View Full Version : How much protein can a body handle at a time?
05-27-2004, 05:40 PM
One of my co workers said that our bodies can only process 25-30 grams of protein at a time, is this true? If not then how much protein can ones body handle? Just trying to prove him wrong!
05-27-2004, 06:09 PM
no true, i'd guess up to about 70-80g of food. you can handle more food than whey. but the 30g of whey thing is a myth. i'm sure some other people will chime in with more detailed answers, but i'm just letting you know that your co-worker is WRONG.
05-27-2004, 06:49 PM
Your body can use as much as it needs (there is no set value), whatever can't be used gets converted to glucose, and either used for energy or stored (as fat). I used to hear about the "50g rule", that about 50g was as much as you wanted to eat at one time. If you eat 8 meals a day, like I do, that would be 400g of protein a day, way more than I could possibly use. Most of my meals are around 30 grams, some more, some a little less.
05-28-2004, 04:04 AM
The body is very efficient. It will process and use all of the protein you give it. The real question is how much of this will actually go towards muscle building and how much will be converted to glucose. I would guess this would be a pretty difficult value to determine, although a value such as you have quoted does not seem unreasonable. The difference being that yes more than that will be processed but most likely not for the use you would be hoping.
05-28-2004, 05:17 AM
05-28-2004, 12:32 PM
if you drank 1 - 1.5 gallons of water, wouldnt you flush out the excess protein that would otherwise turn into fat stores?
05-28-2004, 12:44 PM
Ill probably get corrected for this but its all learning:
As far as im aware the mechanism by which water gets into the bladder is though osmotic filtering. That same filtering process will not take protein with it because the membrane through which the osmosis is occuring has holes too small for large protien chains but small enough for ionic substances and water.
Excess protien after being used for muscle synthesis and any other protien synthesis the body needs...gets converted into bodyfat. However its an inefficient process and much harder for the body to turn protien into fat than it is to turn dietary fat into bodyfat. I think though (from some distant memory) that some protien does find its way into the bladder....but that might actually be a pathology im half remebering.
Drinking lots of water (within reason) is only a good thing for you. You wont flush all the goodness out of you :) Keep it sensible (2-7 liters a day depending on needs). You can drink more but you would be Mr Toilet.
05-28-2004, 01:39 PM
well i drink 4 - 5 qts a day.
I was taught that the excess protein is distingushed through urine, and that since the body can only process x amount of protein per meal, that the excess is in danger of being stored as glucose (fat). In drinking the water, it will 1. clean out your system, sisnce your body is 70% water, thus is being essential anyway, as well as 2. flush out the unused (if I can call it that) protein that would otherwise be turned into fat.
This brings up another question, in terms of carbs, what is a reasonable number daily for bulking, is there a really difference in different carbs (since im a potato person, fries, tots, baked (never fried) this is an interest to me.
05-28-2004, 01:53 PM
I've always heard that you can't absorb more than 40g at one time. But there is no actual evidence saying how much you can or cannot absorb.
05-28-2004, 01:57 PM
It depends on the individual and the moment in time.
05-28-2004, 02:03 PM
From Maki's interview with John Berardi:
Wannabebig: With those high intakes, I wonder how much protein the body can assimilate in one sitting?
John B: 30 grams.
Wannabebig: Really? But I thought. . .
John B: Ok, ok, I'm just kidding. Got your attention though, didn't I? Actually, my real answer is this. No one's done the studies to answer this question. So we can't know for sure. What we do know is this. Protein digestion depends on a number of factors including the protein source, how the protein source was prepared, whether or not you are on any drugs that affect the GI tract, and probably a host of other factors.
Let's tackle the digestion issue first. When a food is ingested the food first must undergo the digestive process. Since the larger the meal, the slower the GI transit time, it stands to reason that most (but not all) of the protein in any given protein meal (small or large) will be digested and absorbed across the intestinal mucosa eventually. You see, the enzymes for protein digestion aren't limiting so most of the protein thrown down your gullet will be digested and absorbed if it hangs out long enough. Let me say that in another way. If you eat a meal containing 30g of protein and 95% of the protein is digested and absorbed through the intestinal mucosa, does that meal if you ate less protein, 100% would have been absorbed and if you ate more protein only 90% would be absorbed. Not at all. If you ate less protein, the time this protein sits in the GI tract would be shorter and fewer enzymes would be released so you'd probably digest and absorb 95%. And if you ate more protein, the time that this protein sits in the GI tract would be longer and more enzymes would be released so you'd probably digest and absorb about 95% of the protein. So my speculation is that digestion is more contingent upon other factors (as discussed above) than protein meal size.
To this end, Gibson and colleagues published a study in 1976 (British Journal of Nutrition) showing that an increasing protein intake did not lead to increased fecal nitrogen loss. This means that higher protein diets did not lead to more un-digested protein in the gut. These data are supported by further studies suggesting that most proteins have somewhere between 85% and 98% digestibility (meat and cheeses are around the 85-90% range while protein powders are closer to 95%). Interestingly, Pieter Evenepoel and colleagues published a nice study in the American Journal of Physiology showing that when subjects ate 25g of cooked egg protein, 93% of the protein was assimilated. However, when the eggs were not cooked, 65% of the eggs were assimilated. So it appears that food preparation is important; in the case of eggs, probably more important than meal size.
Evenpoel and colleagues also published a nice review of protein digestion and assimilation indicating, "Protein digestibility depends both on characteristics of the ingested meal and on the digestive and absorptive capacity of the upper gastrointestinal tract. The latter is significantly impaired in pancreatic disease but is also compromised by some drugs often used in clinical practice. We moreover confirmed that a substantial amount of even easily digestible dietary protein escapes assimilation in the small intestine."
So it's clear that protein type and preparation are critical to protein digestion. Unfortunately, I can't find any other studies comparing protein meals of different sizes. So the question as to how much protein can be digested in one sitting has to remain unanswered.
Beyond protein absorption through the intestinal mucosa, the protein (or, more appropriately, peptides and amino acids) must then pass through the liver en route to the blood. This is where things get can get even murkier. The liver can do a number of things with an influx of amino acids and peptides including letting them through unmolested, making glucose or glycogen out of them through deamination (gluconeogenesis), or oxidizing them. What the liver decides to do is probably dependent on the instantaneous load that it's faced with. This is probably why more protein is oxidized with a fast digesting whey than with slow digesting casein.
So, in the end, the question has to go unanswered. There's not enough data to draw definitive conclusions. Regardless, from real world experience, it's clear that weight-lifters eating even 3-4g/kg do very well. For a 100kg guy, that's an upper limit of 400g of protein. Assuming 6 - 8 meals per day, that's between 50 - 70g per meal. Assuming varied protein sources, proper preparation, and slower digesting proteins (like whole foods), at these intakes, I can't imagine any real assimilation problems.
05-28-2004, 04:50 PM
Your body can use as much as it needs (there is no set value), whatever can't be used gets converted to glucose, and either used for energy or stored (as fat).
seems the standard urban myth is 30 grams, but the intelligent answer if no set value. hell, I was getting in excess of 500 grams a day last bulk.
the other night I was watching channel 9 news, and they had a doctor on their saying that high protein causes liver damage, WTF! that was the first time I heard that one.....DOES it cause liver damage, if so, I am in trouble.
05-28-2004, 07:24 PM
The persons size has 2 b a factor, for example, i'd think that someone thats 6ft 4 would b able to process more than someone at 5ft 2
05-28-2004, 09:05 PM
In conclusion, eat all the damn protein u want, its better to be excessive than deficient.
05-29-2004, 07:31 AM
Amen to that
05-29-2004, 09:56 AM
According to my doc there is not supposed to be any protein in your urine. They actually test for that to help determine the health of your kidneys. This happened to me during a physical, she called me back in to do a retest because a test of my urine had found protein in it. A retest came back negative.
05-29-2004, 10:38 AM
hell, I was getting in excess of 500 grams a day last bulk.
Well, thats something to shoot for......
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