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Biggest protein myths debunked

getbig808

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Bodybuilding's Biggest Protein Myths DEBUNKED!
Muscular Development Online Magazine
Layne Norton, Monday, 25 September 2006

[PDF]

Bodybuilding, more so than any other sport, seems to have developed many myths that people cling to so strongly that they're accepted as FACT even though there may be little or no scientific evidence supporting these myths. Protein might possibly have more ill-founded myths surrounding it than any other subject, probably because it plays such a large role in any nutrition program focused on building muscle. Well, the myths shall spread no further: let the debunking begin!



Myth: "You can only absorb ‘X' grams of protein in one meal."

The real deal: Not only is this myth not rooted in any kind of fact, it's actually a misnomer in and of itself. Absorption refers to the amount of a certain substance that makes it into circulation (blood) from the digestive tract. The body will absorb a good portion of the protein you eat regardless of the amount of protein in the meal (though there's a limit to the percentage absorbed and it will vary between protein sources). What this myth actually refers to is protein/amino acid utilization. Specifically, what's the maximum amount of protein at a meal that will be used for muscle-building processes, and at what point does the amount of protein become excessive and the extra amino acids burned for energy rather than retained? At this point, researchers have no good answer to this question, but the answer probably depends on many various factors, including but not limited to:

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lean body mass
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length of time since last protein-containing meal
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amount of protein at previous meal
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type of protein source
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training state (Post-workout? Pre-workout? Resting?)
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total calories in the meal
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caloric balance

Although there's no definitive answer as to the maximum amount of protein that's beneficial at a meal, there's some research out there that is mildly helpful. Leucine, the amino acid that's an anabolic component of protein1 and is responsible for stimulating protein synthesis, was administered at different doses in rats to see what dose elicited the maximum protein synthetic response.2 The researchers found that the maximum beneficial dose of leucine was achieved at 0.68 grams of leucine per kilogram of bodyweight. This equates to about 62 grams of leucine in a 200-pound individual, which is an unrealistic amount to get from whole food. There are many problems with applying the absolute numbers from this study to a whole food meal in humans because of the differences in protein metabolism between rats and humans. In order to determine what level of leucine at a meal elicits the greatest anabolic response for the longest period of time more human studies will be required, but the research is moving in the right direction. While there's most definitely a maximum beneficial protein intake at a meal, no studies have directly addressed the subject and the number is likely to be influenced by various factors. So, pay no attention to Joe Dumbbell who says you can only absorb (insert gram amount) of protein at a meal, because he has no clue.



Myth: "Don't count incomplete protein sources toward your total protein intake."

The real deal: An incomplete protein source is defined as a food lacking in one or more amino acid. I believe this myth came about in response to research that concluded that when certain amino acids are deficient in the diet, skeletal muscle protein synthesis can be inhibited.3,4 This is very unlikely to be a problem for the typical bodybuilder as the condition would only manifest itself if he or she ate a diet that was predominately based on a certain food that was deficient in an amino acid over a few days, not meal to meal. Additionally, most bodybuilders consume a complete source of protein at almost every meal because any animal product will contain the complete spectrum of amino acids. Even if one consumed an incomplete protein source at a meal there's no way a decrease in protein synthesis would occur so long as a complete protein source was consumed with this meal. One should therefore absolutely count incomplete protein sources toward their total protein intake since they're consuming the full spectrum of amino acids over the range of their entire diet.



Myth: "High-protein diets are hard on the kidneys."

Quite a few medical professionals have theorized that a high-protein diet may be hard on the kidneys since a high-protein diet increases the body's production of ammonia, which must be excreted by the kidneys as urea. As a result, low-protein diets have typically been recommended to people who suffer from renal disorders. However, the notion that a high-protein diet is hard on the kidneys in a healthy person is a big stretch. Researchers who recently conducted a review of the available scientific literature on the subject concluded that "no significant evidence exists for a detrimental effect of high protein intakes on kidney function in healthy persons." 5 Additionally, a study examining bodybuilders with protein intakes of 2.8 grams per kilogram vs. well-trained athletes with moderate protein intakes revealed no significant differences in kidney function between the groups.6 It's therefore reasonable to conclude that a high-protein diet is NOT hard on the kidneys.



Myth: "Don't take your creatine with protein because protein contains glutamine and glutamine competes with creatine for the same transporter!"

The Real Deal: There's not an ounce of truth to this. Creatine and glutamine have completely different receptors. Creatine transport into skeletal muscle is regulated by the Creatine Transporter7 while glutamine transport into skeletal muscle is regulated by a system known as "System Nm." 8 The only thing these transporters have in common is that they are both sodium-dependent transporters, meaning that they use differences in sodium concentrations across the cell membrane to drive creatine into cells. Apparently somewhere along the line, somebody believed that since glutamine and creatine transporters both shared that characteristic, they must be the same transporter and the myth spread from there. Let the confusion end here: they do not share the same transporter, and taking protein/glutamine with creatine won't decrease creatine uptake into muscle.



Myth: "The more protein you take the better."


The real deal: There's little doubt that increasing one's protein intake is beneficial in achieving optimal anabolism, but some people have taken "high protein" to the extreme. Protein intakes of 2 grams per pound and even 3 grams per pound have been suggested by various trainers who believe that there's no upper limit to the anabolic effects of protein. Unfortunately, the available scientific evidence doesn't agree with their views. As protein intake increases, the body increases its production and activity of enzymes that break down and burn amino acids for energy.9,10 In fact, there's some evidence that very high protein intakes may actually decrease protein synthesis when compared to more moderate protein intakes.11 (Editor's Note: This study was conducted on endurance athletes, so it may not apply to strength-power athletes - AM.) It appears from a review of the scientific literature that there's little anabolic benefit to protein intakes over 1gram per pound of bodyweight.12,13 While on a calorie-restricted diet, increasing protein intake may have additional muscle-sparing benefits14 however, it may be wise to increase protein intake to 1.25-1.5 grams per pound of bodyweight.



Hopefully this article has helped clear up some confusion surrounding high protein diets. I fear the spread of mis-information won't end however, so it's everyone's responsibility not to be so quick to believe everything they hear or read. Keep in mind, if someone makes a claim they can't support with established scientific evidence, there's a good reason... they likely have none.



References:

  1. Norton LE, Layman DK. Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr, 2006 Feb;136(2):533S-537S.
  2. Crozier SJ, Kimball SR, Emmert SW, Anthony JC, and Jefferson LS. Oral Leucine Administration Stimulates Protein Synthesis in Rat Skeletal Muscle. J. Nutr, 135:376-382, March 2005
  3. Barnes DM, Calvert CC, and Klasing KC. Methionine deficiency decreases protein accretion and synthesis but not tRNA acylation in muscles of chicks. J Nutr, 1995 Oct;125(10):2623-30
  4. Rivera-Ferre MG, Aguilera JF, and Nieto R. Muscle fractional protein synthesis is higher in Iberian than in Landrace growing pigs fed adequate or lysine-deficient diets. J Nutr, 2005 Mar; 135(3):469-78.
  5. Martin WF, Armstrong LE, and Rodriguez NR. Dietary protein intake and renal function. Nutr Metab (Lond), 2005 Sep 20;2:25.
  6. Poortmans JR and Dellalieux O. Do regular high-protein diets have potential health risks on kidney function in athletes? Int J Sports Nutr, 2000;10:28-38.
  7. Snow RJ and Murphy RM. Creatine and the creatine transporter: a review. Mol Cell Biochem, 2001 Aug; 224(1-2):169-81.
  8. Hundal HS, Rennie MJ, and Watt PW. Characteristics of L-glutamine transport in perfused rat skeletal muscle. J Physiol, 1987 Dec;393:283-305.
  9. Block KP, Aftring RP, Mehard WB, and Buse MG. Modulation of rat skeletal muscle branched-chain alpha-keto acid dehydrogenase in vivo. Effects of dietary protein and meal consumption. J Clin Invest, 1987 May;79(5):1349-58.
  10. Boisjoyeux B, Chanez M, Azzout B, and Peret J. Comparison between starvation and consumption of a high protein diet: plasma insulin and glucagon and hepatic activities of gluconeogenic enzymes during the first 24 hours. Diabetes Metab, 1986 Feb;12(1):21-7.
  11. Bolster DR, Pikosky MA, Gaine PC, Martin W, Wolfe RR, Tipton KD, Maclean D, Maresh CM, and Rodriguez NR. Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise. Am J Physiol Endocrinol Metab, 2005 Oct;289(4):E678-83.
  12. Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci, 2004 Jan;22(1):65-79.
  13. Lemon PW. Effects of exercise on dietary protein requirements. Int J Sport Nutr, 1998 Dec;8(4):426-47.
  14. Layman DK, Evans E, Baum JI, Seyler J, Erickson DJ, Boileau RA. Dietary protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr, 2005 Aug;135(8):1903-10.
 
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nice post...already knew it tho hahah ;)

but still a good read
 
Thanks for posting that - are you the author?

Also, where's citation number 8?
 
No im not the author. It was written by Layne Norton. I posted the references so i wouldnt get yelled at again. I copy and paste. Not a good writer and a even worse speller....
 
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nice post
 
This is some good info

Where I think most fitness enthusiasts fail when it comes to protein ingestion is the quality of the protein they chose to use as fuel and building blocks

Good vs. bad

low to med heat vs. High heat cocking
Grass fed, organic, hormone and drug free vs. supermarket feed lot, injected
Rare with amino acids intact vs. over done and denatured
Real food, live with enzymes vs. dead powders and bars
Animal sources vs. non fermented soy, un sprouted legumes
 
OK, I give up.
Please, getbig808, or anyone else, answer a few simple questions for me, relating to Myth: "You can only absorb ‘X' grams of protein in one meal."

What is the generally quoted speed of absorption of whey protein, and is it regarded as a 'fast' protein? Are any other proteins absorbed faster than whey? (i.e. is chicken, beef, pork, tuna, etc. absorbed any faster?)

Which part(s) of the intestine absorb(s) the protein in a meal? What is the length of those parts?

What is peristalsis?

How long does food spend in the protein absorbing (ok, by now you know it's amino acid and di- and tri- peptide absorbing) section(s) of the small intestine?

What kind of numbers do you get when you multiply the fastest absorption rate by the number of hours food spends in the absorbing area? Does that number resemble any mythical numbers?

Are the above questions, and the answers *you found*, logical? I mean, do they make sense to you?

Oh, and that PDF you linked? Sorry, but anyone who calls it the digestive [sic] 'track' obviously hasn't been reading much. It's TRACT. And lovely reasoning like: "If our digestive systems didn't absorb most of what we eat then anytime you had a big meal you would have diarrhea like clockwork from the undigested material in the gut! "
Um, no.. if we didn't absorb most of the WATER we'd have diarrhea like clockwork. In reality, if our digestive systems didn't absorb most of what we eat, we'd have to go to the bathroom and take a s__t like clockwork... and hey, guess what! Most people *do* take a s__t like clockwork! And a whole lot of unabsorbed crap comes out! Whoever wrote that article in the PDF has the critical thinking skills of a nematode.
 
The author is Layne Norton, a lifelong natural bodybuilder and overall swell guy (I've met him) whose doctoral thesis deals with skeletal muscle protein metabolism. I did not find him to resemble - in any way - a nematode.

The article is written in the colloquial, to a broad audience, and Mr. Norton may have taken certain liberties in his lay terminology. I agree he needed an editor for that article; c'est la vie.


I shall leave your questions to people who are better educated than I.
 
This is really great information! Thank you for sharing, solved some questions for me! :)
 
The author is Layne Norton, a lifelong natural bodybuilder and overall swell guy (I've met him) whose doctoral thesis deals with skeletal muscle protein metabolism. I did not find him to resemble - in any way - a nematode.

The article is written in the colloquial, to a broad audience, and Mr. Norton may have taken certain liberties in his lay terminology. I agree he needed an editor for that article; c'est la vie.


I shall leave your questions to people who are better educated than I.

Yeah he's definitely got a great physique, and the stuff he wrote on cellular metabolism seems good, but his information in the first part of that linked PDF is way off, especially the diarrhea comment. And I'm of the opinion that words reflect the writer. I mean, would you take someone's advice if they wrote about "waitlifting"? Anyone who has studied a subject with any thoroughness should be familiar with the terminology and spelling, however his use of the word 'track' indicates to me that he's perhaps heard a lot about the digestive system, but never actually read about it. And it's not because the first page (and only the first page) is written in a dumbed-down colloquial, it's simply wrong information. The REST of the article, in which he deals with protein utilization (which he does seem to know a lot about) seems well written. However his initial premise that the 'myth' refers to protein utilization and not absorption is faulty. The 'myth' is meant to address exactly the issue that protein absorption only happens at a certain rate, and for the most part only while the bolus is in contact with the duodenum and jejunum, so eating more protein in one meal than can be absorbed in the time the food spends traveling through the jejunum is a waste. Or worse, you may think you're getting 300 grams of protein, but really only absorbing half of that if you're eating too much of your protein allotment in one sitting.
 
Yeah he's definitely got a great physique, and the stuff he wrote on cellular metabolism seems good, but his information in the first part of that linked PDF is way off, especially the diarrhea comment. And I'm of the opinion that words reflect the writer. I mean, would you take someone's advice if they wrote about "waitlifting"? Anyone who has studied a subject with any thoroughness should be familiar with the terminology and spelling, however his use of the word 'track' indicates to me that he's perhaps heard a lot about the digestive system, but never actually read about it. And it's not because the first page (and only the first page) is written in a dumbed-down colloquial, it's simply wrong information. The REST of the article, in which he deals with protein utilization (which he does seem to know a lot about) seems well written. However his initial premise that the 'myth' refers to protein utilization and not absorption is faulty. The 'myth' is meant to address exactly the issue that protein absorption only happens at a certain rate, and for the most part only while the bolus is in contact with the duodenum and jejunum, so eating more protein in one meal than can be absorbed in the time the food spends traveling through the jejunum is a waste. Or worse, you may think you're getting 300 grams of protein, but really only absorbing half of that if you're eating too much of your protein allotment in one sitting.

So how much can be absobed?
 
ThreeGigs, "track" may have been a spellcheck autopilot on Dr. Norton's part. I am a trained statistician - the word "outlier" is not a word that confuses me. But spellcheck tries to correct that word to "outliner", and if I'm not paying close enough attention when self-editing my work, that's what ends up in my final copy. I have programmed the word "outlier" into my custom dictionary, but if I use a different computer...

Alas, I have too little book larnin' to defend the rest of that PDF.

I don't know when Norton wrote it - perhaps it was early in his education? I'm sure you could contact him about it. You'd probably have a very good discussion on this topic were you to do so.
 
No im not the author. It was written by Layne Norton. I posted the references so i wouldnt get yelled at again. I copy and paste. Not a good writer and a even worse speller....

Oh there will be no more yelling! ....:paddle:
 
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where's citation number 8?


This part - the references are at the end. The citations go from 7) to 9), and seem to skip past 8)

1) Norton LE, Layman DK. Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. J Nutr, 2006 Feb;136(2):533S-537S.
2) Crozier SJ, Kimball SR, Emmert SW, Anthony JC, and Jefferson LS. Oral Leucine Administration Stimulates Protein Synthesis in Rat Skeletal Muscle. J. Nutr, 135:376-382, March 2005
3) Barnes DM, Calvert CC, and Klasing KC. Methionine deficiency decreases protein accretion and synthesis but not tRNA acylation in muscles of chicks. J Nutr, 1995 Oct;125(10):2623-30
4) Rivera-Ferre MG, Aguilera JF, and Nieto R. Muscle fractional protein synthesis is higher in Iberian than in Landrace growing pigs fed adequate or lysine-deficient diets. J Nutr, 2005 Mar; 135(3):469-78.
5) Martin WF, Armstrong LE, and Rodriguez NR. Dietary protein intake and renal function. Nutr Metab (Lond), 2005 Sep 20;2:25.
6) Poortmans JR and Dellalieux O. Do regular high-protein diets have potential health risks on kidney function in athletes? Int J Sports Nutr, 2000;10:28-38.
7) Snow RJ and Murphy RM. Creatine and the creatine transporter: a review. Mol Cell Biochem, 2001 Aug; 224(1-2):169-81.
icon_cool.gif
Hundal HS, Rennie MJ, and Watt PW. Characteristics of L-glutamine transport in perfused rat skeletal muscle. J Physiol, 1987 Dec;393:283-305.
9) Block KP, Aftring RP, Mehard WB, and Buse MG. Modulation of rat skeletal muscle branched-chain alpha-keto acid dehydrogenase in vivo. Effects of dietary protein and meal consumption. J Clin Invest, 1987 May;79(5):1349-58.

10) Boisjoyeux B, Chanez M, Azzout B, and Peret J. Comparison between starvation and consumption of a high protein diet: plasma insulin and glucagon and hepatic activities of gluconeogenic enzymes during the first 24 hours. Diabetes Metab, 1986 Feb;12(1):21-7.Bolster DR, Pikosky MA, Gaine PC, Martin W, Wolfe RR, Tipton KD, Maclean D, Maresh CM, and Rodriguez NR. Dietary protein intake impacts human skeletal muscle protein fractional synthetic rates after endurance exercise. Am J Physiol Endocrinol Metab, 2005 Oct;289(4):E678-83. Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci, 2004 Jan;22(1):65-79.
11) Lemon PW. Effects of exercise on dietary protein requirements. Int J Sport Nutr, 1998 Dec;8(4):426-47.
12) Layman DK, Evans E, Baum JI, Seyler J, Erickson DJ, Boileau RA. Dietary protein and exercise have additive effects on body composition during weight loss in adult women. J Nutr, 2005 Aug;135(8):1903-10.
 
Oh, citation 8 disappeared because the number 8 followed by a right parenthesis gets interpreted by the forum software as a smiley, and smileys are broken for some reason.

Number 8 is: Hundal HS, Rennie MJ, and Watt PW. Characteristics of L-glutamine transport in perfused rat skeletal muscle. J Physiol, 1987 Dec;393:283-305.
linkage: Characteristics of acidic, basic and neutral amino acid transport in the perfused rat hindlimb.

So how much can be absobed?

I'd rather you do the quick research yourself, but I'll answer with what I've come to believe.

Whey is noted as one of the 'fastest' proteins, meaning it gets into the blood from the intestine at one of the highest rates. That rate is widely quoted as being about 10 grams per hour.

The parts of the intestine that are responsible for 90% of protein absorption are the duodenum and jejunum. They are about 3 meters long, combined. The entire small intestine is about 7 meters long, on average.

Peristalsis is the name of the contractions that move food through the intestine.

Now, it's actually rather difficult to find a reference on the speed of peristalsis, or just how long food spends in the small intestine on its way to the colon. This site:
Intestinal Motility - Food Movement through the Small Intestine | Healthhype.com
gives a range of 3 to 5 hours. Since only roughly the first half of the small intestine absorbs protein, food would spend only 1.5 to 2.5 hours in the section that absorbs protein.

Now, you also need to know about gastric emptying, or how fast the contents of your stomach empty into the small intestine. For an 'average' meal, it's about 2 hours. Liquid meals are moved through faster, meals with a high fat content are pushed through more slowly.

So food is dumped into the small intestine for 2-ish hours, and spends another 1.5 to 2.5 hours in the absorption zone. That's about 4 and a half hours, give or take a bit. Let's round it up to 5 hours.

So (5 hours) x (10 grams/hour) = 50 grams has a chance of being absorbed before the food exits the jejunum. Any more gets delivered to the large intestine where it feeds bacteria and you wind up with protein farts. And that's 50 grams of a FAST protein.

Now, the above is based on *my* knowledge and reasoning ability. But don't believe everything you read on a forum. That's why I just posted questions that you could Google the answers to for yourself, and come to your own conclusions. But in my opinion, it's pretty clear that there is indeed a basis for the "more than 50 grams of protein in a meal is a waste" advice.

So what's the benefit of knowing all that crap, you might ask? Well, here are some guidelines I've come up with:

- Every meal should have some good protein in it. There are only 24 hours in a day, and 8 of them you're asleep. Make sure your body is given the chance to absorb as much as possible. If you follow the 'eat every 3 hours advice' I read all the time, you'll be fine.
- You should eat some whole foods, which should also contain some fat, when you drink your whey shakes. This'll slow gastric emptying, giving your intestines more time to absorb the protein. For me it's a piece of bread with 2 slices of cheese and a couple of slices of ham. Skip the bread if you're low-carbing, the cheese provides the fat.
- Speaking of 8 hours asleep, peristalsis and gastric emptying slow during sleep, but protein absorption (probably) doesn't slow much, so drink some whey before bed. I eat a small sandwich and chase it with 60 grams of whey in milk before bed.
 
Here's another, more recent article on this topic, by Alan Aragon

Is there a limit to how much protein the body can use in a single meal?
Alan Aragon, February 22nd, 2010

Introduction

A longstanding belief in fitness circles is that the body can only use a certain amount of protein per meal, and the excess is either oxidized or excreted. The ballpark range thrown around is 20-30 grams, with 30 grams being perhaps the most common figure.

This guideline has led many trainees to go through the pains of consuming multiple doses of protein throughout the day, banking that it will maximize muscle anabolism or muscle retention.

Well, true or not, this concept fits in nicely with another longstanding fitness “rule” that you have to eat at least six times per day in order to keep the body’s metabolism revving high. Since the meal frequency and metabolism dogma has been thoroughly debunked [1-5], it’s time to dig into the topic of whether there’s a limit to effective protein dosing, and if so, what that limit might be.

Looking at simple logic first

Let’s imagine an experiment involving two relatively lean 200 lb individuals. For the purposes of this illustration, I’ll assign a daily amount of protein known to adequately support the needs of the athletic population. We’ll give Person A 150 g protein spread over five meals at 30 g each. We’ll give Person B the same amount of protein, but in a single meal. Let’s say that this meal consists of a 16 oz steak, chased with a shake containing two scoops of protein powder.

If we really believed that only 30 g protein can be handled by the body in a single meal, then Person B would eventually run into protein deficiency symptoms because he supposedly is only absorbing a total of 30 g out of the 150 g we’re giving him. At 30 g/day, he’s only getting 0.33 g/kg of bodyweight, which isn’t even half of the already-low RDA of 0.8 g/kg. If the body worked this way, the human species would have quickly become extinct. The human body is more efficient and effective than we give it credit for.

The body will take all the sweet time it needs to effectively digest and absorb just about whatever dose you give it. Person A will have shorter digestion periods per meal in order to effectively absorb and utilize the small meals. Person B will have a longer digestion period in order to effectively absorb and utilize the large meal. While the truth in this logic seems self-evident, the important question is whether or not it’s supported by scientific research. Let’s look at the evidence, starting with immediate-effect (acute) studies, then move on to the longer-term trials.

Research examining speed of absorption

A thorough literature review by Bilsborough and Mann compiled data from studies by various investigators who measured the absorption rates of various protein sources [6]. Oddly, an amino acid mixture designed to mimic the composition of pork tenderloin made the top spot, at 10 g/hour, while whey took a close second at 8-10 g/hour. Other proteins fell in their respective spots below the top two, with little rhyme or reason behind the outcomes. As a matter of trivia, raw egg protein was the most slowly absorbed of them all at 1.3 g/hour.

It’s important to note that these data have some serious limitations. A major one is the variance of the methods used to determine the absorption rates (i.e., intravenous infusion, oral ingestion, ileal ingestion). Most of the methods are just too crude or far-fetched for serious consideration. Another limitation is that these figures could be skewed depending upon their concentration in solution, which can affect their rate of gastric evacuation. Another factor to consider is the timing of ingestion relative to exercise and how that might differentially affect absorption rates. Finally, short-term data leaves a lot open to question.

Short-term research supporting the magic limit

I’ve heard many folks parrot that the maximal anabolic effect of a single protein dose is limited to 20 grams, citing recent work by Moore and colleagues [7]. In this study’s 4-hour post-exercise test period, 40 g protein did not elicit a greater anabolic response than 20 g. I’d interpret these outcomes with caution. Fundamentally speaking, protein utilization can differ according to muscle mass. The requirements of a 140-lb person will differ markedly from someone who’s a lean 200. Additionally, a relatively low amount of total volume was used (12 sets total). Typical training bouts usually involve more than one muscle group and are commonly at least double that volume, which can potentially increase the demand for nutrient uptake. Finally, the conclusion of the authors is questionable. They state explicitly,

“…we speculate that no more than 5-6 times daily could one ingest this amount (~20 g) of protein and expect muscle protein synthesis to be maximally stimulated.”

So, they’re implying that 100-120 grams of protein per day is maximal for promoting muscle growth. Wait a minute, what? Based on both the bulk of the research evidence and numerous field observations, this is simply false [8,9].

In another recent study, Symons and colleagues compared the 5-hour response of a moderate serving of lean beef containing 30 g protein with a large serving containing 90 g protein [10]. The smaller serving increased protein synthesis by approximately 50%, and the larger serving caused no further increase in protein synthesis, despite being triple the dose. The researchers concluded that the ingestion of more than 30 g protein in a single meal does not further enhance muscle protein synthesis. While their conclusion indeed supports the outcomes of their short-term study, it’s pretty easy to predict the outcomes in muscle size and strength if we compared a total daily protein dose of 90 g with 30 g over a longer trial period, let alone one involving a structured exercise protocol. This brings me to the crucial point that acute outcomes merely provide grounds for hypothesis. It’s not completely meaningless, but it’s far from conclusive without examining the long-term effects.

Longer-term research challenging the magic limit

If we were to believe the premise that a 20-30 g dose of protein yields a maximal anabolic effect, then it follows that any excess beyond this dose would be wasted. On the contrary, the body is smarter than that. In a 14-day trial, Arnal and colleagues found no difference in fat-free mass or nitrogen retention between consuming 79% of the day’s protein needs (roughly 54 g) in one meal, versus the same amount spread across four meals [11].

Notably, this study was done on young female adults whose fat-free mass averaged 40.8 kg (89.8 lb). Considering that most non-sedentary males have considerably more lean mass than the female subjects used in the aforementioned trial, it’s plausible that much more than 54 g protein in a single meal can be efficiently processed for anabolic and/or anti-catabolic purposes. If we extrapolated the protein dose used in this study (79% of 1.67g/kg) to the average adult male, it would be roughly 85-95 g or even more, depending on just how close someone is to the end of the upper limits of muscular size.

When Arnal and colleagues applied the same protocol to the elderly population, the single-dose treatment actually caused better muscle protein retention than the multiple-dose treatment [12]. This raises the possibility that as we age, larger protein feedings might be necessary to achieve the same effect on protein retention as lesser amounts in our youth.

IF research nailing the coffin shut?

AtLarge Nutrition Nitrean - Award Winning Protein
Perhaps the strongest case against the idea of a dosing limit beyond which anabolism or muscle retention can occur is the recent intermittent fasting (IF) research, particularly the trials with a control group on a conventional diet. For example, Soeters and colleagues compared two weeks of IF involving 20-hour fasting cycles with a conventional diet [13]. Despite the IF group’s consumption of an average of 101 g protein in a 4-hour window, there was no difference in preservation of lean mass and muscle protein between groups.

In another example, Stote and colleagues actually reported an improvement in body composition (including an increase in lean mass) after 8 weeks in the IF group consuming one meal per day, where roughly 86 g protein was ingested in a 4-hour window [14]. Interestingly, the conventional group consuming three meals spread throughout the day showed no significant body composition improvements.

Keep in mind that bioelectrical impedance (BIA) was used to determine body composition, so these outcomes should be viewed with caution. I’ve been highly critical of this study in the past, and I still am. Nevertheless, it cannot be completely written off and must be factored into the body of evidence against the idea of a magic protein dose limit.

Conclusion & application

Based on the available evidence, it’s false to assume that the body can only use a certain amount of protein per meal. Studies examining short-term effects have provided hints towards what might be an optimal protein dose for maximizing anabolism, but trials drawn out over longer periods haven’t supported this idea. So, is there a limit to how much protein per meal can be effectively used? Yes there is, but this limit is likely similar to the amount that’s maximally effective in an entire day. What’s the most protein that the body can effectively use in an entire day? The short answer is, a lot more than 20-30 g. The long answer is, it depends on several factors. In most cases it’s not too far from a gram per pound in drug-free trainees, given that adequate total calories are provided [8,9].

In terms of application, I’ve consistently observed the effectiveness of having approximately a quarter of your target bodyweight in both the pre- and post-exercise meal. Note: target bodyweight is a surrogate index of lean mass, and I use that to avoid making skewed calculations in cases where individuals are markedly over- or underweight. This dose surpasses the amounts seen to cause a maximal anabolic response but doesn’t impinge upon the rest of the day’s protein allotment, which can be distributed as desired. On days off from training, combine or split up your total protein allotment according to your personal preference and digestive tolerance. I realize that freedom and flexibility are uncommon terms in physique culture, but maybe it’s time for a paradigm shift.

In sum, view all information – especially gym folklore and short-term research – with caution. Don’t buy into the myth that protein won’t get used efficiently unless it’s dosed sparingly throughout the day. Hopefully, future research will definitively answer how different dosing schemes with various protein types affect relevant endpoints such as size and strength. In the mean time, feel free to eat the whole steak and drink the whole shake, and if you want to get the best bang for your buck, go for a quality protein blend such as Nitrean! ;)


About Alan Aragon

Alan Aragon has over 15 years of success in the fitness field. He earned his Bachelor and Master of Science in Nutrition with top honors. Alan is a continuing education provider for the Commission on Dietetic Registration, National Academy of Sports Medicine, American Council on Exercise, and National Strength & Conditioning Association. Alan recently lectured to clinicians at the FDA and the annual conference of the Los Angeles Dietetic Association.

He maintains a private practice designing programs for recreational, Olympic, and professional athletes, including the Los Angeles Lakers, Los Angeles Kings, and Anaheim Mighty Ducks. Alan is a contributing editor and Weight Loss Coach of Men’s Health magazine.

His book Girth Control is considered one of the most in-depth manuals for physique improvement and understanding nutrition for fitness & sports. Last but not least, Alan writes a monthly research review providing of the latest science on nutrition, training, and supplementation. Visit Alan’s blog to keep up with his latest shenanigans.

References

1. Smeets AJ, Westerterp-Plantenga MS. Acute effects on metabolism and appetite profile of one meal difference in the lower range of meal frequency. Br J Nutr. 2008 Jun;99(6):1316-21.

2. Taylor MA, Garrow JS. Compared with nibbling, neither gorging nor a morning fast affect short-term energy balance in obese patients in a chamber calorimeter. Int J Obes Relat Metab Disord. 2001 Apr;25(4):519-28.

3. Bellisle F, McDevitt R, Prentice AM. Meal frequency and energy balance. Br J Nutr. 1997 Apr;77 Suppl 1:S57-70.

4. Verboeket-van de Venne WP, Westerterp KR. Frequency of feeding, weight reduction and energy metabolism. Int J Obes Relat Metab Disord. 1993 Jan;17(1):31-6.

5. Verboeket-van de Venne WP, Westerterp KR. Influence of the feeding frequency on nutrient utilization in man: consequences for energy metabolism. Eur J Clin Nutr. 1991 Mar;45(3):161-9.

6. Bilsborough S, Mann N. A review of issues of dietary protein intake in humans. Int J Sport Nutr Exerc Metab. 2006 Apr;16(2):129-52.

7. Moore DR, et al. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. Am J Clin Nutr. 2009 Jan;89(1):161-8.

8. Campbell B, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2007 Sep 26;4:8.

9. Tipton KD, Wolfe RR. Protein and amino acids for athletes. J Sports Sci. 2004 Jan;22(1):65-79.

10. Symons TB, et al. A moderate serving of high-quality protein maximally stimulates skeletal muscle protein synthesis in young and elderly subjects. J Am Diet Assoc. 2009 Sep;109(9):1582-6.

11. Arnal MA, et al. Protein feeding pattern does not affect protein retention in young women. J Nutr. 2000 Jul;130(7):1700-4.

12. Arnal MA, et al. Protein pulse feeding improves protein retention in elderly women. Am J Clin Nutr. 1999 Jun;69(6):1202-8.

13. Soeters MR, et al. Intermittent fasting does not affect whole-body glucose, lipid, or protein metabolism. Am J Clin Nutr. 2009 Nov;90(5):1244-51.

14. Stote KS, et al. A controlled trial of reduced meal frequency without caloric restriction in healthy, normal-weight, middle-aged adults. Am J Clin Nutr. 2007 Apr;85(4):981-8.
 
It's a lovely little paper, but the problem I had with it is that he flip-flops between utilization and absorption. He never addressed absorption except here:

"If we really believed that only 30 g protein can be handled by the body in a single meal, then Person B would eventually run into protein deficiency symptoms because he supposedly is only absorbing a total of 30 g out of the 150 g we’re giving him. At 30 g/day, he’s only getting 0.33 g/kg of bodyweight, which isn’t even half of the already-low RDA of 0.8 g/kg. If the body worked this way, the human species would have quickly become extinct. The human body is more efficient and effective than we give it credit for."

There. Is. No. Justification. Why would the human species have become extinct? Is he saying that throughout history, man has only ever consumed one meal per day, until modern times? He doesn't explain WHY we would have died out. And since his "thought experiment" is based on "relatively lean 200 lb individuals" , are we to assume that the bulk of breeding humans throughout history were 200 pound women and men with very low bodyfat? I smell a strawman. Oddly enough, the 'magic number' my logic above produced was roughly 50 grams of protein *absorbed* in an average meal (assuming meat protein is 10 grams/hour), which just happens to be really close to the RDA for an *average* male these days.

Other proteins fell in their respective spots below the top two, with little rhyme or reason behind the outcomes. As a matter of trivia, raw egg protein was the most slowly absorbed of them all at 1.3 g/hour.
Whoa. Little rhyme or reason? Now c'mon. Trypsin and other proteases break protein down into peptides. Trypsin works by cleaving proteins at a lysine or arginine bond, other proteases cleave at different points. The first part of the small intestine has cells called enterocytes which are specialized absorbers. Some absorb only single amino acid molecules, some absorb di- and tri- peptides (2 or 3 aminos chained together). There is virtually NO absorption of chains of 4 or more peptides. Now, if a protein is 'conveniently' constructed, such that when the proteases act on it it gets broken down to 1, 2 and 3 amino-unit sections without much further processing needed (and doesn't need a protease which the body produces little of to break down further), it will be absorbed with good efficiency, and speed. All one really needs to know to get a general idea of whether a protein will be 'fast' or 'slow', and whether it'll be faster or slower than other proteins, is the order of amino acids in the protein, the folded structure or the protein, and which proteases (i.e. human, rat, etc.) will be acting on it. It's not an exact science because of the way proteins are folded, however it's a far cry from "little rhyme or reason".

Oh, and the reason RAW egg WHITE protein (albumen) was the slowest at 1.3 grams an hour? Because raw egg whites contain ovomucoids, which are trypsin inhibitors (I've posted in these forums about raw egg whites before). Inhibit trypsin and the proteins don't get broken down into units small enough to be absorbed.

After that he goes into utilization. Now, the purported 'myth' isn't about utilization, it's about absorption, so any utilization arguments are a sidetrack. Granted, they *are* relevant to an overall discussion on protein dose and timing concerns, but that's not what I'm trying to address about the 'myth debunking'.

Oh, and I wish the guy would make up his mind about how much is enough.

He says:
So, they’re implying that 100-120 grams of protein per day is maximal for promoting muscle growth. Wait a minute, what? Based on both the bulk of the research evidence and numerous field observations, this is simply false [8,9].

So he's saying 120 grams of protein a day isn't enough.
But then he also says:
Perhaps the strongest case against the idea of a dosing limit beyond which anabolism or muscle retention can occur is the recent intermittent fasting (IF) research, particularly the trials with a control group on a conventional diet. For example, Soeters and colleagues compared two weeks of IF involving 20-hour fasting cycles with a conventional diet [13]. Despite the IF group’s consumption of an average of 101 g protein in a 4-hour window, there was no difference in preservation of lean mass and muscle protein between groups.

In another example, Stote and colleagues actually reported an improvement in body composition (including an increase in lean mass) after 8 weeks in the IF group consuming one meal per day, where roughly 86 g protein was ingested in a 4-hour window [14].

So what the heck, 120 grams isn't enough, but 86 grams is fine? Okay, I'll grant that what probably went unsaid was that individuals who exercise on a regular basis will need more than the RDA. But oddly enough, NEITHER of the sources he cited justifies more than 120 grams. The first one, [8], is a position statement that says, in a nutshell: "2 grams per kilo of bodyweight won't hurt, and might help if you're an olympic caliber athlete, so that's what we're recommending." And his second citation, [9], even contains this little gem which is the opposite of his argument: "However, there are few convincing outcome data to indicate that the ingestion of a high amount of protein (2-3 g x kg(-1) BW x day(-1), where BW = body weight) is necessary."

Oh, here's another little gem:
In another recent study, Symons and colleagues compared the 5-hour response of a moderate serving of lean beef containing 30 g protein with a large serving containing 90 g protein [10]. The smaller serving increased protein synthesis by approximately 50%, and the larger serving caused no further increase in protein synthesis, despite being triple the dose. The researchers concluded that the ingestion of more than 30 g protein in a single meal does not further enhance muscle protein synthesis. While their conclusion indeed supports the outcomes of their short-term study, it’s pretty easy to predict the outcomes in muscle size and strength if we compared a total daily protein dose of 90 g with 30 g over a longer trial period, let alone one involving a structured exercise protocol. This brings me to the crucial point that acute outcomes merely provide grounds for hypothesis. It’s not completely meaningless, but it’s far from conclusive without examining the long-term effects.
The bolding is mine. He takes a study of a single meal over a 5-hour timeframe and then somehow interprets it as a TOTAL DAILY protein intake. What, people can't eat more than once a day with this guy? Does the author have some sort of agenda regarding promoting protein supplementation? I mean, it's not like he made a recommendation for a particular brand or anything.....is it?
 
ThreeGigs, thank you so much for your incredibly well-informed contributions to this thread.

My interest in protein comes from a completely unrelated direction: I use it to kill hunger, and nothing suppresses ghrelin longer than a large meal of mostly protein. Some protein sources seem to perform this function better than others.

In light of this, I'm very interested these proteases and enterocytes. Do you have a link where I could read more on this topic - it's really fascinating to me.
 
I usually start all my research on Wikipedia, then use the keywords I find in the articles to do Google searches. Quite often I hit upon a Google Books result, and I can get some more info from a book excerpt. For example:
Frontiers in eating and weight ... - Wolfgang Langhans, Nori Geary - Google Books
On rare occasions, I can find .. a...um... torrent of information *cough* in the form of college textbooks. Here in Poland I can't exactly run down to the local college's used bookstore and find a biology/medical/nutrition book in English, but that might be a good source of info for you too.

I use a few tricks to get the most out of Google results. If you're looking for studies, always include the word "abstract" in your query. Many times Google offers a "scholarly results" link which can be a goldmine of info, or a deep morass of technical mumbo jumbo, your mileage may vary. Use the advanced search functions on Google to narrow your results. Oh, and many times if I find some research for which only the abstract is available on the NIH website, I put part of the abstract in quotes and search for it. It's how I can sometimes find the whole study.



So for example, I check out Wikipedia for protein. And then digestion. And if you search Wikipedia for 'protein degradation', you get redirected to the proteolysis article. The proteolysis article has links to things like catabolism, and some of the common proteases.

Check out the references at the bottom of the articles, and look for more keywords to do Google searches on. I generally get sidetracked every time I explore any information about protein, it's just so damned complicated. And oddly enough, *you* were the stimulus that got me started on studying human nutrition and digestion, because you are a veritable treasure trove of knowledge when it comes to diet. Something you wrote impressed upon me just how friggin' hard it was going to be to do a recomp *right* and be able to gain muscle and lose fat at the same time.

And let me tell you, there are some really, REALLY cool things to be found in studies.
"A limit on the energy transfer rate from the human fat store in hypophagia" was an absolute godsend for giving me good, hard numbers and insight on how to lose fat as fast as possible and still gain muscle.
"A Review of Issues of Dietary Protein Intake in Humans" by Shane Bilsborough and Neil Mann is a nice meta-study plus some original research, and was the article that made me understand the relationship between protein and kidney function. It also made me find the definition of "biological stress", which made me understand that while excess protein stresses the kidneys (makes 'em work harder), it doesn't damage them unless they're already failing. But since excess urea in the blood (hey, it's gotta be somewhere before the kidneys filter it out) is undesirable and detrimental to a few body processes most athletes would consider important, I was again pushed to research protein dosage so that I could eat a little more than optimum, but not so much as to have higher blood urea levels interfering with anabolic processes.

Oh, and "Observations of Branched-Chain Amino Acid Administration in Humans" by Dwight E. Matthews is a good read.

Somewhere, in a study I can't find at the moment, there was buried in the middle of it an interesting observation which I found invaluable. Basically, it said that protein synthesis is only increased when there is a change in blood amino acid concentration. If the concentration stays level, even a high level, nothing special happens. That bit of insight led me to my current thinking which is protein has to be 'pulsed', as in I believe there MUST be a minimum time allowed between meals to allow AA levels in the blood to fall before eating again. I *think* it's because of insulin induced AA uptake by the muscles, but I'm still reading up on insulin (ugh).

So um yeah. Just Google everything, even if it does't appear immediately related, because it might affect a thing which affects a thing which has something to do with protein and could be important or offer some insight.
 
Thanks for that. I was thinking you might have taken some courses in physiology that explained specifically about proteases and enterocytes. Do you have formal training in these areas?
 
I usually start all my research on Wikipedia, then use the keywords I find in the articles to do Google searches. Quite often I hit upon a Google Books result, and I can get some more info from a book excerpt. For example:
Frontiers in eating and weight ... - Wolfgang Langhans, Nori Geary - Google Books
On rare occasions, I can find .. a...um... torrent of information *cough* in the form of college textbooks. Here in Poland I can't exactly run down to the local college's used bookstore and find a biology/medical/nutrition book in English, but that might be a good source of info for you too.


On a side note ive been trying to find more information on wnt7a protein stmulator or something like it and im having a hard time. You might be able to help???? Just a thought...
 
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