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This is essentially the crux of the "protein requirements for athletes" colloquium at ACSM this year. I will disclaim this by saying that I have not evaluated the evidence myself yet, and so am just reporting what was said at the colloquium--not that I have read the articles themselves.
The talk focussed on two issues: short-term effects of consuming protein on protein synthesis and chronic effects of consuming protein on protein synthesis.
In the short term (i.e. protein synthesis that is triggered by consuming of protein, both at rest and after exercise), the main take home messages were:
a) there is a plateau effect of protein synthesis with respect to the amount of protein consumed (i.e. dose response). That is, consuming higher than 10-15 g of protein post-workout did not result in a substantial increase in protein synthesis. Practice modification: Stop consuming 20-40g of protein in your post-workout drinks.
b) the type of protein is not a factor in the magntitude of protein synthesis. Whether the protein was soy, whey, powder (i.e. free amino acids) or food (i.e. intact proteins), all sources provoked the same effect in terms of protein synthesis. Practice modification: 2 cups of milk provides 16g of protein and is a cheaper alternative to protein powders (though, 2 cups of milk is a fair volume of fluid to consume at once).
c) timing was not as large of an issue in short-term response to protein consuming. Subjects who consumed protein immediately after their workout experienced the same protein synthesis response as subjects who consumed protein 3 hours later. However, protein synthesis could be "reprimed" if one consumed 10g of protein immediately after and then 3 hours later when the levels of protein synthesis have come down. Practice modification: Don't obsess too much about when you take the protein post-workout; but it's still a good idea to consume protein right after your workout; and taking a second bolus of protein a couple of hours later is likely beneficial.
In the long term, basically, just one take home message:
a) the protein synthesis response becomes blunted with chronic training, BUT the dose-response plateau still occurs at about 10 grams. Therefore, higher doses of protein do not "correct" for the blunting. Practice modification: Periods of de-training may be more essential than we realized with respect not only to performance and avoidance of over-training/over-reaching, but also with respect to protein synthesis. This makes intuitive sense, but very few "casual athletes" realize this.
There was significant emphasis in the debate that protein requirements are likely different between different individuals and different athletic populations, so these conclusions are not the defininitive answer.
There was SIGNIFICANT concern about individuals (particularly females) trying to lose weight and therefore increasing protein consumption at the expense of other nutrients like carbohydrates and fats, since there are concerns regarding both nutrient and energy balance as well as other issues such as cholesterol, and female triad issues. This was also reflected in a few comments about both the Atkins and South Beach diets as being inappropriate paradigms due to possible misinterpretation of allowable food choices. This isn't to condemn the diets, but to say that their message isn't being communicated clearly, leading to individuals sacrificing needed carb and fat nutrients in favour of protein.
With respect to RDI's (recommended daily intakes) of protein, it seems that 0.8g per KILOGRAM of bodyweight is still the very broad, general RDI for everyone with the caveat that everyone is different and that 0.8g/kg may not be appropriate for everyone--but we all knew that already, right? However, 1g per POUND bodyweight was considered definitely excessive and even 1.2g/KG of body weight was considered by some to be over-consumption, even for most elite athletes.
Better sell my stock in the protein supplement industry!
Thanks for the info, bryanc! Basically, it sounds like all the recommendations about post w/o protein supplementation are money down the tubes if you're eating a balanced diet on a regular basis. Once again, Mom was right!
I'm still going to buy mine. Remeber those studies in the eighties about steroids not increasing muscle mass while the bodybuilding community with duh!
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Doesn\'t cross training sound like something Jesus could have benefited from?
Oh yeah, I'm still going to with continue what's worked for me, and what I've read from people like Berardi. It's an interesting study, but I've yet to read the details of it, and it is only a single, isolated study.
Actually, it's a conglomeration of several studies, not just an isolated one. Colloquiums are designed to present the "leading edge" summary of the research in the subject field of the colloquium. But as the lead speaker said, (and I paraphrase), "The pope and the surgeon general could get together and make a statement about protein overconsumption based on the evidence and people still wouldn't believe it."
I thought I saw John Berardi at the protein talk, but it was someone else. John B was at the conference though.
Originally posted by bryanc: Actually, it's a conglomeration of several studies, not just an isolated one. Colloquiums are designed to present the "leading edge" summary of the research in the subject field of the colloquium. But as the lead speaker said, (and I paraphrase), "The pope and the surgeon general could get together and make a statement about protein overconsumption based on the evidence and people still wouldn't believe it."
I thought I saw John Berardi at the protein talk, but it was someone else. John B was at the conference though.
That's cool. I wasn't trying to discredit you there. I'm just very careful about believing "the newest thing", and this is the first (and only) place I've heard of it. Like I said, I'd like to read more about it!
My initial question is "What kind of excercise and at what intensity?"
Was this light cardio for 30 minutes or all out ball busting weight training for 60?
Since the balance between protein breakdown and protein synthesis governs muscle protein turnover, you need to increase your protein turnover rates in order to best improve your muscle quality. A high protein diet does just this. By increasing both protein synthesis and protein breakdown, a high protein diet helps you get rid of the old muscle more quickly and build up new, more functional muscle to take its place.
among many other reasons for a higher protein diet.
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I don't wait for moods. You accomplish nothing if you do that. Your mind must know it has got to get down to work. - Pearl Sydenstrickter Buck
Well, I'm defending my thesis in 19 days, so I'm not about to go checking on OTHER papers until after that. Type of training was weightlifting. Intensity, I have no idea. But I will tell you that protein synthesis was expressed as NET synthesis, not gross, in response to both simply a bolus of protein at rest and after weight lifting.
Consider this though: How does consumption of greater amounts of protein increase protein turnover (i.e. increasing rates of degradation and synthesis)? What's the mechanism that ingestion of higher amounts of protein would cause increased protein turnover? Ingestion of protein increases amino acid availability, but the rates at which proteins are degraded and synthesized are not dependent on amino acid availability past what appears to be approximately the 10 gram mark. Once positive nitrogen balance is attained, the body begins to process excess nitrogren to get rid of it, since excess nitrogen is toxic.
Albeit, there is very little evidence to show that a high protein diet does not adversely affect kidney function for the most part, in healthy individuals, but given that there is very little additional net protein synthesis that occurs for doses of protein above 10 grams post exercise, it seems excessive to consume much more than that.
Don't forget that the entire emphasis on net protein synthesis is dependent on the "breakdown, rebuild" model of muscle growth, which is still a relatively unproven theory, despite its wide acceptance as the most prominent theory.
I would guess that they didn't even consider such things in a presentation like this, and unless I misunderstood it was mainly focused on "athletes".
But I see where you're going with this (I think) and I agree. It seems that health professionals think people will eat too much protein, which I doubt rarely happens in the general public. (I'm not sure this applies to the information presented--probably not.) More importantly, if some protein is substituted for carbs in the general public--say, in a hypocaloric diet--it should increase the rate of weight loss due to gluconeogenesis as well as the thermic effect of protein.
Amino acids are important in maintaining the body's nitrogen balance. This positive nitrogen balance means that muscle growth is occurring. To achieve such a balance, a hard training body builder MUST take in more protein to build up the components of growing muscle tissue. Body builders need about 1.2-1.6 grams of protein per pound of bodyweight per day to fully sustain the process of muscular growth and repair. For a 200 lb. plus individual eating six meals a day this works out to 33-41 grams of protein per meal.
it's also a common believe that is it not the form of the amino acid that is crucial, but the proportions in which the amino acid reach the muscle. This compensation is necessary because intensive resistance training creates specific metabolic demands. Those needs result in a disproportionate consumption of certain amino acids for energy production and other non anabolic needs. The ability of the body to absorb and utilize amino acids can be exploited to produce an anabolic effect.
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Doesn\'t cross training sound like something Jesus could have benefited from?
Originally posted by dinabol: Body builders need about 1.2-1.6 grams of protein per pound of bodyweight per day to fully sustain the process of muscular growth and repair. For a 200 lb. plus individual eating six meals a day this works out to 33-41 grams of protein per meal.
Bullshit. Show me the evidence. For any of this.
Positive nitrogen balance simply means that more nitrogen is being produced through the metabolism of excess protein. Nitrogen is a waste product. The fact that you are in positive nitrogen balance simply means that your body is getting rid of excess protein (i.e. congratulations, we have more than enough right now). Being "more positive" in nitrogen balance doesn't mean anything other than the fact that your body is getting rid of more excess protein (and even "positive nitrogen balance" has a ceiling limited partly by the glomular filtration rate in your kidneys). It is not a proxy indicator for muscle synthesis since the rate at which protein is synthesized is NOT governed by how much protein is in excess in your body at any given time.
Quote:
Originally posted by dinabol: it's also a common believe that is it not the form of the amino acid that is crucial, but the proportions in which the amino acid reach the muscle. This compensation is necessary because intensive resistance training creates specific metabolic demands. Those needs result in a disproportionate consumption of certain amino acids for energy production and other non anabolic needs. The ability of the body to absorb and utilize amino acids can be exploited to produce an anabolic effect.
Again, I'll call your shovelling:
First off, I have no idea by what you mean by "the form of the amino acid". Are you talking about protein structure or just the type of amino acid (eg. proline, glutamine)? How is the "proportions of amino acids that reach the muscle" regulated? If we don't know how it's regulated, how do we know it's important?
What exactly are you refering to by "This compensation"? What compensation? And what metabolic demands are you talking about when you say, "intensive resistance training creates specific metabolic demands"? Your explanations are both incredibly general and vague.
Hey look, I can do this too:
The consumption of pink marshmellows produces a metabolic response that results in several physiological and metabolic changes. It's a common belief that these pink marshmellows alter metabolic activity to encourage changes in the concentration of nutrients in the blood. Thus, eating pink marshmellows can be exploited to produce a metabolic effect that affects...things.
Hows does the thermic effect of protein factor in to this theory?
Hey Miszu1,
The focus of the talk was protein requirements in athletes, so we didn't talk at all about thermic effects, since athletes don't typically consume more protein for the thermic effect. So the main factor of concern in this particular debate was the effect of protein on protein synthesis, which was used as a proxy for muscle synthesis.
The thermic effect of protein is typically desireable in individuals who want to lose weight--or rather experience a higher resting metabolic rate post-activity/consumption of proteins so that their net caloric expenditure over the day is negative, or at least not positive. Muscle synthesis is an anabolic process and therefore, the thermic effect, while present, isn't of large concern, since a net excess or at least a lack of net deficit calories is required for synthesis to happen in any constructive capacity with respect to muscle building.
The concern of the panel was mainly regarding female athletes and specifically, the female triad (ammenorrhea, eating disorder and decreased bone density). The concern was that there was an ancedotal increasing trend in female athletes (particularly in sports where aesthetics are of higher "importance) to consume higher amounts of protein to lose weight, and substitute carbs and fats with protein (i.e. the mass of food either doesn't change or decreases, but the proportions of proteins, carbs and fats shifts dramatically to the protein side). Not only are there observations of female triads, but many of these athletes are not meeting their energy requirements for performance because protein is not a good primary energy source of high performance athletes.
You call it shoveling I call it body building. Something I do by the way. And, I could show you evidence but knowing you you would find something wrong with it so why bother? the study this and the study that. body builders(me included),lost a
lot of respect for the research community when they FINALLY
Dscovered that steroids increase muscle mass. Duh? we knew that for years. Just like we know this.
it is the proportions of amino acid comsumption. If someone is off by just one amino acid it can hamper protein synthesis by as much as 50%. The amino acid usually lacking is methionine.
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Doesn\'t cross training sound like something Jesus could have benefited from?
Far be it for me to argue with the anecdotal evidence of a bodybuilder. Cuz they're never wrong either...
Methionine is found in abundance in almost every protein source: milk, eggs, nuts, beans, dairy products, meats. How would one be "short" on methionine?
Originally posted by DANZIG: why are people so pompous on this board. damn
Because it's the crap that gets spouted around that decreases the overall quality of the information on this board.
If we're going to subscribe to a philosophy that information presented in this forum should be high quality, evidence based information, then that's what it should be. That's the reason why I started posting in this forum in the first place. If we're all going to veer towards another t-mag or even MH forum where the unsubstantiated claims fly like so much...stuff in a fan, then that's fine too. Just let me know. I'll adjust my posts accordingly.
Myth #2: You can only assimilate 30 grams of protein at one sitting.
Fact: The body has the ability to digest and assimilate much more than 30 grams of protein from a single meal.
Speaking of high intakes of protein, people have been perpetuating the myth that you can only assimilate ~30 grams of protein at a time, making protein meals any greater than a 6 oz. chicken breast a waste. This is anything but true. For example, the digestibility of meat (i.e. beef, poultry, pork and fish) is about 97% efficient. If you eat 25 grams of beef, you will absorb into the blood stream 97% of the protein in that piece of meat. If, on the other hand, you eat a 10 oz steak containing about 60 grams of protein, you will again digest and absorb 97% of the protein. If you could only assimilate 30 grams of protein at a time, why would researchers be using in excess of 40 grams of protein to stimulate muscle growth?1
Critics of high protein intakes may try to point out that increased protein intake only leads to increased protein oxidation. This is true, nevertheless, some researchers speculate that this increase in protein oxidation following high protein intakes may initiate something they call the "anabolic drive".13 The anabolic drive is characterized by hyperaminoacidemia, an increase in both protein synthesis and breakdown with an overall positive nitrogen balance. In animals, there is a correspondent increase in anabolic hormones such as IGF-1 and GH. Though this response is difficult to identify in humans, an increase in lean tissue accretion does occur with exaggerated protein intakes.14,15
The take home message is that, if you are going to maximize muscle growth you have to minimize muscle loss, and maximize protein synthesis. Research clearly shows this is accomplished with heavy training, adequate calories, and very importantly high protein consumption. This means that meals containing more than 30 grams of protein will be the norm. Not to worry, all that protein will certainly be used effectively by the body.
Here are the studies listed at the end of that article. They look pretty old to me.
1. Tipton K., Ferrando A., Phillips S., Doyle, JR D., Wolfe R. Post exercise net protein synthesis in human muscle from orally administered amino acids. Am. J. Physiol. 276: E628-E634, 1999
2. Bennet, W. M., A. A. Connacher, C. M. Scrimgeour, and M. J. Rennie. The effect of amino-acid infusion on leg protein turnover assessed by L-[15N]phenylalanine and L-[1-13C]leucine exchange. Eur. J. Clin. Invest. 20: 37-46, 1989
3. Castellino, P., L. Luzi, D. C. Simonson, M. Haymond, and R. A. DeFronzo. Effect of insulin and plasma amino acid concentrations on leucine metabolism in man. J. Clin. Invest. 80: 1784-1793, 1987
4. Fryburg, D. A., L. A. Jahn, S. A. Hill, D. M. Oliveras, and E. J. Barrett. Insulin and insulin-like growth factor-I enhance human skeletal muscle protein anabolism during hyperaminoacidemia by different mechanisms. J. Clin. Invest. 96: 1722-1729, 1995
5. McNulty, P. H., L. H. Young, and E. J. Barrett. Response of rat heart and skeletal muscle protein in vivo to insulin and amino acid infusion. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E958-E965, 1993
6. Mosoni, L., M. Houlier, P. P. Mirand, G. Bayle, and J. Grizard. Effect of amino acids alone or with insulin on muscle and liver protein synthesis in adult and old rats. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E614-E620, 1993
7. Newman, E., M. J. Heslin, R. F. Wolf, P. T. W. Pisters, and M. F. Brennan. The effect of systemic hyperinsulinemia with concomitant infusion of amino acids on skeletal muscle protein turnover in the human forearm. Metabolism 43: 70-78, 1994
8. Watt, P. W., M. E. Corbett, and M. J. Rennie. Stimulation of protein synthesis in pig skeletal muscle by infusion of amino acids during constant insulin availability. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E453-E460, 1992
9. Newsholme, A.E., Parry-Billings M. Properties of glutamine release from muscle and its importance for the immune system. JPEN. 14 (4) supplement S63-67
10. Oddoye EA., Margen S. Nitrogen balance studies in humans: long-term effect of high nitrogen intake on nitrogen accretion. J Nutr 109 (3): 363-77
11. Boirie Y, Dangin M, Gachon P, Vasson M-P, Maubois J-L, and Beaufrère B. Slow and fast dietary proteins differently modulate postprandial protein accretion (amino acid turnover / postprandial protein anabolism / milk protein / stable isotopes) Proc. Natl. Acad. Sci. USA Vol. 94, pp. 14930-14935, December 1997
12. Sarwar G. The Protein Digestibility-Corrected Amino Acid Score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 127: 758-764, 1997
13. Millward, D.J. Metabolic demands for amino acids and the human dietary requirement: Millward and Rivers (1988) revisited. J. Nutr. 128: 2563S-2576S, 1998
14. Fern EB, Bielinski RN, Schutz Y. Effects of exaggerated amino acid and protein supply in man. Experientia 1991 Feb 15;47(2):168-72
15. Dragan, GI., Vasiliu A., Georgescu E. Effect of increased supply of protein on elite weight-lifters. In:Milk Protein T.E. Galesloot and B.J. Tinbergen (Eds.). Wageningen The Netherlands: Pudoc, 1985, pp. 99-103
It's not whether the protein can be processed or not, the issue here is very narrow--much more narrow than I think we have been discussing. The issue here is the effect of protein ingestion following a weight workout on net protein synthesis, and whether more protein consumption has any greater effect on net protein synthesis; and the answer seems to be that past 10g of protein, there is no significant additional increase in net protein synthesis.
Two of the references provided in the hypertrophy site are from 1991 and 1985, so they're hardly up to date, but like I said, I'm not going to have time to review much of anything until after my defense is done. So once it IS done, I'll go into the primary sources of both this talk and the overall debate and see what's there and what isn't.
Ironically, the one reference (number 1 in that list) on megadoses of protein is from the Wolfe/Tipton group whose more recent work formed much of the basis of the work presented at this talk. So, perhaps things have changed since 1999.
Body builders need about 1.2-1.6 grams of protein per pound of bodyweight per day to fully sustain the process of muscular growth and repair.
Dinabol's above comment isn't substantiated by scientific evidence, and I guess you could even say it's refuted by one of Tarnolpolsky's studies. That said, if we're talking bodybuilder's who are "juicing", then I wouldn't be surprised if they could put that extra protein consumption to good use. I imagine that you'd find a lack of evidence for it since you'd have to have a study whose purpose is to find out the protein needs of lifters taking steriods, which isn't getting funded and few scientists would have an interest in (besides maybe just their curiosity).
To me, though, if you're a non-juicing lifter who's trying to ensure that you're fulfilling your body's protein needs, it makes sense to ingest your protein in equal amounts throughout the day--say 30 to 40 grams at a time, five times a day. That would help make sure that essential amino acids were available at all times for protein synthesis, and I have heard this advice from many experts including Lemon at Western Ontario. According to his reviews, appropriate protein intake for lifters is 1.6 to 1.8 g/kg body mass, which is getting close to one gram per pound of body weight if you round up for ease of calculation. I can't see how there's anything "wrong" with this for people trying to pack on muscle. (This, obviously, isn't meant to argue a case against the information presented in the seminar Bryan attended.)
However, I don't understand Dinabol's amino acid comments either. Yes, you need available amino acids. You also need available essential amino acids. Eat a high-quality protein (eggs, for instance) and you'll get them.
Wolfe and Tipton have shown the amino acid requirements needed to increase net muscle protein synthesis after resistance training are pretty low--around six grams, right? (That's not the same as six grams of protein, though.) I know Kevin Tipton and he's no "skinny science geek". He not only works in a lab with some of the most advanced equipment in the world, he also lifts. And I can assure you that he looks at this stuff from a scientific AND practical standpoint. In addition, no bodybuilder understands protein synthesis better than he does (and few people in the world probably do). So even if popular bodybuilding recommendations are proven right (for non-juicing bodybuilders) down the road, it's likely to be for completely different reasons than what the explanation is now. (I'm saying that perhaps the recommendations are right, but the current logic is probably wrong.)
The following (in quotes below) was taken from a review by Tipton (and Wolfe) and I think gets to the point of what Bryan was saying. I'd also say that for the sake of debates, most of us are only going to speak in terms of "natural" lifters, since that's our focus. I have no problem with ADULTS that take steroids intelligently (although I suspect that there are few out there), but for the most part, they're probably a different audience than the members of this board.
"The main determinants of an athlete's protein needs are their training regime and habitual nutrient intake. Most athletes ingest sufficient protein in their habitual diet. Additional protein will confer only a minimal, albeit arguably important, additional advantage. Given sufficient energy intake, lean body mass can be maintained within a wide range of protein intakes. Since there is limited evidence for harmful effects of a high protein intake and there is a metabolic rationale for the efficacy of an increase in protein, if muscle hypertrophy is the goal, a higher protein intake within the context of an athlete's overall dietary requirements may be beneficial. 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. Current literature suggests that it may be too simplistic to rely on recommendations of a particular amount of protein per day. Acute studies suggest that for any given amount of protein, the metabolic response is dependent on other factors, including the timing of ingestion in relation to exercise and/or other nutrients, the composition of ingested amino acids and the type of protein."
Dr. Tipton was at the talk as well (though not as a panelist). The next "big" thing in this area will likely be focused around timing issues, rather than actual quantities of consumption.
Precisely. (Pardon the pun.) Timing is appears to be so much more important than quantity. (I think in the past quantity made up for lack of knowledge about timing.)
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