begin to dig

Sunday, February 21, 2010

begin2dig joins the 21st century: facebook and twitter

Follow @mcphoo Having struggled with how to do facebook, and having wrestled with frustrating my non-fitness geek colleagues on twitter with all this wellbeing info stuff, i have, in reading a wee ebook called "crush it" learned that i can clear the field for better communication(thanks miketnelson for the pointer).

So to connect better, learn more, share our good STUFF:

begin2dig now has its own facebook page:
(url: http://www.facebook.com/pages/begin2dig-b2d/321154145333)

the goal is to have ongoing discussions about topics raised here where comments may seem too formal (though i'd love to engage with folks with more comments)
begin2dig now has its own twitter feed:
(url: http://twitter.com/begin2dig)

even faster exchanges on topics - please @begin2dig me! (is that a verb?)

The current icon for these sites is just below.
duh? duh.

i hope (really, i do) that you'll consider adding these links to your rich social networking space.

A goodly number of folks come through b2d daily, and thank you! but i hear from few of y'all in the comments.

Comments i know take time - so i hope you'll consider that FB and Twitter may facilitate faster contact.

And of course you can still connect with b2d via RSS feed and via Email for instant updated as soon as a new blog post is published.

AND to those who put their faces right out there on this site to say they Grok B2D, wow, thank you. Glad you're here.

Thanks again for stopping by & taking time to have b2d info as part of your infosphere

best
mc

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Saturday, February 20, 2010

Improving Longevity with Calorie Reduction in Humans?

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Lots of studies on rats and a few other mamals have seemed to

show the benefit of caloric reduction and longevity - mainly it seems in the way that CR impacts core temperature (a bit lower is better), fasting insulin levels, and oxidative stress - that free radical stuff. Testing CR and humans is going to be trickier. So researchers a few years ago looked at simply the effects of CR on these very markers that have been hypothesised to have an effect on longevity. What their work shows is that yup, CR has these effects.

The resson i mention this piece here is that neither Alan Aaragon's 2007 critique of IF (which i've cited before as a good ref and which Chris over at conditioning resaerch has also detailed); nor have i seen the work referenced in the more recent Eat Stop Eat by Brad Pilon.

So here's the abstract; the full article is also available for free, which is nice.

JAMA. 2006 Apr 5;295(13):1539-48.
Effect of 6-month calorie restriction on biomarkers of longevity, metabolic adaptation, and oxidative stress in overweight individuals: a randomized controlled trial.

Heilbronn LK, de Jonge L, Frisard MI, DeLany JP, Larson-Meyer DE, Rood J, Nguyen T, Martin CK, Volaufova J, Most MM, Greenway FL, Smith SR, Deutsch WA, Williamson DA, Ravussin E; Pennington CALERIE Team.

Pennington Biomedical Research Center, Louisiana State University, Baton Rouge 70808, USA.

Erratum in:* JAMA. 2006 Jun 7;295(21):2482.

Comment in: * JAMA. 2006 Apr 5;295(13):1577-8.
CONTEXT: Prolonged calorie restriction increases life span in rodents. Whether prolonged calorie restriction affects biomarkers of longevity or markers of oxidative stress, or reduces metabolic rate beyond that expected from reduced metabolic mass, has not been investigated in humans. OBJECTIVE: To examine the effects of 6 months of calorie restriction, with or without exercise, in overweight, nonobese (body mass index, 25 to <30) men and women. DESIGN, SETTING, AND PARTICIPANTS: Randomized controlled trial of healthy, sedentary men and women (N = 48) conducted between March 2002 and August 2004 at a research center in Baton Rouge, La. INTERVENTION: Participants were randomized to 1 of 4 groups for 6 months: control (weight maintenance diet); calorie restriction (25% calorie restriction of baseline energy requirements); calorie restriction with exercise (12.5% calorie restriction plus 12.5% increase in energy expenditure by structured exercise); very low-calorie diet (890 kcal/d until 15% weight reduction, followed by a weight maintenance diet). MAIN OUTCOME MEASURES: Body composition; dehydroepiandrosterone sulfate (DHEAS), glucose, and insulin levels; protein carbonyls; DNA damage; 24-hour energy expenditure; and core body temperature. RESULTS: Mean (SEM) weight change at 6 months in the 4 groups was as follows: controls, -1.0% (1.1%); calorie restriction, -10.4% (0.9%); calorie restriction with exercise, -10.0% (0.8%); and very low-calorie diet, -13.9% (0.7%). At 6 months, fasting insulin levels were significantly reduced from baseline in the intervention groups (all P<.01), whereas DHEAS and glucose levels were unchanged. Core body temperature was reduced in the calorie restriction and calorie restriction with exercise groups (both P<.05). After adjustment for changes in body composition, sedentary 24-hour energy expenditure was unchanged in controls, but decreased in the calorie restriction (-135 kcal/d [42 kcal/d]), calorie restriction with exercise (-117 kcal/d [52 kcal/d]), and very low-calorie diet (-125 kcal/d [35 kcal/d]) groups (all P<.008). These "metabolic adaptations" (~ 6% more than expected based on loss of metabolic mass) were statistically different from controls (P<.05). Protein carbonyl concentrations were not changed from baseline to month 6 in any group, whereas DNA damage was also reduced from baseline in all intervention groups (P <.005). CONCLUSIONS: Our findings suggest that 2 biomarkers of longevity (fasting insulin level and body temperature) are decreased by prolonged calorie restriction in humans and support the theory that metabolic rate is reduced beyond the level expected from reduced metabolic body mass. Studies of longer duration are required to determine if calorie restriction attenuates the aging process in humans.

Now, i haven't seen a comparison of these same markers considered in a study where folks are JUST exercising and eating right (say a la precision nutrition's principles), but that is what folks like Aragon suggest - that exercise and diet have the same effects. A head to head study or gathering of results would be nice.

There is a nice 2009 follow up study by this group that looks at metabolic adaptation of folks on CR and CR + exercise. Bottom line: the folks who keep exercising while on the CR do not experience a metabolic adaptation like the *just * CR's (in other words the CR's metabolism really drops, and so does their activity). IS that maintenance good for longevity markers? not clear. But in terms of weight loss maintenance, surprise surprise:

Interestingly, despite similar body mass and composition changes, CR in conjunction with exercise (CR+EX) did not result in a metabolic adaptation. If weight relapse does occur in part as a result of a reduced metabolic rate in the weight reduced state, then perhaps the combination of CR and exercise may be the best choice of intervention to prevent weight regain in overweight and obese individuals. Certainly, more than 20 years ago, Pavlou observed that exercise during a CR-induced weight loss program was essential for success of weight loss maintenance [34]. Since then others have shown with doubly labeled water studies that weight stability following weight loss is sustained by higher levels of activity related energy expenditure and free-living physical activity [35], [36]. To our knowledge no studies have prospectively studied the energetic adjustments of CR only versus CR in conjunction with exercise during weight loss and weight loss maintenance.

SO diet, combined with exercise is still a good thing for maintaining ongoing body comp goals. Great.

Oh and to put icing on the cake of why exercise with diet (spliting the total CR between diet and exercise) is a good thing, the gang just published a study showing that while fat loss is the same no matter how you get you mojo on and calories off, with exercise is better:

Med Sci Sports Exerc. 2010 Jan;42(1):152-9.
Caloric restriction with or without exercise: the fitness versus fatness debate.

Larson-Meyer DE, Redman L, Heilbronn LK, Martin CK, Ravussin E.

Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA. enette@uwyo.edu

There is a debate over the independent effects of aerobic fitness and body fatness on mortality and disease risks. PURPOSE: To determine whether a 25% energy deficit that produces equal change in body fatness leads to greater cardiometabolic benefits when aerobic exercise is included. METHODS: Thirty-six overweight participants (16 males/20 females) (39 +/- 1 yr; 82 +/- 2 kg; body mass index = 27.8 +/- 0.3 kg x m2, mean +/- SEM) were randomized to one of three groups (n = 12 for each) for a 6-month intervention: control (CO, weight-maintenance diet), caloric restriction (CR, 25% reduction in energy intake), or caloric restriction plus aerobic exercise (CR + EX, 12.5% reduction in energy intake plus 12.5% increase in exercise energy expenditure). Food was provided during weeks 1-12 and 22-24. Changes in fat mass, visceral fat, VO2peak (graded treadmill test), muscular strength (isokinetic knee extension/flexion), blood lipids, blood pressure, and insulin sensitivity/secretion were compared. RESULTS: As expected, VO2peak was significantly improved after 6 months of intervention in CR + EX only (22 +/- 5% vs 7 +/- 5% in CR and -5 +/- 3% in CO), whereas isokinetic muscular strength did not change. There was no difference in the losses of weight, fat mass, or visceral fat and changes in systolic blood pressure (BP) between the intervention groups. However, only CR + EX had a significant decrease in diastolic BP (-5 +/- 3% vs -2 +/- 2% in CR and -1 +/- 2% in CO), in low-density lipoprotein (LDL) cholesterol (-13 +/- 4% vs -6 +/- 3% in CR and 2 +/- 4% in CO), and a significant increase in insulin sensitivity (66 +/- 22% vs 40 +/- 20% in CR and 1 +/- 11% in CO). CONCLUSIONS: Despite similar effect on fat losses, combining CR with exercise increased aerobic fitness in parallel with improved insulin sensitivity, LDL cholesterol, and diastolic BP. The results lend support for inclusion of an exercise component in weight loss programs to improve metabolic fitness.

In the meantime of waiting for the longevity marker comparison where the condition would be

normal healthy eating (like PN) and exercise, there seems to be at least a few of us who are using say precision nutrition approaches to eating/health on most days (and getting questions on nutrition addressed) and ESE fasting once or twice a week - for me this protocol is an exploration; nothing definitive, but intriguing. Just FYI

Related Posts

Citations:
Heilbronn, L. (2006). Effect of 6-Month Calorie Restriction on Biomarkers of Longevity, Metabolic Adaptation, and Oxidative Stress in Overweight Individuals: A Randomized Controlled Trial JAMA: The Journal of the American Medical Association, 295 (13), 1539-1548 DOI: 10.1001/jama.295.13.1539

Redman, L., Heilbronn, L., Martin, C., de Jonge, L., Williamson, D., Delany, J., Ravussin, E., & , . (2009). Metabolic and Behavioral Compensations in Response to Caloric Restriction: Implications for the Maintenance of Weight Loss PLoS ONE, 4 (2) DOI: 10.1371/journal.pone.0004377

LARSON-MEYER, D., REDMAN, L., HEILBRONN, L., MARTIN, C., & RAVUSSIN, E. (2010). Caloric Restriction with or without Exercise Medicine & Science in Sports & Exercise, 42 (1), 152-159 DOI: 10.1249/MSS.0b013e3181ad7f17 Follow @begin2dig

Friday, February 19, 2010

8lbs of Lean Mass in One Workout - and other surprises Feb 24 - from brad pilon

Follow @mcphoo Apropos of all this discourse on protein synthesis vs absorption vs muscle mass gain, this just in from brad pilon (yes of eat stop eat fame). How to add 8lbs of lean mass in one workout. i love it

The main idea? Check out the video and register for a teleseminar (it's free) to find out more insider knowledge about how supplement companies make some of the outrageous claims they do - with seeming results.
But get some good tips too. Taken from the teleseminar page:

* How many calories it REALLY takes to build muscle

* Why HEIGHT has more to do with the amount of calories you need on a daily basis and how to use the "Rule of 7's and 3's" to determine how BIG you'll actually end up

* A sneaky trick that all marketers use to get you to THINK that you're gaining more muscle than you really are... and how this same sneaky trick is SAPPING you out of your hard earned money in the process

* How adding just 5 lbs of muscle in JUST THE RIGHT PLACES gives the illusion of a 25 lb increase in size... DRUG FREE...

* The TRUTH on testimonials and "before and after" pics and how EVEN YOU can make yourself look super huge in 24 hours... without ever touching the inside of a gym or taking a "magic powder". This is the one secret the supplement companies DON'T WANT YOU TO KNOW

(here's a preview on the above one from brad's blog, 2007:

how to gain 10 pounds of muscle and lose 5 pounds of fat in only 2 days.

Note: the above link to the seminar links back to me, but the seminar is free, so it seems that it's for counting purposes - but heck if you'd like to buy a copy of eat stop eat from my site (it's a good researched read whether you practice fasting or not) that's lovely, too (more about affiliate links at b2d)

Aside: as i've said before, colleagues i trust (and now me, too) are blending precision nutrition with eat stop eat for
great nutrition knowledge (overview), and exploration of the benefits/vibes of fasting.

Anyway, the seminar sounds like it's going to be fun. Let me know what you think.

Oh and as one more place to get psyched for what promises to be a fun evening, here's an interview Mike T Neslon did with Mr. Pilon.

mc Follow @begin2dig

Curb my protein enthusiasm: single factor thinking fails again

Follow @mcphoo Yesterday i wrote a piece reviewing an article that showed that 30g of whole protein was all that could be synthesized by resting muscle, so we can all just chill about how much protein we take in at a feeding. And indeed, there's one more reason to spread out one's protein intake over the course of a day. One more reason (not the only reason) Mutliple feedings rock!

I have just finished revising that article to be far more restrained in its celebration. I think it's a much better/fairer piece now, anyway. Dam it. Because now while more accurate, it's far less conclusive.

This revision fervour first started with some interesting conflations i was hearing between absorption and synthesis - how are these related, and conflations between some folks saying one MUST take on 30g of protein every few hours vs what the article suggested - that's the MAX one could utilize - if one is 80kg or thereabouts, not what one *should* take on. Minimums aren't established; only maxs. And only for acute uptake. With the interesting finding that this result seems age and gender independent.

Then i went back to my minute with Mike about the Protein Window and how that doesn't really close in a day - so why would protein only be usable to that max amount in that 3hr window of the study?

Then i checked a few references looking at lean mass over time with one meal vs three meals (no grazing just 1 or 3), and lean muscle maintenance (see revised post for the details)

And then to cap it all off Chris Highcock of conditioning research kindly pointed me at Eat STop Eat Brad Pilons How Much Protein, and well, what's the take away if you don't feel like going back to look at the study (where all the refs to the following points are):

Acute responses to muscle protein synthesis are not necessarily the same as lean mass maintenance or growth over time
If one's thinking mass building thoughts the exercise and creatine may be more critical than protein
Protein timing may not be an issue for muscle mass. The pluses of nutrient timing may be elsewhere found - like glucose and other hormone regulation/performance.

What *is* reinforced in the related work with the study presented is that more likely than not LESS is more - whether at rest or working out. That the 70-120 g range may be just as productive at mass building as any higher amounts, and that if one goes for higher protein amounts (like 160 grams if 80kg), while one's system can safely absorb that, it mayn't be using it for muscle building.

Once again, single factor thinking dun't work - well. Creatine in the mix does. Precision Nutrition (very multi-factor) does; Chris Highcock does. Mike T. Nelson does. Georgie Fear does and so it seems does Brad Pilon. and i'd like to, too, though it may take me a few tries. Follow @begin2dig

Thursday, February 18, 2010

30g of protein per meal for optimal muscle building? That Depends - a lot

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Less and More? Yes, when talking protein. Have you encountered any of these questions? How much protein can i eat at a sitting? What's the right amount of protein to eat? How much protein can i absorb? These are questions in the fitness world that get asked all the time - especially by folks who want to optimize their muscle growth. The answer seems to be "less than you think, but more often"

We know there's a usual formula (even that's been debated at a Protein Roundtable - but not by much) about how much protein to take in in a day - let's just say for now it's 2-2.5 g per kg (based on work in 2006), or about a g/pound (nice mix of metric and imperial there) which has been pretty much the standard recommendation for some time, newly validated. As the authors note, that's about 176 g of protein a day for an 80kg person " This is well below the theoretical maximum safe intake range for an 80 kg person (285 to 365 g/d)."

Intriguingly, there's a newish study out to show that 30g of protein derived from real food is about all the protein one can reasonably ingest in a sitting that will support muscle or protein synthesis is 30g. There are certain conditions attached to this statement that we'll discuss below.

Also Note, muscle protein synthesis here is being looked at in a particular context. We're talking about what resting muscle can use to handle the ongoing breakdown and build up of muscle proteins. This is potentially different than a body builder working out to build lots of mass. In other words, we're looking at a kind of baseline max.

SO 30g of whole protein or, in the case of this study, a 113g serving of lean beef (about 4oz). That's pretty close to the traditional portion size of a piece of meat the size of a deck of cards.

We can eat more protein at one meal, but the authors would argue, it ain't doing anything for muscle building/protein synthesis of resting muscles. Here's the overview of the research:

A Moderate Serving of High-Quality Protein Maximally Stimulates Skeletal Muscle Protein Synthesis in Young and Elderly Subjects

T. Brock Symons PhD, Melinda Sheffield-Moore PhD, Robert R. Wolfe PhD and Douglas Paddon-Jones PhDCorresponding Author Contact Information, E-mail The Corresponding Author
Accepted 30 January 2009.
Available online 21 August 2009.

Abstract

Ingestion of sufficient dietary protein is a fundamental prerequisite for muscle protein synthesis and maintenance of muscle mass and function. Elderly people are often at increased risk for protein-energy malnutrition, sarcopenia, and a diminished quality of life. This study sought to compare changes in muscle protein synthesis and anabolic efficiency in response to a single moderate serving (113 g; 220 kcal; 30 g protein) or large serving (340 g; 660 kcal; 90 g protein) of 90% lean beef. Venous blood and vastus lateralis muscle biopsy samples were obtained during a primed, constant infusion (0.08 μmol/kg/min) of L-[ring-13C6] phenylalanine in healthy young (n=17; 34±3 years) and elderly (n=17; 68±2 years) individuals. Mixed muscle fractional synthesis rate was calculated during a 3-hour postabsorptive period and for 5 hours after meal ingestion. Data were analyzed using a two-way repeated measures analysis of variance with Tukey's pairwise comparisons. A 113-g serving of lean beef increased muscle protein synthesis by approximately 50% in both young and older volunteers. Despite a threefold increase in protein and energy content, there was no further increase in protein synthesis after ingestion of 340 g lean beef in either age group. Ingestion of more than 30 g protein in a single meal does not further enhance the stimulation of muscle protein synthesis in young and elderly.

The authors cite their motivation for the study in part as a balance to previous work that showed 10g of EAA's at a go was all the body could make use of - that amounts beyond that signalled no greater muscle synthesis (or synthesis of muscle protein, more formally). So what about getting those EAA's from a whole food like "113 g lean beef, 30 g protein, 10 g EAAs, 220 kcal." Turns out that it *seems* it doesn't matter from whence one gets those EAA's, that's the max the body can use for " a maximal acute protein synthetic effect."

Indeed, in the discussion of their results at 30g the authors also speculate

In terms of stimulating muscle growth, it therefore seems likely that under resting/nonexercising conditions, consumption of more than 30 g protein in a single meal is not justified. Indeed, it may well be the case that a slightly smaller meal would produce a similar protein synthetic responseIn terms of stimulating muscle growth, it therefore seems likely that under resting/nonexercising conditions, consumption of more than 30 g protein in a single meal is not justified. Indeed, it may well be the case that a slightly smaller meal would produce a similar protein synthetic response.

Considerations: Could even less protein, in other words, have as much of a protein synthesis response as the 30g? Note the caveats given: if we're talking at rest and without exercise. The authors' participants were people who (a) didn't change their diet for the 72 hours leading up to the study (b) didn't do any activities for that period. THe study notes only that they were healthy people in a range of ages, not whether any were jocks or sedentary. Also, the average weight (plus or minus 7kg) was about 80kg in the "young" group and about 78 in the "elder" group. We also don't know what the lean mass is of any of the participants, or perhaps more fundamentally, how amount of protein might be impacted if one weights 20kg less or more than the study average?

One Feeding. The authors offer even more caveats: the researchers only looked at the ingestion of the whole protein - not at it mixed up with more food, as we usually get it, or after exercise. They say:

Perhaps the most obvious is the fact that a single menu item, such as a serving of lean beef, is seldom eaten alone. As noted, there are some data suggesting that elders may have a less robust protein synthetic response to the combined ingestion of protein and carbohydrate than their younger counterparts (25). This has yet to be explored in the context of an actual mixed-nutrient meal, but warrants further investigation. Further, there is the potential of an added protein synthetic response if protein were to be consumed in close temporal proximity to physical activity (29,30).

25 E. Volpi, B. Mittendorfer, B.B. Rasmussen and R.R. Wolfe, The response of muscle protein anabolism to combined hyperaminoacidemia and glucose-induced hyperinsulinemia is impaired in the elderly, J Clin Endocrinol Metab 85 (2000), pp. 4481–4490.
29 S.M. Phillips, J.W. Hartman and S.B. Wilkinson, Dietary protein to support anabolism with resistance exercise in young men, J Am Coll Nutr 24 (2005), pp. S134–S139.
30 M. Sheffield-Moore, C.W. Yeckel, E. Volpi, S.E. Wolf, B. Morio, D.L. Chinkes, D. Paddon-Jones and R.R. Wolfe, Postexercise protein metabolism in older and younger men following moderate-intensity aerobic exercise, Am J Physiol Endocrinol Metab 287 (2004), pp. E513–E522.

In other words the researchers only tested protein synthesis effects when chewing meat in isolation of other food stuffs. Yes that's right, that's all they got: a 90% lean beef patty. And yes, "this project was supported by funding from the National Cattlemen’s Beef Association Checkoff Program" But it was also funded by the NIH center on aging. And considering the findings suggest that less is just as good as more, it's not doing the cattleMEN's association a great service.

Where's the Beef for Application? What is intriguing to me in this study is how one would balance optimal absorption of protein with the amount of protein we're supposed to ingest - especially if remotely active. so our 80kg guy is going for 180ish grams of protein, at max 30g whole protein a meal.

So, let's say our person has three meals a day. 30g per meal, that's only 90g protein, total. That's half the protein our fella needs, according to the usual saw of .8-1g protein/pound of person.

Or what about folks who eat only one meal a day? That's one more potential problem with the evening feast beyond say glucose effects , then, perhaps? They may pig out on protein, but it's still 30g a shot for muscle synthesis this study would suggest. Read on.

Frequent Feedings for Optimal Muscle Building? Er...
Could this max 30g of whole protein be one more argument for the value of frequent meals during the day(s one eats -one may fast)? Consider one of the core heuristics of Precision Nutrition (discussed here): at each feeding make sure to have

some greens
some healthy fats
some protein
(starchy carbs only post workout).

6 feedings at 30g a shot would be just right for our 80 kg hero. Indeed, the study authors seem to suggest this approach as the Good One:

We suggest that instead of a single, large protein-rich meal, ingestion of multiple moderate-sized servings of high-quality protein-rich foods over the course of a day may represent an effective means of optimizing the potential for muscle growth while permitting greater con- trol over total energy and nutrient intake.

Full Disclosure: What the authors do not say is what the minimal times are between feedings such that one can make use of that full 30 again. They do state that the "post-ingestion period" is three hours. They did not however retest meal ingestion at that time to see what would happen with another dose. And that's fine for this study that was looking at size of dose for max possible effect, but it does mean we're speculating about repeats - grounded speculation, but still less tested.

Though there is a 2007 8 week trial that shows that lean mass didn't change to any statistically significant degree, whether people got all their daily protein in one meal or three a day. Whether folks were training or not was not considered. So the question comes up: are acute responses (measures taken at time of ingestion) related to longitudinal responses?

And what if Less is More? May be time to highlight again that we're talking about protein synthesis here, not protein absorption. Absorption amounts (2-2.5g/kg body weight) may be greater than required amounts for protein synthesis. An interesting question still kinda out there is if 30g is the max for resting muscle for a more or less 80kg person, what's the least amount to still get this max effect?

What about Work Outs? Things get really interesting if we consider pre and post training nutrition with carb/protein periworkout nutrition, as in this study where participants were fed slightly more than 30g protein pre AND post workouts (along with creatine and carbs). These researchers didn't test the amounts of protein they used (related work in this 2009 study suggests it's 20g post workout - thanks Kevin Greer for the ref); they just looked at whether there was a better effect with pre and post supplementation than not. They did sorta hit the maximal usable amount, which is cool, but it might be too much too soon to be fully absorbable for muscle synthesis.

Or maybe - maybe - the effect was from the Creatine and Carbs + Protein and not just the protein (another few views on protein+ creatine vs carbs + creatine [one] or pro+cho vs pro+cho+cr[another]). Dang.

Questions? What happens if we OD on protein? Can we? We know that if we're in caloric deficit, protein is getting oxidized for fuel before going to protein synthesis, right? And likewise if we eat too much of it, it gets deaminiated and the amonia gets peed out, which has been a concern/question regarding toxicity of overdoing protein:

High protein diets on the other hand advocate excessive levels of protein intake on the order of 200 to 400 g/d, which can equate to levels of approximately 5 g · kg^-1 · d^-1, which may exceed the liver’s capacity to convert excess nitrogen to urea. Dangers of excessive protein, defined as when protein constitutes > 35% of total energy intake, include hyperaminoacidemia, hyperammonemia, hyperinsulinemia nausea, diarrhea, and even death (the “rabbit starvation syndrome”[link added -mc]).

Hence the 2-2.5g/kg recommendation. Other excess ingestion of protein has protein used for glucose conversion, and we know if we don't need all the available sugar, well heck, it's stored as fat.

Summing Up?
What do we know from this study: that measured over three ours post ingestion, it doesn't matter whether an 80kg person eats 30g or three times that, that 30g of whole protein was the most that could be utilized for muscle protein synthesis in their resting muscle at a feeding.

What the authors are NOT saying: 30g of protein is needed every 2-3 hours for muscle growth. It seems kinda the opposite: less protein may be needed for acute muscle protein synthesis.

Where we mayn't be able to Generalize: While the authors suggest therefore that a strategy is to spread protein intake over the day, the 1 meal a day vs 3 meals a day study suggests that lean mass holds over time whether following this strategy or not. SO why spread out protein uptake??

If we move from protein synthesis at rest to muscle building, other work seems to suggest that even when working out that (a) just working out and (b) creatine may be more important for packing on muscle than protein. This latter point is one that Eat STop Eat author Brad Pilon makes in his ebook How Much Protein (thanks to Chris Highcock for pointing this book out to me).

So what can we say? well, what the authors also say is of note is that there's been concern that elderly eating low protein diets, mixed with other nutrients may have a blunted protein synthesis. This study suggests that there's no age related effect of upping protein to a certain point, regardless of age. Ok. So both elderly and younger types respond the same to acute protein intake when just eating protein. Good to know.

But once again a lovely finding of an acute response and a seeming logical conclusion (spread protein out over the day) doesn't seem to hold on its own in the larger context as a prescription for action. We may find though that benefits of protein supplementation have other functions than just mass related - like recovery and immune function. More food for future thought.

dang.

Related Posts

select citations
Bilsborough S, & Mann N (2006). A review of issues of dietary protein intake in humans. International journal of sport nutrition and exercise metabolism, 16 (2), 129-52 PMID: 16779921

Symons, T., Sheffield-Moore, M., Wolfe, R., & Paddon-Jones, D. (2009). A Moderate Serving of High-Quality Protein Maximally Stimulates Skeletal Muscle Protein Synthesis in Young and Elderly Subjects Journal of the American Dietetic Association, 109 (9), 1582-1586 DOI: 10.1016/j.jada.2009.06.369

CARLSON, O., MARTIN, B., STOTE, K., GOLDEN, E., MAUDSLEY, S., NAJJAR, S., FERRUCCI, L., INGRAM, D., LONGO, D., & RUMPLER, W. (2007). Impact of reduced meal frequency without caloric restriction on glucose regulation in healthy, normal-weight middle-aged men and women Metabolism, 56 (12), 1729-1734 DOI: 10.1016/j.metabol.2007.07.018

Cuthbertson, D. (2004). Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle The FASEB Journal DOI: 10.1096/fj.04-2640fje

KERKSICK, C., RASMUSSEN, C., LANCASTER, S., STARKS, M., SMITH, P., MELTON, C., GREENWOOD, M., ALMADA, A., & KREIDER, R. (2007). Impact of differing protein sources and a creatine containing nutritional formula after 12 weeks of resistance training Nutrition, 23 (9), 647-656 DOI: 10.1016/j.nut.2007.06.015 Follow @begin2dig

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Sunday, February 21, 2010

begin2dig joins the 21st century: facebook and twitter

Saturday, February 20, 2010

Improving Longevity with Calorie Reduction in Humans?

Friday, February 19, 2010

8lbs of Lean Mass in One Workout - and other surprises Feb 24 - from brad pilon

Curb my protein enthusiasm: single factor thinking fails again

Thursday, February 18, 2010

30g of protein per meal for optimal muscle building? That Depends - a lot

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