One of the more common questions that many gym enthusiasts bring up is “How much protein can the body digest at one time?”
For some odd reason this purported, arbitrary amount of protein seems to land somewhere between 30-50g for all humans, regardless of body mass.
If that supposition isn’t already asinine enough, allow me to elucidate you about why the body can handle quite a bit more protein in one sitting then people seem to give it credit for.
Early phases of protein digestion
Before we dabble in protein quantities and tangible figures for you to implement, it’s worthwhile to have a rudimentary understanding of how protein is actually metabolized by the human body. Granted the entire scope of protein digestion is a field of research in and of itself, we will still go over the gist of how it works.
Firstly, as you likely already know, the ingestion process begins in the mouth which is primarily responsible for the physical breaking down of foods. After you’re incisors and molars do their dirty work, the broken bits of food/nutrients (in this instance, protein) make their way to the stomach where the digestion process kicks in.
The stomach is a rich source of gastric juice, which is composed of hydrochloric acid, sodium chloride and potassium chloride. These acids initiate the chemical breakdown (denaturation) of proteins and activate the necessary digestive enzymes to further the process of digestion. One of the key enzymes in protein digestion is pepsin, which is why some naturopaths assert that those who eat a large amount of protein should supplement with this enzyme, but that remains to be investigated for efficacy.
Late phases of protein digestion
Moving on, after the protein has been denatured sufficiently; the eluting polypeptides make their way to the duodenum, which is the anterior segment of the small intestine. The duodenum is the site of the majority of protein digestion and amino acid absorption. The plethora of digestive enzymes present in the small intestine serves to further cleave the polypeptides into isolated amino acids and minute amounts of di-/tri-peptides.
Towards the end of protein digestion, the isolated amino acids are destined to either entrance of the intestinal cells or passing through circulation towards the liver. Once in the liver, amino acids are finally subject to the proper metabolic pathways in accordance with the body’s energetic requirements (e.g. utilized for protein synthesis, used as a substrate for gluconeogenesis, etc.)
So how much protein can the human body really digest in one sitting?
With the basics of protein digestion covered, let’s take a pragmatic look at the theories and research behind how much protein can be digested at a given time. It should be noted here that this question is asking about how much can be digested, which isn’t the same as asking how much can be used for muscle protein synthesis (MPS); digestion and MPS aren’t interchangeable terms like some people seem to believe.
Back on topic, the idea that the human body has a rather random “protein cap” at the 30-50g mark just doesn’t hold up from an evolutionary nor biochemical aspect. Essentially, the supposition that your body doesn’t (read: can’t) absorb/digest more than 30g-50g of protein at once is inherently suggesting that you are just excreting any amount of protein over that mark in your feces.
So in essence, instead of your body digesting the “excess” protein, it magically bypasses the highly conserved/intricate digestive process that we covered in this article and sends the extra protein to your colon. Hmmm…we’d be pretty screwed from a physiological standpoint if that were true, not to mention people would be living on the toilet.
Moreover, there is little-to-no literature that confirms the body doesn’t absorb more than 30-50g of protein at a given moment. In fact, the literature supports that the body can indeed digest quite a large bolus; it just takes longer than a smaller dose.[1]
Basically, rather than just redirecting excess protein to your colon, the rate of digestion compensates to reduce the supply of nutrients being sent to the anterior small intestine (i.e. the stomach delays gastric processes).
For the absolute extremists who like to propose rather absurd circumstances, like eating 200g of protein at once, would the body be able to digest all of it? Well frankly, yes, but not all of that will be put to “good use” so to speak.
Protein can indeed be converted to fat, but the pathways to do so are inefficient biochemically so the significance of this conversion is trivial. Most likely, the majority of protein that isn’t used for MPS or other anabolic processes is probably subject to hepatic gluconeogenesis and subsequently stored in the form of glycogen.
So there you have it, you can eat quite a bit of protein at any given time, just don’t be too extreme about it if you want to effectively utilize the amino acids.
References:
1. Adibi, S. A., & Mercer, D. W. (1973). Protein digestion in human intestine as reflected in luminal, mucosal, and plasma amino acid concentrations after meals. Journal of Clinical Investigation, 52(7), 1586.
30 Comments
A lot of angry people on here. You guys need to get off the gas.
Now, too much protein and gluconeogenesis takes place, converting the excess protein into glucose. What isn't used is stored as fat.
Muito boa essa informação , No Brasil não temos tanta informação e com tanta qualidade , excelente site continuem assim .
This entire article was based on research from 1973? Ill continue to get my info from guys that base their conclusions off of modern research...like Dr. Mike Israetel, and Dr. Layne Norton.
I thought the article was relevant and certainly became a source of mostly good conversation. It's disappointing that some individuals responding to the article are so rude and obtuse Iin their responses. I would've liked to have seen more recent references used ... nothing older than 10 years. The field of Exercise Science has integrated the fields of Neurobiology, Chemistry, Biochemistry, Nutrition, Biology, Micobiology, Cytology, etc. Information from three or four peer reviewed journal articles from the past 5 -10 years would have made would have your article solid.
Your source was from 1973! We've learned a lot since then. I would do A LOT more research before posting an article on the internet that runs against the grain of modern research.
You should educate your fellow author then:
https://www.muscleandstrength.com/articles/how-much-protein-need
Who writes:
"The average person cannot absorb more than 20 grams of protein at a time. This means, eating multiple meals per day is necessary. Is that a pain? Yes!"
This is why there is confusion out there...
-AJ
I really don't know where did some of you read that more than 50grams would be wasted.. He's been saying the opposite, read it again and try to understand first.
protein is good. while training for the Army Marathon I found that my recovery from long runs was quicker when I increased my protein intake daily. The most notable thing i did was to have whey immediately after waking up.
EAT THE F*****G PROTEIN!
30-50g of protein only irrespective of the source is it? Suppose if I take two scoops of whey protein after workout and after 30 min of i take protien rich dinner, then according to this article most of the protien will go wasted is it?
I'm honestly baffled where you drew this conclusion from AFTER READING THE ARTICLE...
I feel so sorry for you Elliot. This article was rock solid and explained everything in enough detail without going into advanced biochemical actions which *clearly* these people wouldn't understand. Some people just can't be helped my friend..
I have been playing around with digestion of Protein for over 25 years now. I had found that exactly 50 grams of good Whey Protein drink does nothing but bypass through me (without eating anything). If I take 50 grams of protein with food, it seems to "stick" better. If I take 30 grams of protein on an empty stomach, I am perfectly fine with the absorption. Anything more then that on an empty stomach yields the same results as 50 grams. So, I suggest you just experiment in maybe 5 gram increments and find out what your tolerance is so you don't end up wasting your money down the toilet. I only wish I had experimented like this when I was younger. Anyway, that's my input, hope it helps out ~ Ken
... I'm frightened to ask but what method did you use to figure out that all 50 Grams passed right through you?
What method? LOL Quite easy when you're literally running to the bathroom after 30 Grams. I tried 50 originally because I had ready years ago that your body could absorb the 50 grams. Again, when I adjusted my intake, I was just fine. Also, not sure if I mentioned this but when I said taking protein in large amounts, it was just from a protein shake, not solid food. If I eat a good heaping amount of protein packed food, I seem to be ok.
I think that what this article is missing is the effect it has on the renal system. The kidneys cannot handle such large amounts of protein passing through every day...
That's a myth. Healthy functioning kidneys will have no issues with the the amount of protein intake naturals require to build muscle.
This myth has been proven incorrect ad nauseum.
For a lot of people this is their research, not all of us want to take a class and become nutritionists, chemists, or biologists, so the fact that the person posting this article says a lot without really answering the question is insulting to everyone reading it. So what your saying is we can digest all the protein that comes in our bodies....yeah, anything we eat or drink HAS to go through the digestive process, I get that, I learned it in High School, but what people really want to know is if the body is going to absorb and use it all for muscle building. The person brushed on this by saying excess protein will be converted to other things, so basically the answer is NO if you consume 100s of grams of protein a day it will not make your muscles recover quicker or build themselves up stronger just because you are taking in more protein, because there will be excess. What he doesn't specify is what is an average amount that is optimal for muscle growth and recovery so that I have little to no excess to be turned into other things. One study I read online was posted by a University in Canada and said that 56-77% of body weight in grams per day was optimal for recovery and growth, that Olympic athletes do well with the 77%....basically if I weighed 100 pounds that I should take in 77 grams of protein a day for muscle growth and recovery with little excess to be stored in other forms or passed. I've also heard on the Bodybuilding.com forums that it's anywhere between 100-150% of body weight in grams per day....but I've also heard of ludicrous amounts such as 500%, but I seriously doubt if I'm stuffing that much protein into my stomach I'd have the appetite for anything else and would probably just make myself sick. I'm going with the 77% at the moment....my workout routine is P90X or Insanity in the mornings with heavy lifting in the afternoon evenings and Army PT (including 10 mile runs, 12 mile rucks, and standard PT test) somewhere in the middle 5-6 days a week with one day of doing nothing rest. So far it's worked out well and I've lost fat at a steady rate.
I still don't understand why people keep insisting that I "didn't answer the question". Did you read the article?
"What he doesn't specify is what is an average amount that is optimal for muscle growth and recovery so that I have little to no excess to be turned into other things..." I didn't cover this because I've already written quite a bit about that topic elsewhere: https://www.muscleandstrength.com/articles/vary-protein-sources-muscle-b...
Who knows if this is true or not. By default I never believe the guy trying to sell me something.
Muscle and Strength is a website, not a lab you jerks. Do your own research
Then they should not write articles and dispute claims with no lab findings to back up their inferences!
Dude seriously stop telling people excess macronutrients will lead to fat gain. if my diet consist of 2500 calories to lose fat and I consume that all in protein I will still lose fat ya idiot its all about calories in vs calories out
Protein can indeed be converted to fat, but the pathways to do so are inefficient biochemically so the significance of this conversion is trivial. Most likely, the majority of protein that isn’t used for MPS or other anabolic processes is probably subject to hepatic gluconeogenesis and subsequently stored in the form of glycogen.
hmmm so if I eat 400g of protein I will get fat? umm idt so excess calories is the only way to get fat
400 grams of protein would be the equivalent to 1600 calories and that's assuming that there is only protein involved, and no carbs or fat. So yes, with the average diet along side 400g of protein, you would get fat. The nutritional facts conversion chart goes as such: 1g Fat=9 calories, 1g Carb=4 calories, 1g protein=4 calories. So if you were consuming 3000 calories from carbs and fat in a day, and 400 grams of protein (1600 calories), you would get fat depending on your metabolism and how active you are.
i read your article and yet still unsatisfied. so what can you say about people who use Interminent fasting, eating 100g+ protein in one sitting but still having a good gains?
Dude just say YES or NO! Your article is really pointless you could end this topic with a YES or a NO answering if you can digest more than 50 grams of protein in one sitting. and if you say that not all of the 50 grams will be absorbed, you can actually tell us how much in the 50 grams will be absorbed and how much will be wasted!
you obviously didn't read the article, yes your body can digest 50 grams of protein, it could digest 200 grams of protein. But an excessive amount will lead to the storing of protein in ways you did not intend. Technically you just digested 200 grams of protein but just because it is digested does it mean the amino acids did what you want them to. If you ate an entire pie would your body just not be able to digest the amount of sugar you ate and explode? no, the carbohydrates just wouldn't be used for what you intended them to be used for and be stored as fat. Plus the question is how much can you digest, that is not a yes or no question obviously.
So if i consume a protein shake consisting of 96 grams of protein, would that be okay and would it turn to fat?
You clearly didn't even read the f***ing article...