Competing goals of mild CR / protein restriction vs muscle mass / strength / activity

[sirtuin]

I have a BMI ~20 at 5'10" / 140lbs.  My body fat percentage is possibly as low as 8%?  As far as I can tell with rough tracking on cronometer, my current caloric intake is around 1900-2100kcal -- Right now, I exercise for around 30-45m 3-4x a week, although, I would like to increase this as the weather improves, which will likely require more calories.

 

I like the idea of practicing mild caloric restriction and protein / methionine restriction.  However, I would also like to gain some muscle mass, or at least maintain a high level of lean mass.  I'm not particularly active, so I wouldn't want to drop activity lower.  Is there a way to balance these competing goals of mild CR / protein restriction vs gaining muscle mass / strength & staying physically active (perhaps eating lower protein / calories most days, and higher calories / protein on exercise days?)

 

What sort of protein intake (grams) / caloric intake does the average CR practitioner consume?  Gaining muscle mass seems to require eating at a caloric surplus with a high quantity of protein and it seems like eating fewer calories would drop body fat even lower, where I don't have too much to burn there.

 

If I have a low body fat percentage at a 2,000kcal intake, am I already practicing caloric restriction for my activity level?

[GenGenimney]

I'm sorta doing the same thing (as a chick).

 

Methionine is much more concentrated in animal proteins, so I'm keeping these <7% per day based on an epidemiological survey of longevity/animal protein levels.  There's also much more in flesh than in dairy.  I'm also supplementing with glycine.  The rest is plant proteins, which have much less methionine, mostly beans/legumes/pulses and nuts/seeds.  

 

The recommendations of protein for body builders as high as a gram per pound are unfounded.  I did some digging and found that you're EASILY getting enough protein at .5g per pound of lean body mass even if your activity level is high and you're building muscle.  So that's only 65g of protein that you'd need per day.  65*4=260 calories from protein, 260/2000 = 13% protein, which means you'd want only 45 from animal sources, at most.  :)  That's pretty easy!

 

As for the last...I think I'd look at the various markers, and if they're consistent with CR, then you're CR....  It's really the only thing that makes sense to me of the various thoughts/approaches.

 

IGF is a big one, but I'm new and don't know how to interpret them.  

 

Also, if your body temp has dropped.

[sirtuin]

I found this:

https://en.wikipedia.org/wiki/Calorie_restriction

 

The authors of a 2007 review of the CR literature warned that "t is possible that even moderate calorie restriction may be harmful in specific patient populations, such as lean persons who have minimal amounts of body fat."

 

I'm curious if this applies to those with a normal BMI, but with low amounts of body fat?  It doesn't sound too beneficial / useful to me to put on more body fat and then restrict calories and protein (that doesn't sound like a healthier / aesthetic body type?)

 

To gain muscle, it seems like you would still need to eat above a calorie-restricted diet, probably more ideally at some surplus of calories (while protein intake might be able to stay a bit lower than optimal for muscle-building purposes).  I'm curious how something like 3months of CR / 1mo of intermittent fasting + eating above caloric maintenance (or a smaller cycle?) with extra (non-methionine heavy) protein while eating to add muscle might work to compromise between these opposing goals.

 

BCAA's + high-GI carbs might help to avoid methionine / cysteine while adding muscle, but also considerably raises IGF.  Or, perhaps it's best to just pick one goal.

 

For measuring body temp, do you just use a thermometer?  I do find myself feeling a bit more cold in the winter, but, it's over 100 degrees outside and fairly warm in the house these days.  What are other (cheap) markers to measure?

[GenGenimney]

Well, CR is going to be harmful to ANYONE below a certain threshold.

 

Deficits don't last forever.  So if you're at a set point that's in the CR range, then lowering your intake more and creating a new deficit could push you past the benefit zone into a starvation status.  Starving ain't good.

 

The HUUUUUUUGE question is...CR based on what normal?

 

I have a sneaky little suspicion here, given that rats don't get medical intervention the way people do, that the normal lifespan of humans is probably about 75-80 years, while CR can boost the outside to 105 or so.  The differences are more modest than in mice, but since they already age so quickly, that's to be expected.  We don't get pretty little graphs of CR versus controls in the wider population because there is no true, clear control--we have everything from substance abuse of various sorts to tremendously bad diets to good diets but too much confounding everything.  

 

But I think there are people walking around right now with CR-consistent blood work, BPs, arteries, and RHRs who have no idea that they're doing anything special.  I had that for YEARS.  I'd heard of CR (because I hear of a lot of things) but never imagined that I'd be in it.  My BF% ranged from 10%-16% in that time (again, woman here, higher numbers).  I had a low-protein diet, but it was pretty high on refined carbs.  (I was an 80s kid, what can I say?)  I've never been below a BMI of 18.5 as a teen or adult.  I was was normal weight/lean.

 

I've measured body temp--I'm using a thermometer that corrects to 98.6, but it still gives the right temp-below-normal from that--resting heart rate and blood pressure so far.  Once my blood pressure is down to 90/60 or below consistently and my RHR (I'm a woman, so mine runs higher) is below 50, I'll be in the zone as far as that's concerned.  Some people are looking at fasting and post-prandial glucose, too, so I grabbed a $10 kit.  I have NO idea what I'm looking for there, though.  LOL.

 

Subjectively, I feel hot, sweaty, and miserable all the time with "normal" temperature.  Now that it's dropped a little again, I'm more comfortable.  When it's quite low, I'm slightly cold at temperatures other people like, so I always used to bring a coat everywhere.  I adapted weirdly well to working in high-temperature conditions.  As an engineering intern at a paper mill (floor temps vary from 90/95 degrees in the ware house to around 120 in the basement where all the pipes are), I didn't sweat at all on the floor after a couple of weeks and only got hot in the basement.  I wore a winter coat in the labs and the offices, though, and I took any work I could out in the factory.  Everyone there thought I was a bit of a freak for it.  People who had worked there 20, 30 years were red-faced and fled back into their climate-controlled viewing rooms.  And I was actually comfortable.  At home, I had my AC set to 85, and visitors thought it was broken.  At that time, I had a BF% of about 10%.

 

I ran to the mill's clinic once because I slashed my finger on my mailbox on my way into work one morning, and the nurse just about FLIPPED OUT at my body temperature--it was 96.8 orally.  He wanted me to get checked out at the hospital.

 

I do exercise quite a bit.  I walk on a treadmill when I work and do 1hr-1:15 of exercise 6 days a week.

 

I'm personally VERY concerned about osteoporosis.  Both of my grandmothers died from complications of conditions caused by osteoporosis.  So I want a baseline DEXA scan, and I won't restrict to the point that my menstruation stops (though I've always been on a looooong cycle).

 

Significant to protein:  Post-menopausal women are protected by higher levels of protein, specifically plant protein, from osteoporosis.  Both men and women have longer lifespans with lower protein before 65 years of age and higher protein after.

[BrianMDelaney]

I have a sneaky little suspicion here, given that rats don't get medical intervention the way people do, that the normal lifespan of humans is probably about 75-80 years, while CR can boost the outside to 105 or so.

 

Lots to respond to here (and in other threads...), but I just want to note that that claim is one I've been making for years as an answer to the CR-skeptical objection: "If CR works in humans why haven't we ever seen a human live to 160, or 150, or 130, or even 125?!?! Among the billions of humans who've existed, surely there've been cases of 'accidental CR'!!" Well, we have seen lots of accidental CR (the tiny fraction of cases of food restriction that are of a high enough quality to slow aging safely).

 

I think the normal non-CR (ad libitum but not pigging out) lifespan of the healthiest, most longevous "strain" of humans is probably 95-100-ish. People living longer have been on some version of CR. You'd really have to look at different "strains" to make the case, of course.

 

But the implications might matter during this epoch when we don't have really good biomarkers of degree of CR. In the meantime (as you note): things like low IGF1, good fasting blood glucose, etc. are the best not too complicated/not too expensive markers we have available. A lot of people just look at biomarkers of diseases associated with aging.

 

 

 

The recommendations of protein for body builders as high as a gram per pound are unfounded.  I did some digging and found that you're EASILY getting enough protein at .5g per pound of lean body mass even if your activity level is high and you're building muscle.

 

Do you happen to have a reference for that handy?

 

Brian

[James Cain]

As for the last...I think I'd look at the various markers, and if they're consistent with CR, then you're CR....  It's really the only thing that makes sense to me of the various thoughts/approaches.

 

Gen, thanks for the thorough response. I think your summary and approach to CR is spot-on. Same with Brian's response, and I too am interested in the protein reference. I know protein can be fairly low (at least a lot lower than many people think) and be adequate for most people, but there are some caveats.

 

I found this:

https://en.wikipedia.org/wiki/Calorie_restriction

 

The authors of a 2007 review of the CR literature warned that "t is possible that even moderate calorie restriction may be harmful in specific patient populations, such as lean persons who have minimal amounts of body fat."

 

I'm curious if this applies to those with a normal BMI, but with low amounts of body fat?  It doesn't sound too beneficial / useful to me to put on more body fat and then restrict calories and protein (that doesn't sound like a healthier / aesthetic body type?)

 

[Note: to save time I copy/pasted much of this with minor edits from my recent post in the CRS Facebook group, but I think it (mostly) applies here.]

 

CR is a very interesting phenomenon when observed in non-homogenous populations. At its most basic level, CRON is about achieving a unique physiological state through restricting calories usually 10-30% below the intake that would keep you weight stable at a (presumably) normal weight. If you begin CR with more mass and a higher calorie intake then this number will be higher than someone who is smaller and consuming less calories to maintain their normal weight.

 

Ultimately, assuming ON is met, CR is primarily about never quite topping off the cell's fuel tank and stimulating a mild stress response based on energy sensing pathways, and a secondary (but probably less important) about simply consuming less overall and putting less stress on the body with regards to overall processing of nutrients, toxins, etc. This second part is difficult to define and quantify with research, but there very well may be a benefit for being smaller and consuming less calories (and overall food independent of calories, due to potential toxins in those foods such as pesticides, AGEs, etc.). This implies more benefit for a given %CR in the smaller individual, meaning 10% CR requiring 1700 kcal/day would be better than 10% CR requiring 2000 kcal/day. The first principle of CR--never topping off the cells fuel tank--leads to known physiological responses and biomarkers. These would be similar similar between both practitioners of CR (smaller vs. larger body mass and calorie intake) assuming each were restricted to the same relative %CR. 

 

My point here is that in outliers such as those with significantly more muscle mass or leanness, achieving CR and the relevant biomarkers may not look like "CR" in an average person. For example, I used to be 250 lbs at 10% body fat and consuming 7000 kcal/day to maintain my weight. I currently sit at 180-182 lbs 7% body fat consuming 2300-2500 kcal/day. For the most part, I've slowly reduced my calorie intake to maintain biomarkers indicative of mild-moderate CR over the past 5-7 years. My body weight initially dropped rapidly but stabilized and only very slowly drops (if at all) at this point.

 

This is in part due to my relatively high physical activity and moderate approach to CR, but partly because I've reached a certain metabolic efficiency beyond which (even by 100-200 kcal/day) I get symptoms of excessive restriction. Symptoms of excessive restriction include lethargy, cognitive decline, mood disorders (mostly depression), disrupted sleep, excessively poor wound healing, mental fixation on food beyond a reasonable level. Many long-term CR practitioners report similar, though most are at a lower body mass and require 1700-2000 kcal/day. The point is that I eat to achieve biomarkers based on the principles of CR I outlined above, and these are related but at least partially independent of body weight.

 

Here are my recent numbers to put this in perspective:

Anthropometry

6'3", 182 lbs, BMI 22.7, 7% body fat [started at 250 lbs, 10% body fat, BMI 31.2]

 

Biomarkers

Body temp--97.0-97.5 F

Blood pressure--105/65

WBC count--3.2 (range 3.7-10.1)

Lipids--Chol (134), HDL-C (38) LDL-C (81), LDL-P (867), TAG (76)

Fasting glucose--77

Fasting insulin--2.9 (range 2.6-24.9 uUI/mL)

IFG-1--126 (range 98-282 ng/mL)

 

I have no doubt that over time I will continue to lose muscle mass, though I seem interestingly stable with my body weight since reaching 190-182. I do plan to modify my intake and exercise to reduce my body weight to at least 160 lbs in order to simply carry less body mass--I had hip surgery and some potential for impact-induced degeneration of my hip and lower back over time. I'm curious to see where this takes me consider the above.

 

Of additional consideration, research shows that excessive exercise requiring additional calorie intake offsets some of the unique metabolic effects of CR, but CR without exercise proves detrimental to physical function, and maximum longevity and healthspan are achieved through CR with at least some exercise or regular physical activity. A great example of this is that marathon runners maintain similar BMI and leanness as CR practitioners but don't experience the same CR benefits. However, the real question is about someone who can maintain a certain leanness or muscle mass while achieving CR biomarkers. Some cronies exercise quite a bit, and some maintain a higher mass than others, and I wonder if there is a true 'optimum' for everyone or for individuals that we can determine. There are all sorts of studies on this that could be put into a sort of 'position statement' on CR, exercise, and anthropometric profiles.

[kpfleger]

Sorry to be late to this conversation, but it's a topic I care a bit about, and some folks here asked for refs. Maybe these might help a bit. Some former colleagues and I have a group that discusses diet's effects on health. The group is mainly vegans who follow prominent vegan nutrition experts like Fuhrman, McDougall, etc. plus a couple low-carb/paleo types, but not mainly CR folks. We previously discussed protein requirements and tradeoffs and dug up several links. FWIW.

 

My high level sense is that there is a fundamental tradeoff between building muscle and certain other long-term health optimizations. Certainly, one wants to not lose too much cardiac muscle, so that's an area where things may be aligned, but my sense is that in the long-run, cardiovascular disease is easier to avoid with lifestyle than cancer and optimal cancer prevention probably does mean lower protein consumption than is optimal for building athletic muscle.

 

Excerpts/notes from the old conversation (from 2014):

 

A prominent vegan doctor defends low-protein (but might be exaggerating a bit to the low side, see below):

http://www.drmcdougall.com/misc/2007nl/apr/protein.htm

Notes: The WHO recommends 5% of their calories as protein (38g for 3000 calories).

Human milk is 5% protein. Rice is 8% protein. Most other grains & veggies are more.

 

-----

 

Examples of protein science focused on athletic performance rather than health/longevity:

 

2nd result for Google query [protein requirements exercise]:

Int J Sport Nutr.

 1998 Dec;8(4):426-47.

Effects of exercise on dietary protein requirements.

"...recent evidence suggests that dietary protein need increases with rigorous physical exercise. Those involved in strength training might need to consume as much as 1.6 to 1.7 g protein x kg(-1) x day(-1) (approximately twice the current RDA) while those undergoing endurance training might need about 1.2 to 1.6 g x kg(-1) x day(-1) (approximately 1.5 times the current RDA). Future longitudinal studies are needed to confirm these recommendations and asses whether these protein intakes can enhance exercise performance. Despite the frequently expressed concern about adverse effects of high protein intake, there is no evidence that protein intakes in the range suggested will have adverse effects in healthy individuals."

 

2nd result for [protein requirements athletes] claims to summarize many science articles:

http://www.bodyrecomposition.com/muscle-gain/protein-requirements-for-strength-and-power-athletes.html

 

Besides protein quantity, timing is another issue, with some (eg Fuhrman) advocating exercise after fasting (for lower inflammation & reduced pro-cancer effects of exercise) but some performance literature suggesting protein consumption before exercise. Eg, “Acute and Long-term effects of resistance exercise with or without protein ingestion on muscle hypertrophy and gene expression” by Juha Hulmi, which concludes "protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy."

 

I'm no expert in this area, but I think these give a sense of the athletically-inclined science even if they are somewhat randomly pulled examples.

 

----

 

It's interesting that different mammals have such different breast-milks. Human breast-milk is only 5% protein by calories, but cows milk is much higher 20 or 30% IIRC (which is probably why the 5% number is so surprising). The higher proportion for cows sounds intuitive since cows have to grow so large, but one page I read said rabbits' milk is also much higher than humans. I didn't trace that down to see if it was right, but if so, it would be interesting to understand why different mammals have such different milks. Maybe rabbits have to grow much faster than people even if their final size is smaller?

 

-----

 

This 5% of calories from protein recommendation from McDougall's page seems questionable. Higher seems to be the standard recommendation from other authoritative, trustworthy sources...

 

I tried 2 very basic searches: A: [protein RDA] and B: [protein recommendations] on Google:

 

1st result for A (& 2nd for B) was a basic CDC protein info page that said "it's recommended that 10–35% of your daily calories come from protein" and also said that the RDA for male adults 19-70+ is 56g. The footnote there cites "Dietary Reference Intakes for Energy, Carbohydrate. Fiber,Fat, Fatty Acids,Cholesterol, Protein, and Amino Acids (2002/2005)" from the Institute of Medicine. This PDF file seems to be a summary of their numbers and explains that "Acceptable Macronutrient Distribution Range (AMDR) a [the 10-35% of calories range] is the range of intake for a particular energy source that is associated with reduced risk of chronic disease while providing intakes of essential nutrients. If an individuals consumed in excess of the AMDR, there is a potential of increasing the risk of chronic diseases and insufficient intakes of essential nutrients." But I haven't tried to read this whole report. Another result from the search where I turned up the PDF file was a WikiAnswers page that claimed: "Below this range risks reduced healing, immune system function, and in severe cases a disease called kwashiorkor."

 

[For those like me who didn't know: "The Institute of Medicine (IOM) is an independent, nonprofit organization that works outside of government to provide unbiased and authoritative advice to decision makers and the public. Established in 1970, the IOM is the health arm of the National Academy of Sciences.]

 

The 2nd result for query A (& 1st for B) was a webmd.com page that repeated the same 56g and 10-35% numbers with the same source. The next several results for both queries repeat the above numbers. Then we get to results that point out increased needs if one exercises. This page from Mens Health [result 5 & 4 respectively] suggests higher numbers than the 56g/day for those who exercise, citing Donald Layman PhD, a professor emeritus of nutrition at the University of Illinois and Mark Tarnopolsky MD PhD, who studies exercise and nutrition at McMaster University in Ontario. This about.com page [result 6 for both queries] says 0.8g/kg of body weight (which works out to about the 55g for a 150lb person, matching the previous suggestion) for a sedentary person, but up to 1.8g/kg "if you are under stress, are pregnant, are recovering from an illness, or if you are involved in consistent and intense weight or endurance training". The upper end of that rec (1.8) works out to ~123g/day.

 

Result 7 from query A, a PCRM page, seems to be the only page in these 20 that warns against too much protein and implies that less than the 56g RDA might be good for a large fraction of people. But even this page starts off with the same RDA numbers as above and does not mention the WHO or anything like a 5% of calories number. None of the results in the top 10 for either query seem to mention the WHO or any number as low as 5% of calories.

 

Querying specifically for the WHO recommendation, it's hard to quickly find their recommended number. [protein rda OR recommendation who OR "world health organization"]'s result 1, the seemingly correct page at the correct website shows no rec but links to a page with a long list of publications of various requirements, that if you find-in-page for protein shows a 2007 report whose page doesn't give any abstract or punchline but lets you download the full 250+ page PDF. Looking through the table of contents leads to the "summary of protein requirement values for adults..." section on page 125 which says: "the safe level was identified as the 97.5th percentile of the population distribution of requirement, [...] 0.83 g/kg per day protein would be expected to meet the requirements of most (97.5%) of the healthy adult population." That's the same ~56g/day number above for a 150lb adult, and seems quite a bit higher than the 38g number from McDougall. The table on page 87 of the 250-page PDF is maybe McDougall's source (per my friend who figured that out). The report has interesting discussions of many aspects of protein consumption, including dismissals of many too-much-protein concerns. 

 

-----

 

One sense I come away with is that this is another area where tweaking or arguing about population level recommendations becomes more and more pointless after a while. Rather what we need are better understandings of all the most common things that go wrong with too little and with too much, along with better diagnostic tests (and lots of data to calibrate them) to identify when any of those things start happening.

 

-Karl

[kpfleger]

PS Is there some global setting an admin can change so that the 2nd letter of the alphabet doesn't get auto-turned into an annoying emoticon whenever it's next to a paren?

[AlPater]

The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption.
van Vliet S, Burd NA, van Loon LJ.
J Nutr. 2015 Sep;145(9):1981-91. doi: 10.3945/jn.114.204305. Epub 2015 Jul 29. Review.
PMID:26224750
http://arc.crsociety.org/read.php?3,224627,224627#msg-224627

Abstract

Clinical and consumer market interest is increasingly directed toward the use of plant-based proteins as dietary components aimed at preserving or increasing skeletal muscle mass. However, recent evidence suggests that the ingestion of the plant-based proteins in soy and wheat results in a lower muscle protein synthetic response when compared with several animal-based proteins. The possible lower anabolic properties of plant-based protein sources may be attributed to the lower digestibility of plant-based sources, in addition to greater splanchnic extraction and subsequent urea synthesis of plant protein–derived amino acids compared with animal-based proteins. The latter may be related to the relative lack of specific essential amino acids in plant- as opposed to animal-based proteins. Furthermore, most plant proteins have a relatively low leucine content, which may further reduce their anabolic properties when compared with animal proteins. However, few studies have actually assessed the postprandial muscle protein synthetic response to the ingestion of plant proteins, with soy and wheat protein being the primary sources studied. Despite the proposed lower anabolic properties of plant vs. animal proteins, various strategies may be applied to augment the anabolic properties of plant proteins. These may include the following: 1) fortification of plant-based protein sources with the amino acids methionine, lysine, and/or leucine; 2) selective breeding of plant sources to improve amino acid profiles; 3) consumption of greater amounts of plant-based protein sources; or 4) ingesting multiple protein sources to provide a more balanced amino acid profile. However, the efficacy of such dietary strategies on postprandial muscle protein synthesis remains to be studied. Future research comparing the anabolic properties of a variety of plant-based proteins should define the preferred protein sources to be used in nutritional interventions to support skeletal muscle mass gain or maintenance in both healthy and clinical populations.

[Michael R]

All:
 

Some former colleagues and I have a group that discusses diet's effects on health. The group is mainly vegans who follow prominent vegan nutrition experts like Fuhrman, McDougall, etc. plus a couple low-carb/paleo types, but not mainly CR folks.

That must be an interesting mix!
 

Certainly, one wants to not lose too much cardiac muscle

To the extent that it translates, in the rodents, CR is somewhat sparing of heart muscle: 71% of mass maintained under 40% CR, vs. 58% of the total body weight and only 30% of the adipose. (See here ; from (1)). Also, a lighter organism has less need for heart muscle to pump blood; ditto for an organism with the blood pressure of a ten-year-old; and CR is known to quite dramatically reduce the fibrosis, cardiomyopathy, and other structural and functional pathology of the aging heart — in mice.

cardiovascular disease is easier to avoid with lifestyle than cancer and optimal cancer prevention probably does mean lower protein consumption than is optimal for building athletic muscle.

True as far as it goes, but the form of "cardiovascular disease" of which it's easy to substantially reduce one's risk (atherosclerosis) is really not related to the heart muscle itself. To the extent that one might worry about a reduction in cardiac muscle, this isn't a relevant item in the calculus (aside, again, from having CR-like super-low BP).
 

A prominent vegan doctor defends low-protein (but might be exaggerating a bit to the low side, see below):
http://www.drmcdougall.com/misc/2007nl/apr/protein.htm
Notes: The WHO recommends 5% of their calories as protein (38g for 3000 calories).

McDougall is not an honest player in the nutrition space. If WHO ever really did recommend this little protein, they definitely don't now:
 

8. SUMMARY OF REQUIREMENTS FOR ENERGY AND PROTEIN
... For adults the protein requirement per kg body weight is considered to be the same for both sexes at all ages and body weights within the acceptable range. The value accepted for the safe level of intake is 0.75 g per kg per day, in terms of proteins with the digestibility of milk or egg.

My emphasis. This is roughly in line with the IOM's protein RDA. And note the caveat of "highly-digestible" proteins. IOM is even more specific, highlighting "high-quality" proteins — ie, more or less, animal protein. Vegetable protein is much less able to support tissue maintenance (as vs. as a source of Calories), in part because of digestibility issues (protein bound to fiber is less absorbable) and in part due to amino acid composistion. Many of these issues are discussed in this review whose abstract Al just posted:
 

The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption.
van Vliet S, Burd NA, van Loon LJ.
J Nutr. 2015 Sep;145(9):1981-91. doi: 10.3945/jn.114.204305. Epub 2015 Jul 29. Review.
PMID:26224750

I note that one of the authors has posted the full text. Surprisingly, there is nothing at all about mTOR.

 

The FAO report also reveals that the World Health Organization has abandoned the idea of metabolic adaptation to significantly lower protein intakes, an idea that they accepted and promulgated for decades.

Reference
1: Weindruch R, Sohal RS. Seminars in medicine of the Beth Israel Deaconess Medical Center. Caloric intake and aging. N Engl J Med. 1997 Oct 2;337(14):986-94. Review. PubMed PMID: 9309105; PubMed Central PMCID: PMC2851235.

[timc]

1st result for A (& 2nd for B) was a basic CDC protein info page that said "it's recommended that 10–35% of your daily calories come from protein" and also said that the RDA for male adults 19-70+ is 56g. The footnote there cites "Dietary Reference Intakes for Energy, Carbohydrate. Fiber,Fat, Fatty Acids,Cholesterol, Protein, and Amino Acids (2002/2005)" from the Institute of Medicine. This PDF file seems to be a summary of their numbers and explains that "Acceptable Macronutrient Distribution Range (AMDR) a [the 10-35% of calories range] is the range of intake for a particular energy source that is associated with reduced risk of chronic disease while providing intakes of essential nutrients. If an individuals consumed in excess of the AMDR, there is a potential of increasing the risk of chronic diseases and insufficient intakes of essential nutrients." But I haven't tried to read this whole report. Another result from the search where I turned up the PDF file was a WikiAnswers page that claimed: "Below this range risks reduced healing, immune system function, and in severe cases a disease called kwashiorkor."

 

[For those like me who didn't know: "The Institute of Medicine (IOM) is an independent, nonprofit organization that works outside of government to provide unbiased and authoritative advice to decision makers and the public. Established in 1970, the IOM is the health arm of the National Academy of Sciences.]

 

The 2nd result for query A (& 1st for B) was a webmd.com page that repeated the same 56g and 10-35% numbers with the same source. The next several results for both queries repeat the above numbers. Then we get to results that point out increased needs if one exercises. This page from Mens Health [result 5 & 4 respectively] suggests higher numbers than the 56g/day for those who exercise, citing Donald Layman PhD, a professor emeritus of nutrition at the University of Illinois and Mark Tarnopolsky MD PhD, who studies exercise and nutrition at McMaster University in Ontario. This about.com page [result 6 for both queries] says 0.8g/kg of body weight (which works out to about the 55g for a 150lb person, matching the previous suggestion) for a sedentary person, but up to 1.8g/kg "if you are under stress, are pregnant, are recovering from an illness, or if you are involved in consistent and intense weight or endurance training". The upper end of that rec (1.8) works out to ~123g/day.

 

PS Is there some global setting an admin can change so that the 2nd letter of the alphabet doesn't get auto-turned into an annoying emoticon whenever it's next to a paren?

Can you toggle the "Enable emoticons?" in "Post Options" (presently to the right)? [Click "More Reply Options" first.] It worked on your quote above and the test emoticons below. I'm not aware of a global solution or graceful way to change the default to disable.

 

Test emoticons below - not attempts to convey emotion!

 

:)

B)

;)

;0

[Michael R]

At first, I couldn't figure out why the heck Tim had re-posted nearly all of Karl's previous post: I see it was to give a clean posting of the emoticon-garbled rendering about which he was complaining.

 

Karl, a quick-and-dirty solution to this if you don't want to have to go thru' "More Reply Options" is to use a different opening and closing parenthesis — e.g. (c] and (b].

[timc]

As a dirty hack here,

 

Typing "B)" was altered to only emote if typing "B)xyz", like such

 

If there is a better idea than appending "xyz", would love to here it - maybe ";;;".

 

There ought to be another way to find where the checkbox for "Enable emoticons" is unchecked by default but that would only work for the non-quick reply editor.

 

Even "small b" "b)" isn't safe ... (I use that all the time, sob).

 

The ones like :rolleyes: still work

[Dean Pomerleau]

[Note: This is a cross post from another thread on glycine:

https://www.crsociety.org/topic/11179-glycine-and-epigenetics-of-mitochondrial-aging/?p=13401

but is relevant here because it deals with sparing muscle mass while losing weight. - Dean]

 

Back to the topic of muscle sparing on CR - Al Pater posted the following paper [1] that found (in mice) that supplementing with glycine (as opposed to l-alanine) Caused the rats to preferentially lose fat mass and retain muscle mass during relatively rapid weight loss due to CR.

 

I'm reticent about supplementing with individual amino acids, but it is something to keep in mind, particularly if replicated in humans.

 

--Dean

 

------------

[1] Clin Nutr. 2015 Sep 25. pii: S0261-5614(15)00241-1

doi: 10.1016/j.clnu.2015.08.013

 

lycine supplementation during calorie restriction accelerates fat loss and protects against further muscle loss in obese mice.

 

Caldow MK, Ham DJ, Godeassi DP, Chee A, Lynch GS, Koopman R.

 

Abstract

 

BACKGROUND & AIM:

 

Calorie restriction (CR) reduces co-morbidities associated with obesity, but also reduces lean mass thereby predisposing people to weight regain. Since we demonstrated that glycine supplementation can reduce inflammation and muscle wasting, we hypothesized that glycine supplementation during CR would preserve muscle mass in mice.

 

METHODS:

 

High-fat fed male C57BL/6 mice underwent 20 days CR (40% reduced calories) supplemented with glycine (1 g/kg/day; n = 15, GLY) or l-alanine (n = 15, ALA). Body composition and glucose tolerance were assessed and hindlimb skeletal muscles and epididymal fat were collected.

 

RESULTS:

 

Eight weeks of a high-fat diet (HFD) induced obesity and glucose intolerance. CR caused rapid weight loss (ALA: 20%, GLY: 21%, P < 0.01), reduced whole-body fat mass (ALA: 41%, GLY: 49% P < 0.01), and restored glucose tolerance to control values in ALA and GLY groups. GLY treated mice lost more whole-body fat mass (14%, p < 0.05) and epididymal fat mass (26%, P < 0.05), less lean mass (27%, P < 0.05), and had better preserved quadriceps muscle mass (4%, P < 0.01) than ALA treated mice after 20 d CR. Compared to the HFD group, pro-inflammatory genes were lower (P < 0.05), metabolic genes higher (P < 0.05) and S6 protein phosphorylation lower after CR, but not different between ALA and GLY groups. There were significant correlations between %initial fat mass (pre CR) and the mRNA expression of genes involved in inflammation (r = 0.51 to 0.68, P < 0.05), protein breakdown (r = -0.66 to -0.37, P < 0.05) and metabolism (r = -0.59 to -0.47, P < 0.05) after CR.

 

CONCLUSION:

 

Taken together, these findings suggest that glycine supplementation during CR may be beneficial for preserving muscle mass and stimulating loss of adipose tissue.

 

PMID: 26431812

[Michael R]

Back to the topic of muscle sparing on CR - Al Pater posted the following paper [1] that found (in mice) that supplementing with glycine (as opposed to l-alanine) Caused the rats to preferentially lose fat mass and retain muscle mass during relatively rapid weight loss due to CR.

 

The two quite substantial caveats are that (a) this was not CR proper, but weight loss in very obese animals with lots of fat to burn generated by dietary energy deficit, and the effects may not be the same in an animal (including H. sapiens) that starts off witht a more reasonable level of adiposity; and (b] as you say, this was very rapid weight loss, which is inappropriate for CR: the effect may be a wash if one is losing weight responsibly for CR — meaning slowly, with plenty of resistance training, and (IMO) with a relatively high-protein diet until one reaches one's intended/expected long-term stable CR weight.