Leah:

Hello and welcome to the Ideal Nutrition Podcast. I am Leah Higl and today we’re diving into the question, how much does alcohol actually affect muscle growth? So in this episode, we’re going to break down what the research says about alcohol’s impact on things like muscle recovery, protein synthesis and things like that. And whether the occasional drink really matters in the big picture.

Aidan:

The first place we’re to start is by talking about mechanisms. So the first one directly related to muscle growth is obviously alcohol can reduce muscle protein synthesis. It can also increase cortisol. It can reduce testosterone in men, largely if it is a larger intake of alcohol, like smaller intakes just don’t seem to matter that much. There can obviously be other changes in behaviour. Long list, I don’t think I need to go through it, but like reduced protein intake, maybe just higher calorie intake in general, lower micronutrient intake.

It can lead to poor sleep as well directly and also indirectly in many ways. There’s a long list of mechanisms. So we’re largely going to be looking at outcomes of a lot of studies, particularly I’ve said this, I’m pretty sure on the podcast because I remember in university, one of my lecturers said that it switched off muscle protein synthesis and he was a very smart guy and I took him quite literally.

I did see a few flaws in what he was saying, but I was kind of like, I’d never heard anyone quantify it before. So I was like, I guess like lights, which just turns off. And I don’t know if that’s like giving me some bias, but it makes me care more about like, how much does this affect it? So that’s what we’re going to talk about today.

Leah:

So we’re going to dive a little bit into the research, a study that we have mentioned on the podcast previously involved a training session followed by participants being split into two groups for intake.

So after the training session, one group was just provided with a whey protein supplement. So that was like your placebo or comparison. And then the second group had the same whey protein drink, but were also provided with 12 standard drinks of alcohol. So that’s a lot. So they pretty much got their participants drunk and said, hey, here’s also a protein shake. Let’s compare just the protein shake to the protein shake plus getting wasted.

And there was a 24% reduction in muscle protein synthesis. But considering the just how much alcohol that is, I would say like a 24 % reduction is is really not too bad. And definitely not that kind of on and off light switch that you spoke about. And more like there there is a reduction, but even with really large amounts of alcohol, it’s not as significant as you may think.

Aidan:

That was the first study I read on this topic. And I remember reading that with that preconceived like light switch notion in my head. And I was like, Oh, it’s not that bad. It’s not that bad in comparison to what I thought. Um, that’s interesting. And like, could obviously look at that from multiple angles, cause it is a reduction. It’s just, I always come out through the lens of like a 100% reduction all the way through to just only being a 24% reduction.

If we have any haters out there, I don’t think we do. think most we’re pretty universally liked. But a hater could actually make a point that there wasn’t just two groups in that study, that there was actually more like there was a carbohydrate group. It was actually way more than that. But like, I’m just trying to keep this podcast friendly. Like we simplify down to those two groups, which is the only ones that actually matter for this podcast. Yeah. But I don’t know if you are a hater, feel free to leave some hate comments. Let me know. They’re for the algorithm. Five star reviews only on the podcast, but like hate comments in the DMs, please.

So the second study we’re going to talk about is a study on rugby league players. And this one wasn’t measuring muscle growth. It was more of a recovery type study looking at performance, which is a bit separate to this topic, but I also find that interesting as well. So they had the equivalent of 10 standard drinks after a game versus what they called a taste match placebo of orange juice.

I’m pretty sure I’ve heard other people on podcasts talking about this study and really criticise that being like, come on now, like it wasn’t really taste match, was it? Like you would tell the difference. But they apparently taste matched the placebo of orange juice. And then they did performance testing the next day and had noticeably worse performance. I get that this is common sense. This study was more looking at just like aiming to measure how much affected recovery. And there was just a small drop in performance. So there was a drop in performance.

Something that I often talk about with research like this that I think goes a little bit under the radar is that in performance testing with researchers, you kind of push to do the best you can. Like if you’re doing like a lifting kind of study, like they’re pushed to failure. If you’re doing a vertical jump study, they’re pushed to jump as high as they can, so on and so forth. I think in the real world, somebody who is a bit hungover, if they just had a regular training session the next day is going to perform a lot worse than they will under the conditions of somebody pushing them to complete failure still. So I think this is a bit of a fair measure and like it was just a decrease as you would expect for 10 standard drinks after a game.

Leah:

We also have a systematic review that we can point to on this topic and they included 12 different studies, but the common theme was that muscle protein synthesis was reduced by alcohol intake. But the lower the alcohol amount, the more likely it was to have a smaller impact on this, which makes sense.

That 24% reduction from the 12 standard drinks still stood out as the biggest reduction amongst all of the studies. it’s, yeah, I just think it’s interesting to think about this in the context of even if you do have some pretty big nights out. It may not be as impactful on quote on quote muscle protein synthesis, but I think the behaviour stuff kind of then comes a lot more into play and maybe the more significant impactor.

Aidan:

Yeah, and the behaviour stuff is where this gets really deep, right? Like what if you have noticeably different food choices? Like I don’t even need to list it. Hey, but like, what if you like barely ate protein that night and you just drank or whatever, then you got really poor sleep and then you ate completely differently the next day. You didn’t really train when you normally would have trained. Like there’s so many things that obviously matter here.

Talking directly about a few things. So one is that that 24% reduction from such a large amount could be interpreted however you like. For somebody who wants to have a few drinks here and there, it’s probably not really a big deal. For somebody focusing on maximising things, obviously less is best. I have an interesting thought that I’ve, I have thought about this for a long time. So I saw somebody on social media once, say, and they were coming from the perspective of they had previously been really into like evidence-based nutrition.

And then they found themselves more in like the high performance crowd to a degree of just like obsessing about getting everything they can. And they put out this line that was like, you should be cautious of the nothing matters crowd. And I thought about that a lot in relation to, I remember when I learned about flexible dieting and if it fits your macros and I kind of learned that like, it doesn’t really matter that much where you get your protein, fats and carbs from a body composition perspective.

Obviously when we’re looking at performance recovery, all these other things like micronutrients, polyphenols, all these other things matter. But I remember seeing quite a few people in the flexible dieting community talk about how they were like subbing out some of their carbs and fats for like two drinks and being like, this will have no impact on my body composition. And it’s interesting because the further you get into the nothing matters crowd, the more you start to think that way.

Whereas somebody who’s like obsessed with optimising absolutely everything would see the huge flaw of that being like, well, obviously that is going to reduce muscle protein synthesis to some degree. Above two standard drinks, it’s probably, if it’s closer to going to sleep as well, it’s probably going to affect sleep. It’s probably going to affect a bunch of other stuff as well. So you can take of this what you want. Like if you’re obsessing about doing everything you can, less is best, but there’s also flexibility in here too.

Leah:

This has been episode 203 of the Ideal Nutrition Podcast. If you haven’t yet left a rating or review, it’s always so greatly appreciated that you do so, but otherwise, thanks for tuning in.