How much muscle protein synthesis do you lose by drinking alcohol? This is a frequently asked question, but one that has a multiple variables that affect the answer. What are your goals? How much alcohol do you drink? When do you drink in relation to your workouts? What type of alcohol do you prefer? How frequently do you consume alcohol? All of these variables play some role in the ultimate effect alcohol has on strength and muscle hypertrophy.
To answer these questions, we first must review what we know from peer-reviewed scientific research. One of the most frequently reviewed articles about alcohol and protein synthesis studied heavy alcohol intake shortly after resistance training. Parr showed in this scenario that muscle protein synthesis decreased 37% after “binge” drinking and 24% even if the drinking was preceded by 25 grams of whey protein and repeated at 4 hours post-workout. This study examined alcohol intake immediately after resistance training and measured protein synthesis at 0, 4 and 8 hours post-training.
There is also some literature that evaluated a moderate amount of alcohol intake and its effect on fat loss and lean mass. A 10 week study comparing an alcohol free group and a group who consumed 2 beers a day or an equivalent amount of Vodka, showed that there was no difference between the groups when fat loss and increases in lean muscle mass were considered. Each group participated in an identical HIIT exercise program. The findings suggest that there is an absolute amount of alcohol that may be necessary to affect muscle building and at lower levels of intake the effect is minimal at worst.
A second study that evaluated two different volumes of alcohol and their effect on protein metabolism showed that the moderate amount (2 glasses of wine) had a minimal negative effect, while a significantly larger amount (5 glasses of wine) had a much greater decrease in protein metabolism. The study also appears to show that the decrease in hepatic protein metabolism has a linear relationship to the amount of alcohol consumed.
A study that evaluated concentric, eccentric and isometric strength and how it relates to alcohol intake was published by Barnes that measured strength loss after muscle damage incurred by eccentric lifting. Participants were split into 2 groups consisting of a group that drank alcohol after the lift and those who drank an equivalent non-alcoholic drink. The amount of alcohol was 1 gram per kg body weight ( the equivalent of 5-6 beers for an 80 kg subject). The study found a statistically significant decrease in peak strength in the alcohol group up to 22%. A follow up study by the same group with an identical study structure but a more moderate amount of alcohol (equivalent of 2-3 beers for an 80 kg subject) showed no negative effect on peak strength when compared to the non-alcohol group.
So the immediate limitations of protein synthesis associated with drinking alcohol seem somewhat predictable although further research is needed. There seems to be a definable amount of alcohol that may have only a limited negative effect on muscle building. But before we try to estimate that amount, let’s look at the other metabolic consequences that come with occasional alcohol intake. We will look at its influence on testosterone and cortisol levels, as well as how it affects fat loss and sleep.
The role of testosterone in muscle hypertrophy and strength training is well documented. The mechanism by which endogenous and exogenous testosterone works in poorly understood. Certainly, there is evidence that exogenous testosterone (supplied outside the body’s production) is dose-dependent, meaning the more you have the more effective it is. So anything that lowers testosterone should be detrimental to muscle growth. Valimaki showed that a significant amount of alcohol (1.5.grams/kg) decreases testosterone up to 23% for almost 24 hours. His study also showed a decrease in growth hormone and an increase in cortisol. We’ll get to those in a minute. A study that had participants drink a moderate amount of beer (3 a day) showed little change (6.8%) in testosterone suggesting that only heavy drinking would cause a significant negative effect on muscle growth due to lowered testosterone.
A brief discussion of cortisol and its connection to muscle protein synthesis would help our understanding of the role of alcohol in weightlifting. Cortisol is a steroid hormone made in the adrenal glands that has a huge array of regulatory functions in the body. For our purposes, it is catabolic and capable of breaking down muscle as a source of energy. It also inhibits protein synthesis. So it prevents increasing muscle mass not only by blocking production but also breaks down existing muscle. It tends to be produced by increased stress and lack of sleep. As mentioned in the Valimaki study above, “binge“ drinking can increase cortisol 36% in the first 12 hours after drinking. Although the isolated effect of this increase in cortisol has yet to be studied, it can only lead to a decrease in the body’s ability to build muscle.
Although fat loss is a peripheral consideration to the weightlifter when discussing building muscle, it can not be ignored for optimal results. In general, more muscle and less fat are the typical goals for resistance training. Alcohol is undeniably counterproductive to weight loss. For those who follow macros, the understanding that calories per gram of fat, carbs and protein is fundamental. Protein has 4 calories per gram, carbs 4 calories per gram and fat has 9 calories per gram. If you’ve ever done the math for a bottle of beer, the macros don’t add up to the total calories. For example, a light beer that has 99 calories, may have 4 carbs, 0 fat and less than 1 gram of protein. Somehow there are 80 calories unaccounted for. These calories come from alcohol which account for 7 calories per gram. So alcohol is the example of empty calories that must be burned before other sources of energy, such as fat, can be utilized. Unfortunately, the body prioritizes burning the alcohol calories first. There is no capacity to store alcohol so it is maintained in the body water volume until it is metabolized. It is not under the control of any hormones, like the other nutrients. To make matters worse, research shows we tend to eat more while drinking alcohol (I know it’s an animal study but here you go). Lastly, the food typically associated with your temporary loss of restraint from over-eating is usually not of the healthy variety. So the immediate effects of alcohol are, at a minimum, counter productive to fat loss. Alcohol metabolism is linear or steady state and is much more slowly processed than most drugs which are metabolized exponentially. Read more about the deeper discussion here. The bottom line is that, there is a lasting effect of alcohol ingestion after you stop drinking.
We are all aware that muscle recovery occurs over 24 -48 hours and sleep plays a big role in that process. We know that alcohol decreases testosterone and increases cortisol, both of which have a detrimental effect on muscle recovery and growth. Alcohol also decreases REM sleep. Whether or not this sleep interruption is the independent source of the testosterone and cortisol changes, or if there is a collective effect of alcohol in addition to the sleep deficit, has not been studied. Nonetheless, the detrimental consequences of alcohol in this regard are undeniable.
Tips for alcohol use and muscle growth
So if you’re not convinced that jumping on the wagon of complete sobriety is for you, what can you do to minimize the effects of an occasional night of drinking on your quest for building muscle. First, make drinking an occasional or special event. Avoiding frequent nights on the town is an important start. Next, completely avoid binge drinking. Every study mentioned in this article that showed unequivocal findings about the destructive outcomes alcohol produces with respect to protein synthesis are associated with heavy drinking. There is good reason to believe that ingesting 25-30 grams of protein following a workout but before drinking will lessen the effect of alcohol on recovery. A general recommendation would be to take in a meal of quality protein after a workout, wait approximately an hour before drinking alcohol and limit yourself to around 3 beers or the equivalent. There are multiple studies listed above that would support the idea that such plan would have little or no effect on your recovery or your ability to perform in subsequent workouts. For most reliable outcomes, try to do this sparingly. There is little literature to evaluate the effects of frequent alcohol ingestion on a chronic basis as it would relate to a weightlifter, powerlifter or bodybuilder.
For the most dedicated weightlifter, abstinence is the safest choice. As for me, I think I’ll have a couple of beers.