

The alcohol used for the alcohol condition was Smirnoff vodka diluted in water to a concentration of 15% absolute alcohol, yielding a dose 1.09g of alcohol per kg of fat free body mass.[9]

Note: this amount of alcohol is equal to roughly five shots of vodka for an average sized male.

Now, obviously, you’d be able to notice if you had the placebo or vodka post workout supplement, but here’s the interesting part -- researchers smeared the rim of the glass with a small amount of alcohol for both conditions to dupe the placebo group into thinking they had alcohol too.

So, what did they find out?

Women are luckier than men when it comes to getting schnockered post workout.

By that, we mean that researchers observed that women aren’t nearly as affected in terms of mTOR signaling as men when it comes to consuming alcohol post workout.[9]

The authors do state, however, that resistance training may help prevent mTOR signaling from dropping below baseline while consuming alcohol, although it won’t increase it above baseline.

Basically, crushing a workout and then drinking is better than just drinking and not training at all.

And, if you’re a woman, you’re less likely to be impacted by drinking after a bout of resistance training than men.

So, what does this mean for guys who lift?

Well, previous research shows that drinking whey protein can limit the detrimental effects of alcohol consumption on mTOR signaling, and subsequently muscle protein synthesis.[7]

Other research indicates that light drinking (0.5 g of alcohol per kg bodyweight doesn’t appear to adversely impact recovery from even very intense exercise.[10]

Furthermore, additional studies show that consuming ~4 drinks doesn’t impact strength recovery, though it does decrease testosterone levels.[11]

The Bottom Line on Drinking and Muscle Growth

So, what can we learn from the studies on alcohol and muscle growth?

Re-enacting your college partying days post-workout is a bad idea for muscle growth...all the more so if you’re drinking consists of jungle juice.

Provided you’re not in the habit of binge drinking after a workout, one or two drinks is fine. The current body of evidence suggests that the effect of consuming small quantities of alcohol on your ability to build muscle and strength is minimal.

References

1. Edenberg, H.J. The genetics of alcohol metabolism: Role of alcohol dehydrogenase and aldehyde dehydrogenase variants. Alcohol Research & Health 30(1):5–13, 2007.
2. National Institute on Alcohol Abuse and Alcoholism. Alcohol Alert: Alcohol Metabolism.No. 35, PH 371. Bethesda, MD: the Institute, 1997 http://pubs.niaaa.nih.gov/publications/aa35.htm
3. "NIAAA Publications." Brochures and Fact Sheets | National Institute on Alcohol Abuse and Alcoholism (NIAAA), pubs.niaaa.nih.gov/publications/aa72/aa72.htm.
4. Ahmed, F. E. (1995). Toxicological effects of ethanol on human health. Critical Reviews in Toxicology, 25(4), 347–367. https://doi.org/10.3109/10408449509021614
5. Suter, P. M., Jequier, E., & Schutz, Y. (1994). Effect of ethanol on energy expenditure. The American Journal of Physiology, 266(4 Pt 2), R1204-12.
6. Lang, C. H., Frost, R. A., Deshpande, N., Kumar, V., Vary, T. C., Jefferson, L. S., & Kimball, S. R. (2003). Alcohol impairs leucine-mediated phosphorylation of 4E-BP1, S6K1, eIF4G, and mTOR in skeletal muscle. American Journal of Physiology. Endocrinology and Metabolism, 285(6), E1205-15. https://doi.org/10.1152/ajpendo.00177.2003
7. Parr EB, Camera DM, Areta JL, et al. Alcohol ingestion impairs maximal post-exercise rates of myofibrillar protein synthesis following a single bout of concurrent training. PLoS One. 2014;9(2):e88384. Published 2014 Feb 12. doi:10.1371/journal.pone.0088384
8. Hector, A. J., McGlory, C., Damas, F., Mazara, N., Baker, S. K., & Phillips, S. M. (2018). Pronounced energy restriction with elevated protein intake results in no change in proteolysis and reductions in skeletal muscle protein synthesis that are mitigated by resistance exercise. FASEB Journal : Official Publication of the Federation of American Societies for  Experimental Biology, 32(1), 265–275. https://doi.org/10.1096/fj.201700158RR
9. Duplanty, AA, Budnar, RG, Luk, HY, Levitt, DE, Hill, DW, McFarlin, BK, Huggett, DB, and Vingren, JL. Effect of acute alcohol ingestion on resistance exercise–induced mTORC1 signaling in human muscle. J Strength Cond Res 31(1): 54– 61, 2017
10. Barnes, M. J., Mundel, T., & Stannard, S. R. (2011). A low dose of alcohol does not impact skeletal muscle performance after exercise-induced muscle damage. European Journal of Applied Physiology, 111(4), 725–729. https://doi.org/10.1007/s00421-010-1655-8
11. Haugvad, A., Haugvad, L., Hamarsland, H., & Paulsen, G. (2014). Ethanol does not delay muscle recovery but decreases testosterone/cortisol ratio. Medicine and Science in Sports and Exercise, 46(11), 2175–2183. https://doi.org/10.1249/MSS.0000000000000339