How Much Protein Can You Absorb In One Meal?
For anyone looking to build muscle, improve recovery or lose a little fat protein is a very popular topic. Whether it’s a case of wondering how much to get in across a day or what the best source of protein is, there is a lot to unpack when it comes to this macronutrient. One question I commonly get asked with regards to protein is “How much protein can you absorb in one meal?”. In this blog we’re going to dive into exactly that.
We’ll look at what the research says with regards to portion sizes to optimise muscle protein synthesis and have a deep dive into a new paper that may shine some light on the fact we may be able to absorb more than we think. So grab yourself a protein shake, gnaw on some chicken breast and get ready to read all the answers!
What Does The Science Say About Protein Absorption?
For decades now, the standard advice when it comes to protein and muscle building has been to consume 2 grams of protein per kilo bodyweight per day and to split this into 3-5 servings of around 20-40g. This idea came from early studies that measured muscle protein synthesis (MPS) in response to a protein feed. The thinking being that protein feeds stimulate MPS, so more feeds across the day means more MPS and less muscle protein breakdown as shown by the graph below.
The Leucine Threshold: A Key Player in Muscle Protein Synthesis
These portion sizes of 20-40g have also been linked with the “leucine threshold”. Leucine is an amino acid that plays a crucial role in muscle protein synthesis. The leucine threshold is a theory that a certain amount of leucine has to be consumed in a feed for muscle protein synthesis to occur, it essentially acts like an “on switch” for muscle growth. For most protein sources this threshold would be hit at 20g or more of the protein, hence why this number is recommended as opposed to significantly more smaller feeds.
Emerging Research, More Protein May Be Better
A recent study re-examined the idea of protein absorption and looked at the impact varying protein feeds had on markers of anabolism. What was novel about this study was they looked at single feeds of up to 100g of protein per serving! The aimed to see whether there is a limit to the anabolic response after exercise and used isotope tracers to monitor protein synthesis rates.
The results showed that there was a continuous increase in markers of MPS with higher protein doses, with these markers staying elevated for longer in the upper limit of 100g. This tells us that there may not be an upper limit with regards to protein feeds and more may indeed be better per serving!
But this is just one study in a sea of so many, it’s very interesting and means that it may not be the worst thing in the world if you have fewer servings but larger size, the main thing when it comes to protein is likely still getting enough in across the course of the day.
Practical Applications: How Much Protein Should You Eat in One Meal?
As stated above, although there’s some really interesting results from this study, I’m personally still recommending most athletes to take on 3-5 servings of 20-40g of protein across the day. That being said, with the athletes I work with in strength sports and CrossFit and with a few athletes of a larger bodyweight the serving sizes are actually heading above this for certain meals. The main reason for this though is to ultimately be able to hit their protein needs across the day.
With the emerging research from the study we mentioned above, we can essentially be a little more loose with the upper limit of protein servings. We should still aim to consume enough to break the leucine threshold, and I believe we should still be having 3-5 servings/day to maximise muscle protein synthesis, but if one or two of those servings, say the one post exercise and perhaps dinner, are larger than 40g then it’s not really going to be an issue and may even be beneficial.
The main thing as always is getting enough in across the day. If you want a deeper insight into protein and training it’s always worth checking out the ISSN’s position stand on the subject here.
But with regards to the question of “How much protein can you absorb in one meal?” the actual answer with the emerging research seems to be, we’re still not sure but it may be more than we thought!
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