A while ago, I stumbled over a post on Reddit, where someone was asking about how much protein we can absorb. It’s the famous protein absorption myth. People ask this question all the time. Here’s the post: “Hey redditors, im sure all of us heard the phrase: “You should eat max 25G of protein in a meal” Some say it wont absorb well and turn into fat, Some say it causes bloating etc.. So my question is basically IS IT a myth? What if i need 200G of protein in a day? Am i supposed to divide my protein intake to 8 different mini meals/protein shakes? I would love if someone could explain or counter this limitation and the science behind it on a biological level.
I took some time and wrote a reply and wanted to share it here too but never came around to writing the article. You can see my reply if you click on the above post. You’ll find a better-written version down below and a YouTube video on my channel.
The protein absorption myth
While 25g of protein might sound a lot, it isn’t that much. And in terms of optimal protein muscle synthesis (MPS), 40g would be better as 3g of the amino acid Leucine should be present for optimal MPS (more about the calculation below). The amount of protein that optimizes your MPS is also where this idea of “absorption” comes from in the first place. It’s not about how much your body can digest, it’s about how much it can make use of in terms of building protein, i.e. have a net benefit to muscle protein synthesis.
The (simplified) protein science
While the protein absorption myth is one thing, the science is something different and goes like this (simplified): if you eat a certain amount of protein, it will switch a trigger in your body that will start MPS, meaning once this trigger gets flipped your body will try to make new muscle tissue. And the research seems to suggest that something like 25g could already start this trigger, but 40g definitely should (that is high quality, read rich in Leucine, read non-vegan protein). The exact amount really depends on the individual and the protein source and quality.
The Leucine threshold for this trigger seems to be around 2-2,5g of Leucine. As stated above optimal is around 3g of Leucine. Your typical whey protein has around 8-10% leucine. If you do the math of 30g whey, roughly 25g protein you get 2-2,5g of leucine in one serving. It’s that simple (for 40g of whey you get around 32g of protein and around 2,6-3,2 g of Leucine). You can have more protein and the spike in MPS gets a little higher but seems to flatten quickly. That is why there the myth of “not more than 25g of protein” comes from. While Leucine seems very important for triggering nutrition-based MPS, it’s not enough.
Long story short, you can absorb as much protein as you eat, but the MPS spike will flatten out at some point. this means your body will still use the protein for recovery and building muscle, maybe even as an energy source (though, that is not happening often). But the signal will just not grow further. And this makes sense if you think about it. At one point in time, there’s not much more of the signal “build muscle” you can add. You go from a whisper to normal talking to screaming it, to use a metaphor. Your body got the message and that’s the point of MPS.
Also, don’t confuse triggering MPS with actually having the essential amino acids to build muscle mass. Technically you could just drop Leucine pills and trigger MPS, but you’re missing all the remaining EAAs to actually build something (that is if you actually resistance train properly!). That’s like trying to build a house and all you have is several trucks worth of concrete and nothing else.
How much do I need?
Now we talked a lot about the protein absorption myth, where it comes from and what MPS is. You might wonder how much protein you need for optimal MPS. The amount of protein you need is a very hard question to answer, as it depends very much on you, your lifestyle and your goals.
A solid estimate is to take your bodyweight in kg and just double this number. Take me for example, I weigh around 83kg while writing this, so a good place to start would be 2*83, which makes 166g of protein. I personally tend to eat more than this number, usually floating around 185-205g of protein a day.
There’s no need to worry. There is this myth that this will destroy your kidneys or be unhealthy in whatever way, but that’s simply not what studies suggest. Rather the contrary, more protein tends to increase overall health (up to 3g per kg body weight seem to be absolutely fine). The only reason not to eat more protein rather then less is if you have a pre-existing health condition.
And please don’t confuse RDA with optimal intake and health. The RDA gives you amounts based on how much you need to not get sick or suffer from illness. This is absolutely not the same as thriving and living optimally.
In terms of MPS, make sure to spread your protein on several meals. If your goal is 160g of protein, make sure to spread it over 4 meals, allowing you to keep triggering the signal. That’s also important if you are facing a caloric deficit.
Digestion
Before we end this absorption myth, I want to talk about digestion. This is a little trickier, as it is much less black-and-white. Instead it is more like a gray-scale. If you have digestive issues from your nutrition, you are not absorbing it (properly or at all). This is a problem.
In an ideal world, you should not have any issues with your food what so ever. No gas, no bloating, no diarrhea.
None, I repeat, none of these symptoms is normal. If you have any of them, especially on a regular basis, you need to figure out which foods are causing them and why.
A common source people tend to have problems with, is whey protein powder. If that is the case, don’t eat it. There are alternatives, mainly food from animal sources (meat, eggs, dairy products), that are more than adequate to fuel your protein requirements. You don’t need any extra powders.
But it could also be the vegetables you eat, the carb sources you might need to check when it comes to bloating. Or maybe the way your lifestyle might impact your digestion. Do you eat on the go most of the time? Maybe then you need to figure out a way to take a little more time, to sit down, and give your body the chance to eat and digest the food. Maybe you are very stressed and this is impacting your digestion. Or maybe you are too sedentary and a short post-meal 10-minute walk will solve the issue.
Either way, eat your protein and don’t fall for this protein absortion myth.
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