OT: The Secrets of Sugar - the fifth estate - CBC News

[eridanus]

The Secrets of Sugar - the fifth estate - CBC News

https://www.youtube.com/watch?v=xDaYa0AB8TQ

This comments have some relation to evolution even if it is not a
common topic of conversation here.

this documentary is very interesting with anyone with a little overweight.

I personally has started a campaign to fast with the aim of loose weight
for I weighted some 190 Lb and had a problem. Not only I was feeling
hungry all day, and eating little amounts of milk and some little biscuits.

Then, the most I ate the more hunger I was feeling. Then, I thought,
I have a problem. So, I thought the situation was absurd. Not only I was
feeling hunger, I even felt sleepy after eating have a tea cup of milk
with two or three thing biscuits low in fat. Then, I recalled the case
of some experiments in which the rat that eat too much was most of the time
sleeping, while the rat that was famelic while the rat on a diet of
being thin, was mostly hungry and was restless; it do not stopped moving
like it was looking for some food. This image bring me to the case of
a hunter gatherer that gets a little fat during the months of abundance
food and after them the food gets scarce, and they had to move their ass
faster to find new sources of food to keep going. And with an empty belly
and some fat around the belly, this primitive man could be able to move
his ass to look for food each morning.

I started at the start of this month to fast and I had lose already
7 kilos (15.5lbs) I had calculated that 1 kilo of fat contains some
80% water and the rest is almost fat; then 200 gr. of fat is some 1800
Kilocalories or 7524 KJoules. This almost the energy consumed by a
man of my age that is doing very little exercise.
Then, in some 19 days I had lost some 15.5 Lbs of weight. Nearly a pound
per day, for I am not sure which day of April I started to fast. Well
in any case it means, some 9.78 onces of weight per day.
The miracle is that after I started to fast for 24 hours... I discovered
I was ready to raise up my ass out of bed in the morning, and I was
able run up the three flats of stairs to the street, and go marching
at military pace up hill some distance, and then, on a level track,
and back uphill again, etc. I walked fast a modest distance like a mile
and went back home. I could not believe this was possible, for in the
past few years I almost was not doing any exercise. I called that a
miracle. I feel rather well, and I had been more prone to do some
physical tasks that were unthinkable some in the last ten or twelve months.
I was thinking my poor condition was due that I was getting rather old
and decrepit. My brain is also more clear, and more ready. Then, all
this obesity that to be causing problems also in my brain. The brain was
also getting full of fat, I suppose.

Then, I was looking for some videos and I had found this one and another
named "Sugar: The Bitter Truth",
https://www.youtube.com/watch?v=dBnniua6-oM

That last 1 hour 30 minutes. I watched from the start to the end.
I was really impressed. I was not eating much junk food, but it seems
that nowadays junk food is everywhere. They had added sugar even to
the bread; not only sugar, even some fat to make it tasty.

Anyone can be interested in this stuff.

Eri

[osugeography]

Hello, Eradinus, this is an interesting post, but I must question your calculation of the number of KiloCalories or KJoules in a Kilo of fat. First, the figures I see for the amount of water in fat are nowhere near the 80% you quote, and not relevant. Second, and this is much more important, I don't believe that you can say (very roughly paraphrased) "Here is a Kilo of fat. It is only 20% fat, and the rest water, so the energy content of one Kilo of fat is " 200 gr. of fat is some 1800 Kilocalories or 7524 KJoules". I believe the correct numbers are about 9000 KCAl or 37,000 KJoules. Anybody else? Marvin Sebourn osugeo...@aol.com

[eridanus]

El martes, 22 de abril de 2014 05:12:17 UTC+1, osugeography escribió:
> On Saturday, April 19, 2014 10:53:22 AM UTC-5, eridanus wrote:
>
> > The Secrets of Sugar - the fifth estate - CBC News
> > https://www.youtube.com/watch?v=xDaYa0AB8TQ

> > These comments have some relation to evolution even if it is not a

> > It last 1 hour 30 minutes. I watched from the start to the end.

> > I was really impressed. I was not eating much junk food, but it seems
> > that nowadays junk food is everywhere. They had added sugar even to
> > the bread; not only sugar, even some fat to make it tasty.
> > Anyone can be interested in this stuff.
> > Eri

try to expose and reason your argument.
Are you disputing that fat has more or less than 80% water?
Do you argue that the rest is mostly oil-fat? Except for some rests of
other material, the cells that that were forming the storage support?
I am using the common units of 9 kcalories per gram of fat-oil. It in a
kilo of fat, it can exist a little less than 200 grams of oil-fat. 190 or 185
grams perhaps.
From where do you take out the figure of 9,000 Kcal?
You had shown not the layout of your calculations.

Eri

[Richard Norman]

On Tue, 22 Apr 2014 01:54:55 -0700 (PDT), eridanus
<leopoldo...@gmail.com> wrote:

>El martes, 22 de abril de 2014 05:12:17 UTC+1, osugeography escribió:
>> On Saturday, April 19, 2014 10:53:22 AM UTC-5, eridanus wrote:

<snip leaving only the fat calculation>

>> >... I had calculated that 1 kilo of fat contains some

>> > 80% water and the rest is almost fat; then 200 gr. of fat is some 1800
>> > Kilocalories or 7524 KJoules.
>>
>> Hello, Eradinus, this is an interesting post, but I must question your calculation of the number of KiloCalories or KJoules in a Kilo of fat.
>>First, the figures I see for the amount of water in fat are nowhere near the 80% you quote, and not relevant.
>>Second, and this is much more important, I don't believe that you can say (very roughly paraphrased)
>> "Here is a Kilo of fat. It is only 20% fat, and the rest water, so the energy content of one Kilo of fat is " 200 gr.
>> of fat is some 1800 Kilocalories or 7524 KJoules". I believe the correct numbers are about 9000 KCAl or 37,000 KJoules.
>> Anybody else? Marvin Sebourn osugeo...@aol.com
>>
>

>try to expose and reason your argument.
>Are you disputing that fat has more or less than 80% water?
>Do you argue that the rest is mostly oil-fat? Except for some rests of
>other material, the cells that that were forming the storage support?
>I am using the common units of 9 kcalories per gram of fat-oil. It in a
>kilo of fat, it can exist a little less than 200 grams of oil-fat. 190 or 185
>grams perhaps.
>From where do you take out the figure of 9,000 Kcal?
>You had shown not the layout of your calculations.

The fact is that the human body is about 60% water although the number
varies over a wide range. Newborns can be up to 75% water and females
tend to have less water than males. That is because females tend to
have more adipose (fat) tissue than males and adipose tissue contains
significantly less water than other tissues. So if the whole body is
60% water, then adipose tissue would be far lower in water content.
The figure of 80% water is quite wrong. One study showed human
adipose tissue to be 10% to 20% water. The rest is almost entirely
lipid (what you call "fat-oil").
http://ep.physoc.org/content/47/2/179.full.pdf
So my guess is that you got the numbers confused: adipose tissue is
80% lipid ("fat-oil"), not 80% water.

One kilogram of pure lipid would have about 9000 kcal so one kilogram
of adipose tissue would have about 7000 to 8000 kcal in round numbers.

[Robert Carnegie]

On Tuesday, 22 April 2014 16:11:37 UTC+1, Richard Norman wrote:
> One kilogram of pure lipid would have about
> 9000 kcal so one kilogram of adipose tissue
> would have about 7000 to 8000 kcal in round
> numbers.

The figure that I heard somewhere is 1 lb = 3500 kcal.
1 lb is 454 grammes, I think. So that agrees with you?

It also means that increasing activity by 100 kcalories
expended per day, or reducing consumption - each being
a significant change of lifestyle - will have you
losing 1 lb in five weeks; 10 lb in a year. On the
other hand, a bearable and sustainable policy is
necessary for long-term wellbeing. Although I am not
a good example of that.

[Richard Norman]

The caloric content of fat is about 9 kcal/g so your number is
reasonable.

It is certainly true that, by the laws of thermodynamics, if you eat
more kcal (meaning actually digest and take into your body, what
passes through doesn't count!) than you expend with activity then
necessarily the excess must be stored somehow. For many organisms
that can go into growth and reproduction. For those non-pregnant,
non-lactating adults among us it pretty much means it goes into fat.

The real problem is that if you change your activity level you also
change your hunger and eating patterns and, conversely, if you change
your eating pattern your body can respond by changing your metabolic
rate. So 100 kcal per day spent or left uneaten need not convert into
10 lb/year. It can be more or less. Also many forms of exercise
result in increased muscle mass. It is all beneficial, of course, for
all sorts of health reasons but it may not show up in a quantitatively
"correct" weight change.

[eridanus]

> One kilogram of pure lipid would have about 9,000 kcal so one kilogram

> of adipose tissue would have about 7000 to 8000 kcal in round numbers.

ok, I accept the correction. But I do not invented those figures, I had
read them in some place. I had read as well that the human body is about 80%
water. And also that fat humans float easily than thin men, trying to
suggest that fat... well in this case, I committed a mistake for I also
remember that lipids or fat have less density than water. Then, a fat
man floats easier for it have more fat tissue, and then less density.

But somewhat I had fixed in my mind this number when I read
something about calories.
Then, if human fat contains less water, it contains more fat per weight.
So, I had read that a gram of lipids or oil, produces 9 kcal per gram.
While carbohydrates produced 4 kcal. per gram. I had fixed this in
my brain as some basic knowledge, for I was planning to do a solo
sailing around the world with a boat.

It took me a while to find this basic table, but here it is,
<http://dl.clackamas.cc.or.us/ch106-07/carbohyd1.htm>
I copy this text on the last two paragraph.

"The reason for this is the amount of oxidation that takes place as these
"compounds are converted to carbon dioxide and water. Carbon for carbon,
"fats require more oxidation to become CO2 and H2O than do carbohydrates.
"Roughly speaking, carbohydrates already have one oxygen for every carbon
"atom, thus, each carbon atom needs only one more oxygen and each pair of
"hydrogen atoms needs one more oxygen. However, almost every carbon atom
"in a fat molecule needs two oxygens instead of just one additional one, and
"each pair of hydrogen atoms still needs one more oxygen. So, just from
"counting the number of oxygens needed to be added, fats require about half
"again as much oxygen for the same number of carbon atoms. Because of this,
"the oxidation of fats takes longer, but it also gives off more energy.
"When comparing gram to gram, instead of carbon to carbon, the effect is
"exaggerated. When you weigh a carbohydrate, more oxygen is included in
"that weight. When you weigh a fat, you get more carbon atoms per gram
"and therefore, gram for gram, the fats will give even more energy (over
"twice as much) than will the carbohydrates. Generally, fats provide
"about 9 kilocalories per gram and carbohydrates provide about 4
"kilocalories per gram. (Using nutritional units, that is 9 Calories/gram
"for fats and 4 Calories/gram for carbohydrates.)

Then, if a kilo of fat contains about 80 to 90% lipids, then it has between
800 and 900 grams of fat, and that is 7,200 or 8,100 Kcal.
Well, fat tissue mut contain also some proteins, that formed the walls of
fat cells. How much is this? 5%? I do not know.

Then I was subestimating my calculations on calories lost by body
weight.
I was also doing some calculations about how much physical work was
needed to burn a kilo of weight.
Then I must revise the amount of work I was doing, and how much
efficiency my body has to produce some concrete "physical work", like
walking on a level ground or going up some hight.

Eri

[eridanus]

I had been accumulating fat in the last 12 months. The fatter
I got the more hungry I felt.

The surprising thing for me was that I felt like sick, loosing
all interest in moving, and feeling hungry all day, and eating
as well. I thought this was a sick condition, and it occurred
to me that to fast for 24 hours would change this condition.
I thought hunger would be tortured, but I felt less hunger than
in the previous normal days and months.
It did. The second day of fast I felt so strong and so well...
that I continued the fast. A while later I discovered that I was
able to walk some 30 feet of stairs running. I could not believe
it. It was more than 10 years I was not able to run upstairs.
Then, I took my wife to the work and went up for a long
walk for many streets, some were steep streets, other level
for I am living in a volcanic island that is rather mountainous.
Most of the cities are not build on level ground.
A few days later I was able to go higher and downward following
some streets to make more intense the walking. In all, it must be
some 750 feet of difference in hight that I walked, combining
with level tracks.
When i was eating again, I do not felt so well, but I felt not
hunger and was eating less.
Eri

[Richard Norman]

One problem is that you can't just think in terms of calories in and
energy expenditure. There are major hormonal shifts between feeding
and fasting, even the quite brief fasting between meals or overnight.
And with sustained fasting there are major changes in brain chemistry.
All these are associated with mood and emotional changes. Then there
are all sorts of psychological changes not clearly associated with
hormonal or chemical states just by learned associations or
expectations between mental state, activity, and eating.

For many people, perhaps even most people in developed countries, a
short period of fasting or restricted diet can be quite valuable. For
far more people in the world who constantly live in substandard
conditions on bare subsistence diets, it can be a disaster.

[Richard Norman]

On Tue, 22 Apr 2014 10:26:20 -0700 (PDT), eridanus

The technical difference between metabolizing carbohydrates and lipids
is the relative oxidation state of carbon. The web site you found is
from a community college where the students probably do not have the
backgound in general chemistry to understand at that level.

There are a large number of issues in calculating Calories per gram.
If you look at the nutrition label on food labels or in dietary
tables, one gram of fat means fat with no water and it provides 9
kcal. One gram of carbohydrate again means no water and provides 4
kcal. However "food" is very different. Fifteen grams of olive oil,
about 1 tablespoon, is fifteen grams of fat. Butter has some water
but is still generally 80% to 85% fat: fifteen grams would yield some
12 grams. So these would add 110 to 135 kcal to your diet. On the
other hand, fifteen grams of a grain like cooked rice is almost ten
grams of water and only some 5 to 6 grams of carbohydrate. So it adds
only 20 to 25 kcal. Even dry flour can be 10% to 15% water depending
on the relative humidity in your home. And some foods like lettuce
can be as much as 95% water. Meat can be 50% to 70% water.

There are also a large number of issues in calculating the energy cost
of exercising. You actually do zero physical work in running a 10k
race on level ground! (For nit-pickers, there is a very small and
completely negligible amount of work done against air resistance.)
Even when you do substantial amount of work in physics terms, the
efficiency at which you do it (the number of kcal of energy you burn)
can vary widely. So only 20% or so of you energy expenditure actually
goes into doing work.

[eridanus]

of course. I understand this perfectly. The problem I saw is that I was
a little fat, on the verge of obesity. Then, probably the excess of fat
was interfering with my metabolism and I was overeating because of lack
of enough physical exercise. It all started some ten of 15 years ago
when I began to write some novels.... and a while later when I was messed
with a group call humanities-literature that was a shock for me. It is
there that I met a frontal opposition of criticism on what I was writing.
I lost a lot of mental energy there trying to get some acceptance but
all was in vain.

Wall, I wasted a lot of energy in this writing, and a lot of heated
arguments about literature values... and... at the end I had to surrender
and go out of the place. The place become so poisoned with bad tempers
that most people fled the place. The main reason were two Marxists
warriors that wonted to focus the interest of the group on Marxism and
let out all this nonsense of literature criticism.

Well, after all this time on the computer writer I was abandoning the
minimal needed physical exercises and this made me almost obese.
Then, in the later years I was feeling worse. I understood this as
I was getting older and accepted. But the recent experience, of eating
so often made me even fatter, and in constant hunger. I understood that
this was a metabolic disorder, for it made not any sense that I was so
fat and feeling hunger so often. Then, I concluded that I was ill of
being so fat, and this fat somewhat caused some disorder in the
metabolism of hunger. I should not feel any hunger for I was rather
fat. Then, as I decided to fast seriously. This is the best idea I had
in years. If my doc would had advised me to do it, I would probably
would not believe him. I am a little rebel to the figures with authority.

I had read many times about the virtues of frugality in eating. But as
I passed so much hunger during my childhood, mostly a the time of
lunch, and I was so thin... that I could not believe any word about the
virtues of frugality. I had ingrained in my brain the to suffer hunger
was a bad thing. I am believing now, that to pass a time fasting or
feeling a little hunger was something good for the stability of metabolism.

On the other hand, I had read that exercise rises the levels of adrenaline
and that ask for the organism to produce glucose out of any storage in
the liver or the muscles. As the stored glucose is being consumed, other
mechanisms began to act to metabolize some fat to make glucose to replace
the one was consumed. Then, I had the idea that to be so long time at
the computer was a sort of abnormality. That the body needed some minimum
of exercise; but this idea was rather theoretical, for I never was fan
sports or physical exercises. Only when younger I did enough exercise.
But in general, my passion was thinking, read, and write. Not doing any
exercise. I do not think I had insulin resistance, but rather an over
action of insulin that lowered the levels of glucose in the blood in
excess; and this caused the feeling of hunger after a light meal.
I needed then to active the levels of insulin to maintain a proper balance
of glucose in the blood. The only way to do that was to do physical
exercises. Then, by starting the fast, the body was force to call some
hormone, probably adrenaline, to force the liver to release glucose.
This way, I discovered as I said, that after feeling a little hunger
for ten or twenty minutes it soon disappeared like a miracle. Then it was
much easier not to feel hunger when I ate not anything. In subsequent days
I was like half fasting; that is eating nothing till past noon. But then
eating about half the ordinary amount of food I used to.
In general, it is easier to maintain a fast when not eating anything.

I do not enter into this for having expectations, but because I was alarmed
of my pitiful state. I could not believe I was passing for this shit,
of being constantly eating because I felt hungry. It was absurd.
I hypothesized that the primitive man had to feel hunger quite often,
outside the short period of abundance. Then, I reasoned that the
our metabolism was conformed to suffer some frequent periods of forced
fast, for lack of food. In those periods, the body was feeding itself
from the reserves of fat. Then, to be hungry in the normal stages,
was something normal. What was not normal is the present state we had
in which we have never a scarcity of food, and eat daily a little more
than we need to maintain our normal levels of physical activity. There
is something in our diet that is missing, some real physical hunger,
cause by having nothing to eat.
It is a theory I made. I suppose is has sense. I look a rational
argument.
Eri

[eridanus]

in general I am well informed about this. But for theoretical reasons
I wanted to focus on the problem of loosing weight.
In Europe the lobbies of the food industry had achieved that most
information is rather confused, and do not tell the details of the content.
Only the overall calories, from fats, or hydrocarbons. Some foods like
modern bread, and other bags of junk food do not enter in details: only
tell the amount of calories from fat and carbohydrates. But do not tell
how many grams of sugar or fructose it has a product. The problem with
sugars and fructose is that it is contained in many products you do not
expected that would contain any. And this sweet stuff do not make feel
satiated. Then, you tend to eat more than you need.
The case is that sugar and fructose is rare in Nature. And as primitive
humans we never had sugar or fructose in our daily diet but in minimal
amounts. Then, we had not any mechanism of alarm for this problem that
is mostly related to modern industrialized foodstuffs. Two hundred years
ago, the sugar was very expensive and a source of taxes for the state.
I had read that in France in the early 19 century a third of the taxes
collected came from sugar. When Haiti rebelled and become independent
Napoleon was deprived of this source of income, and offered a prize
for anyone who would invent a substitute for the production of sugar.
Someone, I do not recalled the name, invented sugar from beets. The
empire was saved for a few years to succumb later to the megalomania
of Napoleon and its wars.

Eri

[Roger Shrubber]

Richard Norman wrote:

> There are also a large number of issues in calculating the energy cost
> of exercising. You actually do zero physical work in running a 10k
> race on level ground! (For nit-pickers, there is a very small and
> completely negligible amount of work done against air resistance.)

As a lad working for an electrical engineer, I was doing some
routine motor assembly work. One day it came to pass that his
son tried to explain to me that walking 3 miles, or running
3 miles or doing 3 miles as a bunch of sprints burned
exactly the same number of calories because it was exactly
the same amount of work. I somewhat bruskly told him he
was wrong and it turned out his father came to defend him.
He of course invoked that work = force x distance, QED.
I tried to point out that the simple formula has force
as a vector in the direction of the distance, and anyway
it was a question of efficiency. The better model would
be to look at jumping 3 miles, working against gravity
with a horizontal offset, then refine. No go. Work equals
force x distance. An EE remembered that much physics,
and that much physics was gold. So I asked if he thought
it took the same amount of work to cover the 3 miles on
a bicycle. No he said, because you are using a machine.
So machines violate the laws of physics I asked? Then
I was told not to be a snotty ahole and get back to work.
I think I got laid off the next week but hired back
the following week when a big order came in. It was a
pretty decent job as I recall, at least as far as _The
Summertime Blues_ goes.

[eridanus]

El martes, 22 de abril de 2014 23:01:17 UTC+1, eridanus escribió:
> El martes, 22 de abril de 2014 20:38:02 UTC+1, Richard Norman escribió:
>
> > One problem is that you can't just think in terms of calories in and
> > energy expenditure. There are major hormonal shifts between feeding
> > and fasting, even the quite brief fasting between meals or overnight.
> > And with sustained fasting there are major changes in brain chemistry.
> > All these are associated with mood and emotional changes. Then there
> > are all sorts of psychological changes not clearly associated with
> > hormonal or chemical states just by learned associations or
> > expectations between mental state, activity, and eating.
>
> > For many people, perhaps even most people in developed countries, a
> > short period of fasting or restricted diet can be quite valuable. For
> > far more people in the world who constantly live in substandard
> > conditions on bare subsistence diets, it can be a disaster.

> Of course. I understand this perfectly. The problem I saw is that I was

> a little fat, on the verge of obesity. Then, probably the excess of fat
> was interfering with my metabolism and I was overeating because of lack
> of enough physical exercise. It all started some ten of 15 years ago
> when I began to write some novels.... and a while later when I was messed
> with a group call humanities-literature that was a shock for me. It is
> there that I met a frontal opposition of criticism on what I was writing.
> I lost a lot of mental energy there trying to get some acceptance but
> all was in vain.
>

> Well, I wasted a lot of energy in this writing, and a lot of heated

This line contains an error. I meant adrenaline, not insuline. It should
be read...
> I needed then to active the levels of adrenaline to maintain a proper balance

> of glucose in the blood. The only way to do that was to do physical
> exercises. Then, by starting the fast, the body was force to call some
> hormone, probably adrenaline, to force the liver to release glucose.
> This way, I discovered as I said, that after feeling a little hunger
> for ten or twenty minutes it soon disappeared like a miracle. Then it was
> much easier not to feel hunger when I ate not anything. In subsequent days
> I was like half fasting; that is eating nothing till past noon. But then
> eating about half the ordinary amount of food I used to.
>
> In general, it is easier to maintain a fast when not eating anything.
>
> I do not enter into this for having expectations, but because I was alarmed
> of my pitiful state. I could not believe I was passing for this shit,
> of being constantly eating because I felt hungry. It was absurd.
> I hypothesized that the primitive man had to feel hunger quite often,
> outside the short period of abundance. Then, I reasoned that the

our metabolism "has evolved" to suffer some frequent periods of forced

> fast, for lack of food. In those periods, the body was feeding itself

> from the reserves of fat. Then, to be hungry in the normal times,

[Richard Norman]

One problem with your story is that you really do pretty much burn the
same number of calories if you walk, run, or do sprints for three
miles. It is very true that the faster you go, the higher your
metabolic rate. But you also get there quicker. If metabolic rate is
directly proportional to speed, then the energetic cost of traveling a
given distance is independent of speed. In fact, to a pretty good
approximation, metabolic rate is a constant plus a factor that is
directly proportional to speed. That constant is the cost of keeping
you alive; when you stand still your metabolic rate is not zero.

Your jumping analogy is very wrong as is the bicycle comparison. The
cost of locomotion has to do with the way that energy is spent making
the appendages move and then stopping them from moving and making them
move backwards to complete the stepping or running cycle. If we had
elastic systems to recapture the energy we would be far more
efficient. We do to a very small extent and other animals have much
greater elastic energy recycling and are more efficient. Flying and
swimming have their own peculiarities and the energetic cost of
locomotion per unit of distance travelled does tend to be more
dependent on speed.

An awful lot about the naive application of physics to human systems
is simply wrong. Physics certainly does apply but only when you take
into account the biological details.

[jillery]

On Tue, 22 Apr 2014 18:23:42 -0400, Roger Shrubber
<rog.sh...@gmail.com> wrote:

The difference between running three miles and walking three miles is
that in the former, the rate of work, or power, is greater, not the
work itself. Running three miles is faster, which gives one more time
to do even more work.

And even a crabby old EE should remember the difference between joules
and watts.

Of course, the laws of physics are often trumped by the laws of the
workplace.

[eridanus]

of course, the body as a working machine is not very efficient.
The efficiency varies as a function of the power used. Being
power the energy consumed per second. If you walk on a steep
street very slowly, like in half an hour or more, you would not
breath heavily or sweat or accumulate any heat. But if you
pretend to do it as fast as you can you will puff and blow and
sweat a lot to refrigerate the body. Then, the heart has to
pump a lot more blood per second, and your lugs hat to take
a lot more air to oxidate that much glucose that is needed
per second.
Then, the efficiency of the machine working very slowly can
be close to 20 or 30% But when working rather fast can
be lower than 5% The faster the heart has to pump blood
on the system, the more resistance due to viscosity has
to overcome the system.
Even walking on a level ground a distance does not consume
the same amount if you go rather slow, or rather fast.
For when we walk, on each step we have to raise a leg some
hight. The faster you walk the higher is raised the leg.
But not only the leg. I watched that the body goes up and
down an inch or two depending on the speed of the walk.
Then the center of mass of the body is going up and down
constantly as it walks. The center of mass of the body is
doing some wavelike function as he walks, and this makes
some difference as a work.
I had observed this as I was walking several times. the body is going
up and down as one walks. This is specially noticeable if we are walking
beside some metallic barrier between the road and the sidewalk. You look
at the lines painted on the road, and you can see they go up and down
over the upper rail of the metallic fence. That's the way I realized
the body goes up and down as it walks.
Then, if we have our arteries full of cholesterol this increases
the friction and natural viscosity of the blood increases the
work of the heart for the arteries had shrunk the inner diameter
with some plaques of fat.
Then, if you walk faster it is involved more power or energy
per second. This lowers the efficiency of the body as a
machine that works.

Eri

[eridanus]

I disagree with this statement. One question is the amount
of physical work, in the physical sense. Like to raise your body
weight of 165 lb to 1,000 feet of hight. This is in the physical
terms of a dead body that is raised up some hight, or the is dragged
some distance against some friction on the floor.

Another question is the work done by the body as a biological
machine. Even cars have an efficiency between 25 and 30%
It means 70 or 75 % of the energy is transformed in heat.
then we must detract from this some frictions on the wheels
and the other rotating mechanism. I had read somewhere
that the efficience of cars was around 20% or less. But I am
not sure of these data.
The human machine is also a case. Most of the energy
involved in doing a physical work is consumed to make the
body work. The blood has to irrigate faster all parts of the
body, specially the muscles. The lungs have to take in more
liters of air per minute, etc. And you must consume glucose
to make the muscles and the brain work.
What is the efficiency of the body as a working machine,
I remember I had read something like 20 to 5%. I have some
files with the data in some part of the computer. It depends
on how fast is being done the physical work.
Then, the burning of calories depend mostly on the potency
involved in the work, more than in the external physical
work.
So, we must discern two parts. How much is the the external
physical work to be done, and how much expends the body
as mechanic machine to do a work. Think that the body is
consuming energy even when doing nothing. For it is breathing
constantly, has a heart pumping continuously, and has to
maintain the temperature. The brain is mostly working
continuously and consumes about 20% of the energy of the
body on average.

> Your jumping analogy is very wrong as is the bicycle comparison. The
> cost of locomotion has to do with the way that energy is spent making
> the appendages move and then stopping them from moving and making them
> move backwards to complete the stepping or running cycle. If we had
> elastic systems to recapture the energy we would be far more
> efficient. We do to a very small extent and other animals have much
> greater elastic energy recycling and are more efficient. Flying and
> swimming have their own peculiarities and the energetic cost of
> locomotion per unit of distance travelled does tend to be more
> dependent on speed.
>
> An awful lot about the naive application of physics to human systems
> is simply wrong. Physics certainly does apply but only when you take
> into account the biological details.

The case of the bicycle is different to walking. I had not made the
analysis of the difference, for it is rather a novelty to me, and I had
never considered this problem. Of course, there is some work involved
also in a bicycle. But I am not sure how to analyze it.

Eri

[Roger Shrubber]

I think the jumping analogy sets the maximum expenditure of energy,
to be corrected by muscular efficiency and discounting the sort of
rebounding effects seen in kangaroos. Running versus walking versus
sprinting sets up a biophysical question of conservation of
momentum and efficiencies due to elasticity in tendons. But it is
far more complicated, and very different than W = F x D.

> We do to a very(vary) small extent and other animals have much

> greater elastic energy recycling and are more efficient. Flying and
> swimming have their own peculiarities and the energetic cost of
> locomotion per unit of distance travelled does tend to be more
> dependent on speed.
>
> An awful lot about the naive application of physics to human systems
> is simply wrong. Physics certainly does apply but only when you take
> into account the biological details.

Well I do beg to differ, beging a beggarly sort of person.
Not with respect to your final statement. There I agree
about taking into account biophysical details.

Let's consider the case of a identical twins, one walking 3
miles at an economical pace versus their twin running 3 miles
at a world record pace and then doing as little as possible
until their twin finishes their stroll. Or perhaps there are
triplets and we have another running 100 meter sprints, briefly
resting, and running another sprint 25 seconds later, walking
leisurely between sprints, subsequently 'chilling' like their
sibling who ran 3 miles straight.

Between the simultaneous start time and the ending time, the
sprinter will have burned more calories, the runner next, and
the walker last.

I admit this shifts the question some but in the direction
of reality as there is a basal metabolism that exists regardless
and is in fact enhanced after vigorous exercise.

But if we are comparing walking, running, sprinting or even
cycling 3 miles, we it's really an incremental increase in
the daily burn. If the fastest method is filled in by
doing deep knee bends that the others don't do it's a
bizarre scenario. The best time fill in is minimal
activity (he says, recliner extended, glass in hand,
reruns on the tube, back throbbing from digging out
stumps earlier in the day)

[Richard Norman]

On Tue, 22 Apr 2014 20:16:01 -0400, Roger Shrubber

The problem with your story is that people have actually done the
studies and measured the metabolic rates. Consider triplets over a
time period of one hour. One spends the hour walking at the most
natural and comfortable pace. A second, trained in distance running,
runs for perhaps fifteen minutes and then rests for 45. A third just
trots or jogs for about a half hour and rests the other half hour. I
say that the three will burn about the same number of calories during
that hour.

Extreme paces work a bit differently as in walking or sprinting at the
absolute fastest you can. But under normal and comfortable
conditions, walking, jogging, and running all use pretty much the same
amount of energy per distance travelled.

Forget the bicycle -- it is very different. You might also want to
forget ice skates and the like.

[Richard Norman]

The question here is the amount of external physical work to be done.
I say that to move at constant velocity for a distance on a level
surface that work is zero because frictional resistance is quite
minimal. Yes you do internal work. However I said that the total
energy you spend to move, say, one mile does not depend on how fast
you travel that mile within reason. That is, walking, jogging or
running are all quite similar.

[Roger Shrubber]

Basic math. It is suggested that running or walking the same distance
consumes similar calories. But running the same distance consumes those
calories more quickly, so as the runner waits (and continues to consume
calories) for the walker to catch up, the runner extends the calories
burned.

You have asserted both that the same amount of energy is consumed
by running or walking 3 miles as is consumed in 1 hour by one who
walks 3 miles and one who runs 3 miles and then rests until the
hour is over. Pick one. Both cannot be true unless resting burns
no calories, and this is not true.

> Extreme paces work a bit differently as in walking or sprinting at the
> absolute fastest you can. But under normal and comfortable
> conditions, walking, jogging, and running all use pretty much the same
> amount of energy per distance travelled.
>
> Forget the bicycle -- it is very different. You might also want to
> forget ice skates and the like.

Yes, differences in efficiency are much greater for bicycling or
skating and walking than between running and walking. The magnitude
of difference between running and walking is a separate question.

[William Morse]

It has been noted that rich people in rich countries and poor people in
poor countries are thin, while rich people in poor countries and poor
people in rich countries are fat (this is obviously an
oversimplification, but I think it has an element of truth.) The
explanation is that rich people in rich countries can enjoy the benefits
of a restricted diet without fear of the consequences of a short period
of famine - they won't experience a short period of famine. Poor people
in poor countries simply do not have access to enough calories to become
fat. Poor people in rich countries and rich people in poor countries
have access to enough calories to become fat, but still can experience
short periods of famine. So there may be social pressures in addition
to all the other varied influences of diet and exercise.

[eridanus]

I was not disputing the case external work done. if your raises some
hight, you had move a mass so hight against gravity. This does not
change if you go fast or slow. But the the body machine is subject to
thermodynamic laws. There is a work to be done inside the body, like
pumping blood, by example and breathing. Then, the resistance of the blood
to run within the vein system increases a lot with velocity. The system
has to evacuate a lot of heat much faster, and this can explain the
difference of thermodynamic performance.
A similar case can be considered in a car. If a car runs slowly, a degree
of energy is lost for a machine of some power in friction and heat. If
the car goes faster, an optimal faster, the productivity of the machine
increases, but if it goes very fast, over some 45 miles/h, the friction
of the air start to be important, as the square of velocity. At 75 miles/h
the friction of the air began to be important in the consumption of energy
per distance. Not only is important the external friction of the air over
the car, but the friction of air entering the admission tubes, and on the
exhaust tubes. To minimize these constrictions the racing cars are done
with a much lower profile and some form of wings to push the car against
the road. For at high speeds at 190 miles/h could easily lift off the
floor and start to fly a little, loosing the grip of the tyres and speed.

Then, one thing is the work done, per se, on a external mechanical work,
another question is the work involved inside the body. The body machine
is already consuming energy by standing quite. Then, when it starts to
do some minor work, like walking slowly, the effort done is negligible
in regard to the body consumption of energy.
As the walk becomes faster, the the curb simply goes up a little up
as energy consumed per second. Then, there is a moment, in which the
external mechanical effort is optimal for a body, depending on the age and
its optimal training and capacity. Passing from this point, I can figure
that the energy consumption per second, is a little more than the energy
the done to perform some external work. Then, if the external work increases
per second, the internal work of the body increases as well; then the ratio
changes. For very high speeds, like running, the body is consuming more
energy internally than the work done on the outside. Then, it begins
to heat, and this is also a limitation. When the internal heat of the body
approaches the 40 C degrees (104F) it is on the brink of a collapse and the
runner has to stop. He is loosing sodium in the perspiration very fast, and
also loosing water and some electrolytes. As the body looses water by
sweating, the viscosity of the blood increases as well, the it cost a lot
more to pump blood. In this moment, the body is on the brink of collapse.
I watched a video in which it was explained the case of a walker that
pretended to cross the Dead Valley on a heat of great heat. He let on a
side of the valley his SUV car awaiting for him, and the sheriff brought
him to the other side of the valley, advising him that this was a bad
weather to cross the valley on foot. He nevertheless was determined to
do it.
He was found dead at some twenty or thirty yards from his car. He could
not reach his car and collapsed at a sort distance. The narrator was
explaining the process, as how the walker was loosing water, and he
was only carrying a bottle of water. As the water of the bottle was
consumed, his blood began to loose water as well and it soon collapse.
probably more for lack of water than from the heat. Also I read in some
part the in cases of extreme heat, our brain does not work properly
and start to fail. When the temperature of the brain is approaching
some threshold near 100 F it begins to show some problem. It tends to
collapse. This man of the story collapsed before making some tens of
yards towards his car, where surely it was some more bottles of water.

Then, the simple act of pumping blood generates friction within the blood
vessels, the faster the heart is pumping the greater the resistance of
the blood to move because of viscosity. Other works like burning fat
requires a complex process, and there is a moment in which the body is
burning fat, to let in store some glucose in reserve. This is when the
body begins to accumulate lactic acid as a residue.

You must consider the human body, or any animal body, as a thermodynamic
machine that is perfect for some amount of work during limited intervals
of time. Below or above some values of work, the machine is loosing
efficiency. On both extremes of work lasting large periods, the biological
machine tend to deteriorate.

If one passes too long a time doing a zero work, the machines began to
loose power and capacity, and the endocrine and metabolic system is deteriorating. That is why the political systems used to put their
enemies in dungeons or prisons, to break down the most dangerous machines.
In the other extreme, like in labor camps, the prisoners are forced to
deliver some amount of work for a minimal ration of food. The animal
machines were loosing reserves and got soon on the brink of starvation.
Then, they cannot challenge the penal system and reject to do the demanded
work for they are on the brink of starving. They can afford to pass a day
without eating, they had had not any reserves of fat. These machines are
inefficient and probably are going very fast to their death; but this is
not a question that would worry the leaders of this society that sent them
there.

Eri

[Walter Bushell]

In article <b8db512d-8c15-4b62...@googlegroups.com>,

eridanus <leopoldo...@gmail.com> wrote:

> In Europe the lobbies of the food industry had achieved that most
> information is rather confused, and do not tell the details of the content.
> Only the overall calories, from fats, or hydrocarbons.

s/hydrocarbons/carbohydrates/

The words shape to mean the same thing, but they don't actually mean
the same thing. Anguish idioms can be very difficult even coming from
another IndoEuopean language.

--
Never attribute to stupidity that which can be explained by greed. Me.

[Walter Bushell]

In article <xIKdnRUl-sKpm8rO...@giganews.com>,

Roger Shrubber <rog.sh...@gmail.com> wrote:

>
> I admit this shifts the question some but in the direction
> of reality as there is a basal metabolism that exists regardless
> and is in fact enhanced after vigorous exercise.

And the human brain takes up an enormous proportion of human metabolic
energy and does no external work at all. I remember reading that chess
masters in significant clashes can consume energy as much as athletes
in competition and Bobby Fisher was famous for his swimming which he
said gave him staying power.

[Richard Norman]

This confuses several rather different notions of explanation. It is
no doubt true (though finding definition evidence to prove it is
difficult) that there is an evolutionary tendency to stuff yourself
whenever rich sources of food are available. That is because such
rich sources are rare and much of the time you depend on living off
internal stores of energy. You use that to explain obesity in two
circumstances. It is the old story of Joseph in Egypt (Genesis 41)
with the seven fat years and the seven lean years.

On the other hand, it is extremely unlikely that any rich person
living in a rich country ever sat down and figured out "I don't have
to be fat because I have no fear of facing a famine. Therefore I will
keep myself thin." Similarly a poor person in a rich country does not
sit down and fiture out "I better stuff myself and become morbidly
obese because if I lose my job at least I will be able to live off all
that fat."

So the tendency to become overweight in the midst of plenty might have
originally had an evolutionary basis, the personal choices of
individuals to remain slender really must be explained on social
factors or other reasons. Even the notion that "plump children are
healthy children" so common in so many societies is largely a cultural
issue that may have had evolutionary roots but the cultural issues far
outweigh the genetic.

[Richard Norman]

On Tue, 22 Apr 2014 21:39:57 -0400, Roger Shrubber

If you simply plot energy/distance (the cost of locomotion per mile)
vs. speed you get a sort of U-shaped curve with a very broad and
pretty flat bottom. For very slow speeds you get very high cost
because the general cost of living (basal metabolism) predominates and
doesn't contribute at all to locomotion. At speed zero, you spend
infinite calories per mile! Also at the extreme fastest end, your
gait is severely compromised and the energy cost increases. However I
am really talking about that very broad flat area where the cost per
mile is relatively constant.

Another way to view it is to see that, to a really good approximation,
the metabolic rate (which is energy/time or power) vs speed is a
straight line but displaced from zero by the basal metabolism. In
that case, metabolic rate (power = energy/time) divided by speed
(distance/time) does not give a constant value for energy/distance.
However the "excess energy of locomotion beyond basal metabolism" does
produce a constant value for energy/distance.

Walking is rather different and the energy does very with speed but it
turns out that at the normal and most comfortable pace the energy cost
of walking is essentially the same as running at that speed.

[Richard Norman]

On Wed, 23 Apr 2014 07:31:51 -0400, Walter Bushell <pr...@panix.com>
wrote:

>In article <xIKdnRUl-sKpm8rO...@giganews.com>,
> Roger Shrubber <rog.sh...@gmail.com> wrote:
>
>>
>> I admit this shifts the question some but in the direction
>> of reality as there is a basal metabolism that exists regardless
>> and is in fact enhanced after vigorous exercise.
>
>And the human brain takes up an enormous proportion of human metabolic
>energy and does no external work at all. I remember reading that chess
>masters in significant clashes can consume energy as much as athletes
>in competition and Bobby Fisher was famous for his swimming which he
>said gave him staying power.

It is true that the brain uses a disproportional (to its mass) amount
of metabolic energy, about 20% of resting metabolism or some 300
kcal/day. However thinking hard does not increase that by any
significant amount. Thinking really hard during a chess match might
have cost Bobby Fisher (or anyone else) perhaps an extra 10 kcal
total. One piece of candy or one teaspoon of sugar in a cup of tea
would more than remedy that. However the incredible stress of a chess
match produces far greater changes and has far more significant
physiological implications so being in good physical shape can be very
important. I heard that perhaps a main reason why Garry Kasparov lost
to the computer Big Blue had to do with the cumulative stress and
fatigue exacerbated by other factors surrounding how the match was
conducted rather than pure chess knowledge and strategy. The computer
never got tired or irritable or annoyed or angry. The energy demands
on Kasparov's brain had nothing to do with it.

Incidentally, the kidneys and the brain, the two largest energy hogs
in the body, do no mechanical work at all. Instead they do chemical
work in terms of moving ions across a membrane against an
electrochemical gradient. For the most part, that means moving sodium
ions from a region of low concentration and at a relatively negative
electrical potential into a region of high concentration and a
relative positive electrical potential. That means doing chemical and
electrical work.

[William Morse]

The original observation about rich vs. poor people in rich vs. poor
countries comes from Melvin Konner's "The Tangled Wing", and I do not
think it confuses different notions of explanation. As I understand
Konner, it is about the interaction between culture and genetics, and
how that affects individual behavior. It is not just about the
evolutionary tendency to take advantage of "high quality" food sources,
which has been exploited by current corporations to sell products which
are high in sugar, salt, and/or fat.

The rich person in a rich country may not perform the calculation you
refer to, yet there is the phrase "you can't be too rich or too thin".
Similarly, Konner is not talking about the poor consumer in the US who
is led to become morbidly obese from a number of factors having to do
with US trends in marketing and government subsidies for certain crops,
he is talking about social influences in societies that generally have
enough to eat but in which the poor may experience occasional periods of
starvation. IIRC, he presents evidence about how other historical
societies experienced periods of starvation.

The point I was trying to make is that there are social mores regarding
weight that also affect an individual's actions regarding diet and
weight, and that some of these have roots in evolutionary explanations.

[eridanus]

El mi�rcoles, 23 de abril de 2014 01:54:01 UTC+1, Richard Norman escribi�:

> On Tue, 22 Apr 2014 16:46:27 -0700 (PDT), eridanus
>
> <leopoldo...@gmail.com> wrote:
>
>
>

> >El martes, 22 de abril de 2014 23:52:56 UTC+1, Richard Norman escribi�:

I thought this was not the question, but the energy consumption of the
living being doing the work.
I am not an expert in the physiology of the work, or ergometry I suppose
it is called; but I do not believe you are either.
So, I postulated from my ignorance, that it exist a barrier of efficiency
of biological machines determined by several constrains; one of these
constraints must be the friction of the blood in the circulatory system.
Then, it exist a moment of maximum efficiency, not related to the maximum
capacity to deliver some amount of work by a muscular system. For sort
surges of great work the system have natural limitations. A predator
or a pray rarely can surpass some threshold of energy consumption per
second, and even near this threshold has a limited amount of time.
This is obvious from our experience watching those that run for a purpose,
like Olympic runners, predators or preys. There are small differences
among the different athletes and in general animals that run; but this
inspires to me the idea that exist a growing resistance of the blood to
pass those the vascular system, as a function of the square of velocity.
That would explain the limit, but there must exist other limitations
as well, like how fast the body can transform fat to deliver glucose
to the muscles and in general to the blood.
Thus is my idea that even if the mechanical external work done, to move
a mass to some distance, the inner work of the body is not lineal with
the external work done. There is an optimal pace of work for the
machine, but it cannot be constantly doing this optimal work without
a profitable purpose, for the body is consuming energy, and should take
into account and conserve the reserves. The optimal pace can be used
by a body when it is exploring in search for an opportunity to find some
food, or some prey or other reason. In absence of hunger, most predators
are simply resting. This function is also needed to repair some wearing
or small breaks here or there, in the body.

Eri

[eridanus]

El mi�rcoles, 23 de abril de 2014 02:39:57 UTC+1, Roger Shrubber escribi�:

> Richard Norman wrote:
>
> > On Tue, 22 Apr 2014 20:16:01 -0400, Roger Shrubber
>
> > <rog.sh...@gmail.com> wrote:
> > The problem with your story is that people have actually done the
> > studies and measured the metabolic rates. Consider triplets over a
> > time period of one hour. One spends the hour walking at the most
> > natural and comfortable pace. A second, trained in distance running,
> > runs for perhaps fifteen minutes and then rests for 45. A third just
> > trots or jogs for about a half hour and rests the other half hour. I
> > say that the three will burn about the same number of calories during
> > that hour.
>
> Basic math. It is suggested that running or walking the same distance
> consumes similar calories. But running the same distance consumes those
> calories more quickly, so as the runner waits (and continues to consume
> calories) for the walker to catch up, the runner extends the calories
> burned.

OK. Explains us what are those basic maths. It refers to the maths
of the working body? What are the reasons for the limits of physical
work delivered by a muscular system?
I do not think there is any basic maths to understand how the body
works at different speeds. Even if moving slowly is not particularly
productive in caloric terms, it permit the walker to watch the environment
in search of opportunities to hunt, or simply to avoid some dangerous
predator. Then, it make sense to go somewhat slow, for the organism
is in a exploring mode. Most of the work is being done by the brain
that is analyzing the environment.

Then, I think that some works of high intensity consumed a lot more
energy than the mechanical work done. I mentioned in another post
that the blood has some viscosity and the resistance of the veins to
this circulation must be some square function, not lineal.
While the less friction for the blood circulation is when is slower,
but as someone said the body is not doing any external physical work.
Of course, I can consult some tables of ergonomy and muscular
efficiency. I remember I had copied some notes about this matter
but I feel lazy to look for these notes among the thousands of
files stored in my computer. The efficiency of the body is maximum
for small amounts of work, but is bellow around some 5% for extreme
spurs of energy expenditure. This is the reason why animals do it
mostly in some special moments and for short periods of time.

A way of primitive hunters in hot environments is to go for a
prey, the prey watching the man flee, but the man continues at
a medium velocity to go after the prey that has to stop to cool,
but the man has most resistance to heat because it can sweat;
then as the animal stops the man come near him, and the animal
continues is fleeing. After a couple of hours, the animal is
exhausted mostly by the heat, and he cannot move. It is
refreshing his blood by breathing heavily. The man then
arrives and spears the animal and kill it. The peak of
running of the animal is greater than that of the man. But
the man wins after a time, for it does not overheat that easily.
But even, the man has to have some spare water with him
to achieve this persecution, for as it looses some water by
sweating, he would be unable to run anymore, if he does not
drink. Sweating is good to refrigerate but if you do not
replace the water lost, the blood becomes thicker and its
viscosity increases. Deliver blood to all parts of the body
becomes very difficult, and this is specially serious for
the brain that is the master director of any physical strenuous
work.

Eri

[Walter Bushell]

In article <ljce5...@news4.newsguy.com>,

William Morse <wdNOSP...@verizon.net> wrote:

> The rich person in a rich country may not perform the calculation you
> refer to, yet there is the phrase "you can't be too rich or too thin".

A friend of a friend of mine died of anorexia and a rich guy I knew
could have anything he wanted and he wanted cocaine. He would keep a
sugar jar on his living room table and any visitor could help him or
her self. Is possible for either to be a negative.

And then there are the cases of affluenza, which allowed at least one
teen to literally get away with murder.

[Richard Norman]

On Fri, 25 Apr 2014 01:38:47 -0700 (PDT), eridanus
<leopoldo...@gmail.com> wrote:

>El miércoles, 23 de abril de 2014 01:54:01 UTC+1, Richard Norman escribió:

<snip>

>> The question here is the amount of external physical work to be done.
>> I say that to move at constant velocity for a distance on a level
>> surface that work is zero because frictional resistance is quite
>> minimal. Yes you do internal work. However I said that the total
>> energy you spend to move, say, one mile does not depend on how fast
>> you travel that mile within reason. That is, walking, jogging or
>> running are all quite similar.
>
>I thought this was not the question, but the energy consumption of the
>living being doing the work.
>I am not an expert in the physiology of the work, or ergometry I suppose
>it is called; but I do not believe you are either.

>So, I postulated from my ignorance, that... <snip>

That the amount of physical work done is zero shows that the actual
energy consumption of the living being has no connection with physical
work.

I am not expert in the physiology of the work but happen to be
extremely knowledgeable in it and have taught this stuff for several
decades. I am not postulating from ignorance but rather citing the
results from people who are expert and who have studied this
extensively. Before writing my posts I consulted a variety of texts
and verified that the graphs showing actual experimental data on
metabolic rate of humans at various speds and gaits demonstated what I
was saying.

I know you dislike mere "authority" and say that science has been
wrong about some things before and therefore can be wrong about
anything else at any time. However the measurements of energy
consumption have actually been done and I do know what they show.

[eridanus]

I could easily look for papers also in the net that would confirm my
"imaginative speculations". I was saying something reasonable, but
you had only pointed to other sources "you say to know" but do not
make them explicit. What sources are those, but just that you knew
them. You were presenting some indirect authority. It was not just
you, but some in authority the permitted you to challenge my argument.

So, far in a mere couple of minutes, I had found two papers in pdf
that favor my thesis, that exist a differential of muscular efficiency
for different outputs of work. I could easily found a dozen more
if I keep looking for them.


<http://www.google.es/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CDYQFjAA&url=http%3A%2F%2Fbiolsport.com%2Ffulltxt.php%3FICID%3D891552&ei=7SdaU9ucF8TE0QWg7IHYBg&usg=AFQjCNF7c3AuvIbZyRoXq7l59MC_jgU5Yg&sig2=dI-FMb2k1RBzMi2bgsBmVQ&bvm=bv.65397613,d.Yms>

This can be found with the Google under the name "Power Output and
Mechanical Efficiency at Pedaling".

Other article, called "The reliability of cycling efficiency".

In both articles from different sources, can be found about these facts,
that there is an optimum efficiency for a physical effort. To me,
the question was so trivial I did not not take the work of looking for documented confirmation when I was alleging my point of view. Then I was
rather surprised at your repeated assertions that it was indifferent
the rate of work from the point of view of the efficiency, what simply
implies we are consuming a lot more energy for some rates of power
delivered. There is not a lineal correlation for some critical outputs,
for the resistances inside the body grow exponentially for as the working
output increases.

Eri

[eridanus]

El mi�rcoles, 23 de abril de 2014 02:39:57 UTC+1, Roger Shrubber escribi�:

> Richard Norman wrote:
>
> > On Tue, 22 Apr 2014 20:16:01 -0400, Roger Shrubber

> > ------------------ snipped -------------

Then, the problem is not with cycling, but with walking or running?
I will repeat myself again. Walking is rather natural for humans,
and we rarely reach a peak of inefficiency. But it can be reached.
I am not an expert in sports but I have some intuitive intelligence
about this and less "memorized artifacts" that often are wrong.
In the case of walking, the limit is mostly not on the rate of output
for a discreet time, but on the time expending some critical effort
for many hours. But for a person not trained at physical efforts,
to walk up some steep street, like some city situated on a hill
can be a very strenuous effort and the person is expending a lot
of effort disproportionate to the the output.
But even on level ground, a brisk pace of walking cannot be
maintained for some ten hours, to put an example, and the
energy consumed began to be greater in the last five hours
than in the first five hours, when started the walk. The same
can be said for running. I am not going to enter farther into
this argument. If you want to be sure, you must look for some
reliable sources of information about "Efficiency in walking
and running". For my part I do not need to look farther for
this question is rather trivial and do not deserve a waste of
time for a silly dispute.
Eri

[eridanus]

El viernes, 25 de abril de 2014 13:09:15 UTC+1, Richard Norman escribi�:

> On Fri, 25 Apr 2014 01:38:47 -0700 (PDT), eridanus
>
> <leopoldo...@gmail.com> wrote:
>
>
>

> >El mi�rcoles, 23 de abril de 2014 01:54:01 UTC+1, Richard Norman escribi�:

I was doing some elemental math on efficiency physical
exercise.
I found a table where it shows that walking is more efficient
than running for the same speed, and even the graph shows
that running is less efficient than running even if it improves
something as it goes more rapid.
I can show you the link of this table if you are interested.

Then, as I was intuiting, the question of running is improving
for a while with some distance like 200 meters, and later the
speed is getting down as the distance is larger.

I had not find any graph to prove that, then I made one myself
by simply by watching the later different sportive records on
running. I was looking at the latest records for different races
and here are some results.

example:
100 m. 9.78 sec. speed 36.8 km/h
200 m. 19.32 37.26 Km/h
400 m. 43.18 33.34 Km/h
800 m 1:40.9 28.54 Km/h
1,000 m 2:11.9 27.29 Km/h
1,500 m 3:26 26.21 Km/h
Marathon 2013 20.51 Km/h

Now for the best record of the Olympic marathon in 2013 in Berlin
distance 42.29 Km time of the record... 2:03:23 that is 7403 seconds
then translated as speed in Km/h
42,290/7403=5.699 m/s that is 20.51 km/h (average)

I think this argument proves that as the time is prolonged, the
the muscular efficiency of the athletes lowers for times
longer than 200 or 300 meters.
This for well trained athletes. For common folks is much worse.

eri

[Richard Norman]

On Fri, 25 Apr 2014 13:26:50 -0700 (PDT), eridanus
<leopoldo...@gmail.com> wrote:

>
>El viernes, 25 de abril de 2014 13:09:15 UTC+1, Richard Norman escribi�:

>> On Fri, 25 Apr 2014 01:38:47 -0700 (PDT), eridanus
>>
>> <leopoldo...@gmail.com> wrote:

>> >El mi�rcoles, 23 de abril de 2014 01:54:01 UTC+1, Richard Norman escribi�:
>> <snip>

<snip to focus on the point>

>> >> However I said that the total
>> >> energy you spend to move, say, one mile does not depend on how fast
>> >> you travel that mile within reason. That is, walking, jogging or
>> >> running are all quite similar.

>> >I thought this was not the question, but the energy consumption of the
>> >living being doing the work.
>> >I am not an expert in the physiology of the work, or ergometry I suppose
>> >it is called; but I do not believe you are either.
>> >So, I postulated from my ignorance, that... <snip>
>
>> That the amount of physical work done is zero shows that the actual
>> energy consumption of the living being has no connection with physical
>> work.
>>
>> I am not expert in the physiology of the work but happen to be
>> extremely knowledgeable in it and have taught this stuff for several
>> decades. I am not postulating from ignorance but rather citing the
>> results from people who are expert and who have studied this
>> extensively. Before writing my posts I consulted a variety of texts
>> and verified that the graphs showing actual experimental data on
>> metabolic rate of humans at various speds and gaits demonstated what I
>> was saying.

>I could easily look for papers also in the net that would confirm my
>"imaginative speculations". I was saying something reasonable, but
>you had only pointed to other sources "you say to know" but do not
>make them explicit. What sources are those, but just that you knew
>them. You were presenting some indirect authority. It was not just
>you, but some in authority the permitted you to challenge my argument.
>
>So, far in a mere couple of minutes, I had found two papers in pdf
>that favor my thesis, that exist a differential of muscular efficiency
>for different outputs of work.

Again you are talking about something very different from what I
referred to. You are still back to the total energy consumption and
the relative efficiency of different types of activity. On the other
hand, my comments were specifically directed at one topic and one
topic only: the amount of metabolic energy necessary to travel a given
distance regardless of speed.

I no longer own most of my former very extensive library from when I
was actively teaching this material. However I did refer to
"Exploring Biomechanics" by R McNeill ALexander, 1992 and especially
the fiture on page 25 which shows the energy/distance cost for various
speeds of running from 1 to 4 m/sec (2 - 9 mph). This varies less
than 3% over the range. The value for walking does change with speed
but at a comfortable pace agrees nicely with the value for running.

I also referred to "Eckert Animal Physiology" 5th edition of 2002 and
to the extensive section "Energetics for Locomotion" on pages 681-688.
For many years and through many editions, this was the textbook I used
for teaching animal physiology. In particular, Figure 16-13 is on the
metabolic rate during locomotion.

There is an extrememly large literature on the biomechanics and
bioenergetics of muscle contraction and of movement and of locomotion.
You may have been saying something reasonable about an outside point
that I had no interest discussing -- it is hard to tell because your
posts ramble around from topic to topic so much. That is irrelevant.
What I do declare is that I know something about the energetics of
locomotion and my original point that, over a reasonable range, the
cost of moving a given distance does not substantially depend on how
fast you cover that distance.

[eridanus]

El domingo, 27 de abril de 2014 00:32:44 UTC+1, Richard Norman escribió:
> On Fri, 25 Apr 2014 13:26:50 -0700 (PDT), eridanus
>
> <leopoldo...@gmail.com> wrote:
>
>
>
> >
>

> >El viernes, 25 de abril de 2014 13:09:15 UTC+1, Richard Norman escribi�:

>
> >> On Fri, 25 Apr 2014 01:38:47 -0700 (PDT), eridanus
>
> >>
>
> >> <leopoldo...@gmail.com> wrote:
>

> >> >El mi�rcoles, 23 de abril de 2014 01:54:01 UTC+1, Richard Norman escribi�:

I was referring to the efficiency per distance, in terms of velocity.
There is an optimal pace for walking, or running, that depends on the
speed and the length of the legs of the walker, or runner. Other variable
is how muscular is the person, etc. Then, there are differences among
the different walkers or runners. But walking is by far most efficient
than running. For the same speed, the runner is consuming some 70% more
than the walker for the same speed. It is evident when you observe the
the athlete breathing. Running requires a lot more oxygen.
I had observed a few pages
in one of them that is more clear, present expenditures of energy in
calories/mile/100lbs) for both walking and running
for speeds 3 3.5 4 4.5 5
walking 52 50 58 65 73
running 89 87 85 84 83

this data are in a page
http://www.exrx.net/Aerobic/WalkCalExp.html
this is not scientific paper, but surely the data is taken for some
scientific paper they do not tell.
There is an optimal speed for walking, than can be a little different
for different persons according to the length of his legs.
When walking the body is going some up and down some hight that depends
on the length of the step.
In running this up and down is higher. The steps are larger than in
running and that makes the difference.
Mechanical work and efficiency in level walking and running

G. A. Cavagna and
M. Kaneko*

+ Author Affiliations

Istituto di Fisiologia Umana dell'Università di Milano
Centro di Studio per la Fisiologia del Lavoro Muscolare del C.N.R., 20133 Milano, Italy

in this article of Cavanna and Kaneto

Abstract

1. The mechanical power spent to accelerate the limbs relative to the trunk in level walking and running, Ẇint, has been measured at various `constant' speeds (3-33 km/hr) with the cinematographic procedure used by Fenn (1930a) at high speeds of running.

2. Ẇint increases approximately as the square of the speed of walking and running. For a given speed Ẇint is greater in walking than in running.

3. In walking above 3 km/hr, Ẇint is greater than the power spent to accelerate and lift the centre of mass of the body at each step, Ẇext (measured by Cavagna, Thys & Zamboni, 1976b). In running Ẇint < Ẇext up to about 20 km/hr, whereas at higher speeds Ẇint > Ẇext.

4. The total work done by the muscles was calculated as Wtot = ǀWintǀ + ǀWextǀ. Except that at the highest speeds of walking, the total work done per unit distance Wtot/km is greater in running than in walking.

5. The efficiency of positive work was measured from the ratio Wtot/Net energy expenditure: this is greater than 0·25 indicating that both in walking and in running the muscles utilize, during shortening, some energy stored during a previous phase of negative work (stretching).

6. In walking the efficiency reaches a maximum (0·35-0·40) at intermediate speeds, as may be expected from the properties of the contractile component of muscle. In running the efficiency increases steadily with speed (from 0·45 to 0·70-0·80) suggesting that positive work derives mainly from the passive recoil of muscle elastic elements and to a lesser extent from the active shortening of the contractile machinery. These findings are consistent with the different mechanics of the two exercises.
In this article of Cavagna and Kaneto it is clearly seen that the consume
of energy grows as a function of squared speed.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1283673/pdf/jphysiol00809-0192.pdf
this is the article
In the figure 2 presents a graphic both logarithmic and lineal of the
consumption of energy as a function of speed.

An article of Scientific American
<http://blogs.scientificamerican.com/scicurious-brain/2012/01/02/walking-or-running-efficiently-your-locomotor-muscles-might-not-agree/>

it says in the first paragraph:
Humans walk well. More to the point, we walk EFFICIENTLY. As we evolved to walk upright, we also evolved to do so with great economy, expending fewer calories at an optimal walking pace, but then expending more calories when we either speed up or slow down. We also may be economically efficient runners as well as walkers, we’re average for mammals, but our long legs and ability for those legs to take repeated strain suggests we may be on the efficient end of primates (and we’re some of the BEST long distance runners on the planet, so we can preen a bit over that one). The jury is still out on running, but as far as walking goes we are the most efficient at a moderate speed (roughly 5 km/hr, or 3.1 miles/hour for men, a relatively brisk walk of 20 min a mile).

Then the article mentions, Carrier et al. “The musculoskeletal system of humans is not tuned to maximize the economy of locomotion”. PNAS, 2011.
<http://www.pnas.org/content/early/2011/11/02/1105277108>
The abstract says:
Humans are known to have energetically optimal walking and running speeds at which the cost to travel a given distance is minimized. We hypothesized that “optimal” walking and running speeds would also exist at the level of individual locomotor muscles. Additionally, because humans are 60–70% more economical when they walk than when they run, we predicted that the different muscles would exhibit a greater degree of tuning to the energetically optimal speed during walking than during running.

I suppose the article is comparing both systems of moving at the same speed.

Of course, walking has an optimum speed of moving. For greater or lowers
speeds some efficiency is lost.
in thus article: <http://www.pnas.org/content/108/46/18631.full>
there is a graphic for maximum efficiency of different muscles both
for running and walking. You can see that this is not a lineal function.

Summing up: Dear, I cannot believe you were thinking that a biological
machine can be equally efficient at all speeds.

The data I had been able to watch are factual data measured in some
laboratory conditions. My opinion was simple based on an elemental
intuition. The energy consumed is in general a function of the speed.
For biological systems work on little impulses with each step or so.
It is not like a rocket in space, that once it had been put at some
speed it remain so forever unless some collisions with other matter
would alter this velocity and sense of direction. The satellites in orbit
tend to loose speed due to collisions mostly with molecules of air from
the earth and other artifacts; like micrometeorites, or other; debris from
some broken artifacts in orbits, etc.
Eri

[Richard Norman]

On Sun, 27 Apr 2014 04:14:09 -0700 (PDT), eridanus
<leopoldo...@gmail.com> wrote:

<snip>

> Istituto di Fisiologia Umana dell'Universit� di Milano

> Centro di Studio per la Fisiologia del Lavoro Muscolare del C.N.R., 20133 Milano, Italy
>
>in this article of Cavanna and Kaneto
>
>Abstract
>

>1. The mechanical power spent to accelerate the limbs relative to the trunk in level walking and running, ?int, has been measured at various `constant' speeds (3-33 km/hr) with the cinematographic procedure used by Fenn (1930a) at high speeds of running.
>
>2. ?int increases approximately as the square of the speed of walking and running. For a given speed ?int is greater in walking than in running.
>
>3. In walking above 3 km/hr, ?int is greater than the power spent to accelerate and lift the centre of mass of the body at each step, ?ext (measured by Cavagna, Thys & Zamboni, 1976b). In running ?int < ?ext up to about 20 km/hr, whereas at higher speeds ?int > ?ext.
>
>4. The total work done by the muscles was calculated as Wtot = ?Wint? + ?Wext?. Except that at the highest speeds of walking, the total work done per unit distance Wtot/km is greater in running than in walking.

Sorry to be so long responding. I actually do have things beyond
talk.origins in my life and can't keep up especially with technical
material that requires some concentration and effort.

I am very happy to see that you are looking into actual scientific
studies to support your position and not just you own perceptions
which, though often enough valid, are just as often misleading. (I
don't mean specifically your perceptions -- it is true for everyone.)

Nothing you cite here disagrees with what I claimed. First I have not
at all discussed the efficiency of muscle contraction or biological
activity except for writing: "Even when you do substantial amount of
work in physics terms, the efficiency at which you do it (the number
of kcal of energy you burn) can vary widely. So only 20% or so of you
energy expenditure actually goes into doing work." That is, I am very
well aware of the inefficiencies in muscle contraction and the wide
variability of that efficiency.

You found and cited two scientific studies about this topic. I did
indicate "There is an extrememly large literature on the biomechanics

and bioenergetics of muscle contraction and of movement and of

locomotion." The Scientific American article and the associated paper
in PNAS by Carrier et al. is about the fact that no one individual
muscle in the body operates at its "highest efficiency" over the
range of speeds involved in running or walking. Some are more
efficient at low speeds, others at higher speeds. There is really not
much discussion about the overall expenditure of energy by the whole
body as a function of speed. The paper indicates: " In contrast,
although humans appear to have optimal running speeds (7), the COT is
relatively independent of running speed compared with horses. This
independence results in humans being not as economical at their
optimal running speed, as would be the case if all muscles were
tightly tuned to that speed. However, it also means that we have
relatively good economy when running at both slow and fast speeds,
presumably broadening the range of sustainable speeds." In other
words, we have pretty much the same efficiency over a wide range of
speed, just what I was arguing.

That paper also says "The energetic cost to travel a given distance,
the cost of transport (COT), has long been known to strongly depend on
walking speed in humans (1, 2). The cost is minimized at intermediate
walking speeds of 4.5�5.4 km�h-1 (1.25�1.5 m�s-1) and rises rapidly as
speed increases above or decreases below this optimum. In contrast,
the metabolic cost to run a given distance is generally recognized to
be independent of speed in humans (2�6). Recently, however, a
reevaluation of the COT in running humans has shown that humans also
have energetically optimal speeds when running (7)" This statement,
up to that last sentence, is exactly what I wrote, both about the
variation in energetics of walking with speed and the constancy of
running. The paper mentioned in the last sentence was published after
I retired. However reading that paper changes nothing. The problem
relates to failing to include the general caost of living (basal
metabolism) to consider the EXTRA cost of locomotion beyond the basal
rate. As I already indicated, if you use simple metabolic rate
measurements to calculate the efficiency of locomotion you find that
if you go at a speed of zero, you still have a non-zero metablic rate
so the cost per mile to go nowhere is infinite! The result in the
paper mentioned as showing a U shaped curve of energy per kilometer vs
speed disppears when you consider the extra energy per kilometer.

There is a small variation in the energy cost of locomotion with
distance when running at different speeds but it is of only a few
percent whereas the metabolic rate varies over a factor of 4 or more
(400%). So I indicated that the variation with speed is not really
consequential. The U-shaped curves in that new paper, even without
removing the basal metabolism, only vary about 5% or less over the
speed range considered. There is a technical "optimal speed of
running" but not one that has any significant effect considering all
the variabilities that are far larger in real human performance.

The graphs in that non-scientific citation you found agree exactly
with what I wrote except my data show the walking curve to more
closely agree with the running data. The cost of walking, once again,
varies with speed while the cost of running does not once you take
into account the cost of living (use of energy when you don't move at
all). The cost of walking rises steeply with speed which is why at
slower speeds we walk but at faster speeds we run. The crossover
point occurs at what we consider "fast normal" walking speeds. Again,
that is just what I have claimed all along. There really is no
significant difference in the extra cost of locomotion (above resting
or basal metabolism) between walking at a comfortable pace and running
either fast or slow over a very broad range. You do get variation at
the extremes, both slow and fast.

[eridanus]

El mi�rcoles, 30 de abril de 2014 19:33:46 UTC+1, Richard Norman escribi�:

Ok, Richard, no problem. It's ok.
Eri