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Following up on Michael Rae's comments cited here.

Calorie Restriction and Sarcopenia

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The benefits of calorie restriction have been extended into sarcopenia. In rats, a 6 week 20% reduction in calorie intake led to an attenuation of age-related loss of muscle mass and function in the soleus and gastrocnemius muscles through an upregulation of PGC-1α (Joseph et al. 2013a). Calorie restriction also preserved fibre number and type and protected mitochondrial DNA from deletion (Lee et al. 1998b). In rats, calorie restriction decreased apoptosis and protected from oxidative stress (Dirks and Leeuwenburgh 2004) as well as a decrease in the overall oxidation status in skeletal muscle (Hepple et al. 2008).

These data suggest that calorie restriction prevents sarcopenia potentially through an inhibition of apoptosis and enhancement of the mitochondrial function and this has been shown to occur through the upregulation of the NAD-deacetylase Sirt1 (Cohen et al. 2004). Sarcopenia was also attenuated by calorie restriction in the rhesus monkey (Colman et al. 2008).

[...] Importantly Mercken et al. showed a long term 30% reduction in calorie intake in humans changed the transcriptional profile in skeletal muscle of an older individual similar to that of a younger subject, increased the production of antioxidants and decreased inflammation (Mercken et al. 2013).

This suggests that the benefits of calorie restriction can be extended into human muscle however a lot more work is needed in this area. It is likely that for a high adherence and for beneficial effects of a calorie restricted diet, this would have to be implemented at a younger age and it would be vital for people to be well informed about calorie intake. This would also need to be looked at on an individual basis as insufficient nutrition is already a problem for a lot of elderly people therefore, if misinformed it could lead to the malnutrition of patients which has been shown to result in a lower muscle mass (Pierik et al. 2017).

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6223729/

 

 

 

 

Edited by Sibiriak

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Mccoy:  ... the mental benefits of the sense of well being which comes with exercise, possibly related to the production of Brain Neurotrophic Factor

Good point.    Exercise (and even better, sport, vigorous outdoor activities, dance, etc) is  great for mood and cognitive performance etc.

 

Edited by Sibiriak

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Mike, I'll show that the sentence "WE must avoid consuming too much protein" is not very clear or precise.

For, example: how much is too much?

Answer, interpreting from the Fontana book: beyond the WHO RDA of 0.8 g/kg/d, protein intake starts being too much.

That's not necessarily true, though, according to the RDA of the WHO (which is by the way applied to many nutrients).

The 0.8 value is the 97.5 percentile of the statistical distribution fo all requirements, from the study of Randd et al., 2003.

Hence, it constitutes a cautious estimate, an estimate which is already high.

The RDA itself might be, for some people, twice the amount of the minimum requirement. This may be too much protein, since for the low percentiles of minimum requirement, the statistical distribution indicates values which are really low. But they are true, if the method (nitrogen balance) and the measurements are reliable.

 

The following figure is drawn from the official WHO reference. Most people studied are all right (zero nitrogen balance) with 0.63 g/kg/d, but a few of'em are all right with 0.5 or even 0.4 g/kg/d.

So, we might argue that the RDA itself is too much protein for some people. Of course, this implies that beyond the RDA is too much protein for almost all people, barring some outliers.

A confounding factor, which has not been studied in that publication that I know, is the consumption of carbs. Many carbs seem to have a so called sparing effect of proteins. So for those who eat many carbs, the 0.8 RDA might statistically be too much. But that's not necessarily true.

So, the random aspect of the minimum protein requirements is such that the requirement is individual, varies within a large range and we really don't know where we belong in terms of the random variable (minimum requirement).

The above having been said, the only way to figure out if we are eating too many, too little, or just the right amount of protein is to experiment ourselves. And that's not an easy thing to do at all,  we might use muscle mass as a proxy of nitrogen balance and measure ourselves with a caliper on three body parts for example.

 

image.png.6f904e797c5fb422c11226054eeb7292.png

 

 

 

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11 hours ago, mccoy said:

Mike, I'll show that the sentence "WE must avoid consuming too much protein" is not very clear or precise.

For, example: how much is too much?

Answer, interpreting from the Fontana book: beyond the WHO RDA of 0.8 g/kg/d, protein intake starts being too much.

That's not necessarily true, though, according to the RDA of the WHO (which is by the way applied to many nutrients).

The 0.8 value is the 97.5 percentile of the statistical distribution fo all requirements, from the study of Randd et al., 2003.

Hence, it constitutes a cautious estimate, an estimate which is already high.

The RDA itself might be, for some people, twice the amount of the minimum requirement. This may be too much protein, since for the low percentiles of minimum requirement, the statistical distribution indicates values which are really low. But they are true, if the method (nitrogen balance) and the measurements are reliable.

 

The following figure is drawn from the official WHO reference. Most people studied are all right (zero nitrogen balance) with 0.63 g/kg/d, but a few of'em are all right with 0.5 or even 0.4 g/kg/d.

So, we might argue that the RDA itself is too much protein for some people. Of course, this implies that beyond the RDA is too much protein for almost all people, barring some outliers.

A confounding factor, which has not been studied in that publication that I know, is the consumption of carbs. Many carbs seem to have a so called sparing effect of proteins. So for those who eat many carbs, the 0.8 RDA might statistically be too much. But that's not necessarily true.

So, the random aspect of the minimum protein requirements is such that the requirement is individual, varies within a large range and we really don't know where we belong in terms of the random variable (minimum requirement).

The above having been said, the only way to figure out if we are eating too many, too little, or just the right amount of protein is to experiment ourselves. And that's not an easy thing to do at all,  we might use muscle mass as a proxy of nitrogen balance and measure ourselves with a caliper on three body parts for example.

 

image.png.6f904e797c5fb422c11226054eeb7292.png

 

 

 

MCCoy I think you think too much! LOL! IF you read the whole section on protein you will see there is no absolute wrt protein intake, but Luigi makes it pretty clear and keeps it rather simple. Eat predominantly a varied, whole plant food diet. Whole grains, nuts, legumes, fruits and veggies. Also he does not see it as a problem to eat a bit of cheese or meat just keep it light. Fatty fish a few servings a week. That’s about it. If you use that  as a guide and keep your waistline trim based on the height waist ratio your good to go! If one does this then No need to fuss about protein. 

Edited by Mike41

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Mike I agree with Fontana in making it simple, since that's a book targeted at the whole population, whereas my excessive nit-picking is coherent with the degree of orthorexia exercised  by the users of this forum. 

As you say, my impression is that Fontana is strongly against an excess of protein, which can be generally described as quantities significantly higher than the RDA. Especially so animal protein.

The fact about defining excess remains though, it may be that we are exceeding even with amounts equal to the RDA. But I agree that this concept may be dangerous. Theonly experimenting I did in regard was limiting protein to RDA-ish values and limiting carbs to 50-100 grams per day (to me that's a low carb diet).

That regime made me loose fat and muscle mass even though I was exercising, so I probably went into negative nitrogen balance.

I might not have experienced that eating more carbs, or I might have experience a maintenance of muscle mass without an increase of it.

 

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