Always ~ teaser. Details on my previous statements after having checked.

I confirm that my 'reasonable' values are based upon the histogram (non parametric distribution) and not the lognormal. They rule out the tails of the parametric distribution, that is the extreme behaviours.
reasonable LB= 70 mgN-kg-1d-1 = 0.44 g kg-1 d-1
reasonable UB= 160 mgN-kg-1d-1 = 1.0 g kg-1 d-1

My previous estimate was that 90% of the data are included within those bounds, now, how many exactly?
n=235, The number of values outside the range, counting the number of values each bin = 25 (pls check my calcs if possible).

25/235= 0.11 = 11% , hence 100%-11%= 89%, practically equal to my previous quick-look estimate of 90% .

Again, table one uses a parametric model, based on the lognormal distribution fitted upon the non histogram. So the range here is more restricted than the histogram range.

If we use the lognormal distribution as reference, my statement , answerign to mushymindy, should be rewritten like this:


And I absolutely agree that using the lognormal would be a benefit sicne we have a narrower range, hence a more precise determination.
continues next.

More recent review of suggestions to the OP, mushymind, after the comments from teaser.
Pls also note that in my previous calculations I entered an ideal weight of 55.7 instead of 57.5 (rigth number) I have corrected that in my calc sheets. the mistake did nto affect much the output though.

we are now going to use the lognormal WHO distribution with the percentiles of requirements indicated in table 1. As a lower bound we may use 2.5% (83 mgN), upper bound 97.5% (133 mgN). This rules out the bilateral 5% population extremes or +- 2SD from the mean. The revised answer to mushymindy, reasoning on the parametric distribution:




Such a range is more useful since more narrow, but does not yield absolute certainty according to the WHO, 2002 data.

No significant exercise, no pregnancy, no lactation assumed.

Next development in this thread I think might be to look for some more specific populations, that is studies on samples from populations eating a low carbs diet. I don't know if there are any.

This is interesting: strenght athletes do not need those many proteins more than general propulation. An example of improved utilization from teh body when needed.

An example on how views can differ. I'd be curious to see the dataset and the rationale, if they are suggesting a minimum requirement or a safe requirement. According to Dr. rosedale, the requirements for sarcopenia are estimated in high-carb individuals, where bone proteins are preferentially burned. Low carbers would not suffer such a condition.

With muscle, my understanding is that in one sense, working out will decrease the requirement--it will take less protein to be in nitrogen balance. But eating above this requirement may be necessary if you are increasing muscle mass--the amount of protein you can benefit from by muscle growth goes up, not necessarily the maintenance requirement. Heavier exercise that blows through a lot of calories can increase the protein requirement due to increases in protein catabolism. Brad Pilon at EATSTOPEAT has suggested that it's possible that say if you ate X amount of protein, and grew this much faster than if you ate 3/4's of that, you might just plateau sooner, you might just end up in the same place anyways, and just take a bit longer.

After about 1 hour of google search I found no more specific reference. Besides, the WHO 2002 study appears to be the reference used by official agencies with minor variations.

Next development at this point, unless you guys can fidn something else, would be to examine the dataset at table 8 , page 107 of the WHO report.

At a quick look, it appears that the dataset is biased toward younger individuals and male individuals.
Diets are varied and sure usually different from LC.

Are the results drawn for a max 30 years old population valid for older guys? Many datasets contain 18 years old individuals.

I don't know what a possible correction would be for older people. Maybe nothing proably no greter need, maybe less.

So far, that's the best data available and they say basically that minimum protein requirements are pretty low and that there is a wide individual variability in the requirements.

If we want be sure that we eat no less proteins than suggested that's easy, but if we want to be sure that we eat the zero-nitrogen balance (optimum) amount that's not easy at all. The safe quantity strategy may not be compatible with the mTOR inactivation strategy (longevity).

The procedure adopted in previous posts is the best that I can come up with right now. It would be very good to have ways to determine the zero-balance points for each different person.

Yes, that's an interesting and maybe counterintuitive point, although it makes some sense that muscles when in exercise becoem more efficient in feeding themselves.

Muscle growth definitely needs more proteins, probably not the huge amounts some bodybuilders gulp down but many anyway. Also, many proteins will definitely will activate mTOR with its anabolic effect.

Professional bodybuilding is not very compatible with health and longevity. Especially so if we consider the amount sof steroids and other hormones they use.

So I have a philosophical disagreement with this approach in general. I know that if one wants to make evidence based decisions that statistics helps. It's turns data into facts. Data is ambiguous. Facts are clear. I get that. Unfortunately when applied to humans, saning the outliers should never be done. It's wrong in principle. We are all outliers. (Each in our own special way?)

Policy people hate it when I say things like that. I know. Been there, done that, got the T-shirt. "I don't have time to understand all that...." "You aren't explaining it well...." "You're not really helping" "So what all that comes down to is this....., right?" "Well we have to do something......" or my favorite, "I had to simplify it." which is the worst because they understood the detail and deliberately dumbed it down. Doesn't say much for decision makers when their best people think they have to dumb things down for them, right?

So if we are not going to take a statistical approach, if we don't care what the mean and the variance are because we know we are more likely to be outside of +/- 1 sigma rather than in it (too often the case, seriously) then what do we do? Well we can look at the symptoms of insufficient protein like cracking nails, hair falling out, muscle weakness, lasting soreness after exercise, etc. etc. We can also up our protein intake with protein shakes, etc. and see if it has a positive effect. I think that's a better approach.

Everyone has agendas. No one pays for a study who doesn't want to do something with it. My guess is that they just wanted to know how many beans to fly into the next starving country.


Many exercise and nutrition studies are based on Olympic level athletes.


We agree 100%.

Really, the issue of the outliers has always been a tricky one. In the Who's study the histogram includes all data (individuals), whereas we may say that the long RHS tail of the lognormal is representative of those extremes events (extreme need of proteins). Are those extreme representative of the biological laws governing minimum proteins requirement or not. If not, they might be analysed with the statistics of extreme events, used in the meteorological sciences and many other fields.

There is another crucial issue.
If our target is to be safe from negative nitrogen balance, that is not to eat less than the minimum probabilistic requirement, then it's enough to eat the 100% percentile, that is what the RHS outliers eat. Easy solution.
On the contrary, if we assume that too much protein can have adverse effects, and there is a desirable value to target, for example to keep the mTOR pathway inhibited, then we cannot use the safest strategy and must try to determine our own individual requirement.

Are these guys right??? I have no access to the complete paper

I have my doubts now. An n=8 study, with individuals fed not real food but a crystalline aminoacids mixture. Very arguable applicability to real life. The WHo study is n=235 and real food.

Probably 1-1/2 - 2 grams of protein per kg of lean body mass is the going rate. Age and activity level are factors with both of these on the higher end of protein consumption.