I was just reading something interesting regarding human metabolism and why it's so easy to gain weight. Since calories is a measurement of heat, it's easy to determine the calories in a gallon of gasoline. Once we've done this we can represent human energy usage in miles per gallon. An auto that gets 30 MPG is considered to be very good efficiency. A 150 pound man gets well above 300 miles per gallon, running and using his mechanically inefficient legs! Using a device to convert linear motion into rotary, such as a bicycle, a 150 pound man will get around 1200 miles per gallon! Even considering an efficiency car weighs ten times as much, that's still quite a differance! Especially considering that many with weight problems can rate well below average metabolisms. We're too energy efficient for our own good with the food we produce!

I thought it was kind of interesting.

[img]graemlins/monkeydoo1.gif[/img]

(brilliant smiley :D )

As to answer your post, Ken, it was very interesting indeed..
Where did you find it?
Or maybe you've come up with it yourself?

That is very interesting.

I only get about 12mpg now because I used to have my oil changed at Kentucky Fried Chicken. [img]graemlins/hehe.gif[/img]

Oh bollocks, perhaps I should give up ordering beer by the gallon then [img]graemlins/biglaugh.gif[/img]

Seems to me, that according to my highschool physics experiments...(so many decades ago) that either humans have metamorphosed into some kind of super being or you made a mistake....Humans and most other life forms are NOT efficient mass converters. A human consumes a large amount of fuel of which almost 90% is expelled as waste, and while you may not have to eat a gallon of material to walk a mile, you ARE consumeing energy (from your stores of sugars and fats) that took years of eating mass quantities of materials. Plus you did not take into account how much fuel was expended in makeing the food you ate...while cars are not very efficient, People are even less so.

<blockquote>quote:</font><hr>Originally posted by MagiK:
Seems to me, that according to my highschool physics experiments...(so many decades ago) that either humans have metamorphosed into some kind of super being or you made a mistake....Humans and most other life forms are NOT efficient mass converters. A human consumes a large amount of fuel of which almost 90% is expelled as waste, and while you may not have to eat a gallon of material to walk a mile, you ARE consumeing energy (from your stores of sugars and fats) that took years of eating mass quantities of materials. Plus you did not take into account how much fuel was expended in makeing the food you ate...while cars are not very efficient, People are even less so.<hr></blockquote>

A gallon of gasoline has over 23 Kcal (23000 calories). Enough energy to keep the average human going for a fortnight. Let's not also forget that petroleum is made from the remains of the organic life you are calling inefficient. A sizable portion of which is not usable as auto fuel and therefore wasted in that respect when the petroleum is distilled and refined. When I said efficient, I meant in comparison to the automobile, not a fusion reaction.

Not disputing the energy rating of petrol that you mentioned, I just think you are missing HUGE amounts of wastage that goes into creating the fuel for the human bod. And the conversion of that fuel by the human body is also quite inneficient as well..everything from heat disapation to the mass consumed to fuel created is way low on the efficiency scale. (PS I knew where the petrochemicals come form [img]smile.gif[/img] )

<blockquote>quote:</font><hr>Originally posted by MagiK:
Not disputing the energy rating of petrol that you mentioned, I just think you are missing HUGE amounts of wastage that goes into creating the fuel for the human bod. And the conversion of that fuel by the human body is also quite inneficient as well..everything from heat disapation to the mass consumed to fuel created is way low on the efficiency scale. (PS I knew where the petrochemicals come form [img]smile.gif[/img] )<hr></blockquote>


Hey, I just read my own post. Sorry if I sounded a bit grumpy Magik. I havn't had my coffee yet. ;) Almost any reaction that oxidizes produces lots of heat as a by product. Excess heat is of course wasted energy. Oxidation is the primary reaction used for energy by our bodies, civilization, and life on the planet in general, isn't it? When you say inefficient, what are you comparing to?

Why Im comparing it to total conversion of course ;)

While I admit that the human body and any other higher life form for that matter is a marvel of engineering and nothing to sneeze at...its just not an efficient scheme..I don't remember the figures but the total amount of surface area on the planet needed to sustain a single person is quite large. Not being an engineering graduate I lack the proper mathh to explain what I actually can remember from lectures concerning this very topic. In the end we as living creatures use only a small portion of the food we eat..the rest is wasted...we take in more than we would if we were more efficient energy converters...


And as for being grumpy [img]smile.gif[/img] I didnt notice any grumpin in there [img]smile.gif[/img] could be that I am too tired and not quite as preceptive as I could be too [img]smile.gif[/img] (long night rebuilding my game computer [img]tongue.gif[/img] )