Aidan:
Hello and welcome to the audio nutrition podcast. My name is Aidan Muir and I’m here with my co-host, Leigh Higl and this is episode 162, where we are going to be talking about protein supplementation questions and misconceptions. This is another one that’s loosely inspired by the ISSN series on questions and misconceptions. And more than anything, I’ve just gone with this again, because it allows us to quickly cover a bunch of topics. So that way, if you get value from any one of our answers, that’s awesome. But if there’s one that we covered that you’re not overly interested in, hopefully the next question is more relevant for you. And we’ve got a bunch that we’ll be covering today.
Leah:
The first myth we’re going to cover is protein is harmful to your kidneys, specifically high protein intakes. So our response to this is at least looking at the research as a whole, the research consistently finds that high protein diets are actually not detrimental to the kidneys when you have healthy functioning kidneys at baseline. There have been many studies in the range of that kind of two to three gram per kilo body weight per day in terms of protein intake amount for pretty decent durations. And overall, no issues with kidney function have been found. There’s been no kind of excess decline in kidney function due to that higher protein intake. So higher protein intake versus lower protein intake.
You can say pretty confidently that it has not been linked with different rates of kidney decline in healthy populations. And in terms of like higher protein intakes than that, there’s like, there’s not many reasons why someone would go above that three gram per kilo body weight amount. But the highest protein intake that has been studied in this regard was 4.4 grams of protein per kilo body weight per day for eight weeks. And even in that study with that really excessive protein intake, there were no issues found with kidney function.
So overall, they didn’t really track the markers very closely in regards to kidney function, but there was no major decline in kidney function found regardless. But it’s also, I guess, important to note that that was a pretty short duration being only eight weeks and we don’t have studies with that high protein intake that is significantly longer than that. Now, where it does get a little bit more complex is if you don’t have healthy kidneys at a baseline.
The authors of this particular study, this overview questions and misconceptions study, highlighted how research on protein restriction for kidney disease has found inconclusive results, just generally. So part that makes it complicated, it’s just not a straight answer even when there is already these poor-functioning kidneys. So for those particular cases, a personalised approach with your medical team makes a lot more sense, particularly if it’s a further progressed disease, chronic kidney disease, that is in a later stage.
So personally there is a clinical practice guide in regards to nutrition that as dietitians we do follow as our evidence-based practice clinical practice guide for chronic kidney disease. And that outlines some things like protein intake that you may want to reduce your intake of when there is declining kidney function. But again, that personalization aspect is a big thing.
Aidan:
We’ve added those guidelines into the show notes too, if anyone happens to be super interested in checking them out. Very long and boring read. I personally have read the document, but it does have some pretty clear guidelines in terms of like how much protein is recommended and stuff like that, which if you were in that situation, I think it’s worth checking out. The second myth we’re gonna cover is whether you need to consume protein less than one hour post-workout for muscle growth. We clearly know that total protein intake matters way more than this.
This is only a small detail. But if we’re gonna take a nuanced look at it, I would say that you probably wanna be consuming protein with within around three to five hours of your workout, either before or after, so within a window around the workout to absolutely maximise muscle growth if you want to be sure that you’re maximising it. When you think about that a little bit more deeply, that probably means that if you’re working out at a time of day where you’ve probably just been eating normal, relatively high protein meals throughout the day, you’re probably ticking that box without even thinking about it too hard. Where this becomes more relevant is if you were training,
Fasted for example you get up you train you haven’t eaten before training therefore because the first portion of that window you haven’t had any protein having some protein after that might make a bit more sense and That window you can suddenly start being like, okay Well, maybe it makes sense to have protein within an hour post workout in that situation. Once again, how much does this matter far less than total protein intake? But I still think at this stage of the research if you’re trying to maximise things it makes sense to pay some awareness to that type of.
Leah:
Topic number three is do you need protein supplements to meet the daily requirements if you lift weights? And this is a pretty easy one to answer. So typical protein requirements for people that are lifting weights, looking to build muscle recovery, whatnot, is 1 .6 to 2.2 grams per kilo body weight per day. And this can be met with or without protein supplements. There is likely no reason why you couldn’t get that all through food. It’s just that protein supplementation is a convenient way to get more protein and can be a useful tool to meet those higher protein requirements for strength training. So whilst you don’t need it, it is a helpful tool.
Aidan:
Can dietary protein have a harmful effect on bone health? This one, if you look at where the misconception is based on, like it starts to make a little bit of sense. So misconception is typically associated with what is known as the acid ash hypothesis. This whole acid base type balance, pH diet type situation. And if you go down the mechanisms, like you can start seeing stuff like, okay, if you created an acidic environment with the foods you eat, for example, eating a lot of potentially high protein foods, this could cause a bit of a chain reaction from the body where the body is stealing some calcium from the bone to try and balance things out.
Looking at solely from a mechanistic perspective, you can see the logic. But the thing I love about stuff like this is sometimes how easy it is to unpack this. Because although there could be mechanisms that make sense there, all we need to do is take the next step and be like, okay, what happens when people follow higher protein diets? Do we see this harmful effect on bone health that we’re looking for? Because the body is very complex. There are a lot of mechanisms going on all at once. You could use another overly simplified mechanism and go, well, isn’t a large portion bone made up a collagen, collagen is a form, like it’s a form of protein.
Like you can take mechanisms in so many ways. What we do know is that research shows that typically higher protein intakes are linked with better bone health and better bone mineral density, not worse. I like to say within reason, because there is enough of the mechanism there for me to believe that maybe if you went super, super high protein, maybe you could see some difference. I haven’t seen that. I haven’t seen research supporting that. But going back to that same thing we talked about with kidney function, it’s like, why would you be going above three grams per kilo?
There’s no benefit. There’s no further benefit. So I think weave in reason is a very safe thing for me to say. And weave in reason, it’s typically linked with better bone marrow density, not worse.
Leah:
And I feel like typically when we see those really high protein intakes, even the two to three grams, it’s in people that are strength training as well, which we know is great for bone health. So it’s like, how much does that balance out potentially?
Aidan:
Next one is, is there a limit to how much protein you can consume in a single meal? Again, this is a pretty easy one to answer in that there is no specific limit. The total protein intake when it comes to muscle building, recovery, all that kind of jazz, it’s clearly the main priority. So at a minimum, distributing your protein intake evenly across the day helps you consume sufficient total amount.
And then also takes care of timing stuff. So timing around training, just generally distributing it over the course of the day, you know, is better for muscle protein synthesis maximisation. But if you are someone who is like, I can only have 20 grams of protein per meal. That’s all I can quote on quote absorb. And you’re undercutting your total protein intake to avoid going over that certain gram amount per meal. Then it’s really missing the forest for the trees. It’s get your total protein intake, whatever requirements you have for whatever you’re doing, ideally distributed across the day, but there isn’t like a certain amount of protein per meal that you kind of cap it at.
Aidan:
Yeah, I’m a very positive guy, but one of my pet peeves is people who have been not so much anymore, to be honest, but like people who were on the whole hype train of you can only absorb 30 grams of protein. Like I saw people who were working with massive footy players putting out contents that you can only absorb 30 grams of protein.
And it’s just amazing because I’m like, you said one thing that can make athletes worse, like not only is this like wrong and like just not good information. It’s like, no, like if somebody listened to you, like they’ll just have too well for protein intake now, most likely.
Leah:
Yeah. And absorb is also like just not the right word there. It’s like, yes, meal eating occasion, there is probably an amount of protein where muscle protein synthesis like will kind of cap out or maximise, but it doesn’t mean you’re not absorbing the remainder of that protein.
Aidan:
Does consuming excess protein increase fat mass? I don’t see many people talking about this like every now and then I’ll see like comments on Instagram or TikTok saying this, but like I don’t think it’s a super common belief. Really easy to unpack. A calorie surplus would be what is leading to an increase in fat mass. If protein contributed to that calorie intake pushing you over however many you would require to maintain, then it could contribute to fat gain, but it’s not directly causing that without the surplus being present.
If you were in a deficit and consuming a lot of protein, you’re not going to be gaining body fat. I’m going to go back to back, so I’m going to do another myth. So the next one is you should have casein before bed and whey post workout. When I was on bodybuilding.com very early on, this one was a very common myth. Common thing that people were saying. I’ve talked about this on a podcast before, but like something that I just found so, so odd was there was a very common thing I saw people talking about, but I didn’t see many like evidence-based practitioners doing it themselves. Like I saw heaps of people having whey protein just because it seems like the gold standard and is one of the cheapest high quality forms of protein and all of those kind of things.
But I don’t see many people having casein before bed. And it got me just thinking about this topic. And down the line, when I was more equipped to look into this stuff myself, that was where I kind of started with a casein before bed thing being like, if somebody’s looking to optimise their results, should they have casein before bed? The logic is that casein is a slow digesting protein. So it makes sense. You’re fasting overnight, have a slow digesting protein. That falls apart very, very quickly when you account for the fact that the moment you mix whey or casein with anything, it changes the digestion rate significantly.
And even if you mix whey with milk or casein with milk and you compare them, the rate of digestion just comes out the same pretty much at that stage. You could just have a mixed meal containing multiple things more than just protein as well before bed and you’re getting that quote on quote slow digesting effect even more so than casein just by itself. So that falls apart. Addressing the fact that if you look up research, looking at casein before bed, that shows muscle growth. That is a common thing, but if you also just look at pretty much any study looking at protein before bed, you see that muscle growth too. Does that mean we should have protein before bed or we need to have it from a timing perspective?
I wouldn’t go that far. I think in a lot of cases, simply just increasing total protein intake in a lot of studies is going to lead to further muscle growth. And then timing may play a small factor, but it clearly doesn’t need to be casein based on all of the logic. And then just taking the other, like the way post-workout, we’ve kind of even just touched on the post-workout window thing already. I haven’t kind of talked about the fact that there’s been research looking at pre-workout protein versus post-workout protein where results come out the same.
So that’s part of the thing that feeds into this whole window that I kind of talked about being like, it doesn’t even matter if it’s pre-workout or post-workout because if you have a pre-workout, you’re still digesting and quote on quote absorbing post-workout as well. One of the nails in the coffin on this topic is that there’s been research looking at whey protein versus casein protein post -workout and measuring muscle growth and muscle growth has worked out the same. So in either case, it just doesn’t matter.
Leah:
The final question we’re going to wrap up on is can plant -based protein supplements work as well as whey protein? And short answer to this is yes, there are definitely some plant-based proteins that pretty well match whey protein. So some plant -based proteins can be low in relevant amino acids or quote unquote incomplete proteins, while others are pretty complete or like I said, very similar to whey protein and whey protein isolate. Some plant -based proteins do also have a lower digestibility in comparison to based options, but generally we would say that if your total protein intake is high enough, there is an abundance of all these amino acids anyway, and then it becomes a kind of non-issue. For my plant-based athletes, I tend to set protein like 10 to 20 percent higher just to take care of some of that digestibility issue.
But if we are looking at choosing a good quality plant-based option and we’re going for something like soy protein isolate, which has been shown to pretty similar anabolic effects and effects on muscle protein synthesis as whey protein. That’s kind of the gold standard or something like a pea and rice blend, which is a complimentary protein that together forms quite a decent amino acid profile. if we’re, again, if we’re going for one of those options, yes, plant-based protein supplements can work just as well as whey protein isolate in the context of an overall high protein diet.
Aidan:
Awesome, well, this has been episode 162 of the Ideal Nutrition podcast. I am always asking for reviews and ratings at the end of these things, but they literally do help so much. Every time we have like a flood of reviews coming, we massively skyrocket up the charts. It makes a huge difference. We get more listens, more downloads, all of those things. So if you do feel like doing a nice thing for us, we would massively appreciate a review or a rating from you.