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View Full Version : Hiking is twice as effecient as driving a car!



magneto
03-01-2012, 17:01
So I have time off / plane tickets to go down to Atlanta in September and hike for at least 30 northbound along the AT.

I was thinking about how much food I would need and I came to an interesting conclusion:

5000 calories per day for 30 days = 150,000 k calories = ~594 k BTUs = ~627,000 k joules = ~ the amount of energy in 5.2 gallons of gasoline.

My car gets 33 miles per gallon highway, so that means I could go about 171 miles. I am sure I will walk further than that on my AT trip (maybe twice as far), so it looks like not only is hiking better for your health, it is more efficient than driving as well!

Put another way, if all that energy were concentrated in a single Twinkie, the Twinkie would be 91 feet wide, by 325 feet long, by 125 feet wide and would weigh 93 pounds! And to quote someone famous, "That's a big Twinkie!".

magneto
03-01-2012, 17:07
Of course I can't edit my posts - that should be 30 days and the Twinkie would be 91 feet wide, 325 feet long and 125 feet high!

BobTheBuilder
03-01-2012, 17:32
Hmmmm - 150 k calories in a Twinkie means 1000 twinkies is 150,000 k calories. With dimensions of 1" x 1" x 4", a Twinkie has a volume of 4 cubic inches. 1000 of them would have a volume of 4000 cubic inches, or 2.3 cubic feet. Your mythical super-Twinkie is really only a Twinkie cube 1.3 feet, or 16 inches on each side.

That's not that big of a Twinkie.

While I'm at it, if you had to carry the same pack weight as your car, maybe about 3300 lbs, you would make a lot less miles. I'm just sayin'.

magneto
03-01-2012, 17:44
I think you are right on the Twinkie example. 1000 Twinkies is a lot though. You could also eat ~255 Big Macs (590 cals each).

RWheeler
03-01-2012, 17:48
It's pretty standard to see energy efficiency drop as speed efficiency rises. That's why automobiles are used, they're terribly inefficient in terms of energy. Do a comparison to something like a motorcycle and it'd be a totally different situation (see Bob's weight comment).

magneto
03-01-2012, 18:04
I know. This was just a whimsical thing. I guess I could have just drank the 5 gallons of gas and been done!

RWheeler
03-01-2012, 18:24
That'd be a poor way to waste $20, though.

magneto
03-01-2012, 18:30
It would be a lot cheaper than buying and eating 1000 Twinkies. The Twinkies just wouldn't kill you as fast...

lush242000
03-01-2012, 19:01
Not really a fair comparison. Your car probably weights over 1500 pounds, or roughly ten times your weight. But fun to think about.

magneto
03-01-2012, 19:10
It is interesting to think about how many calories we use to produce a single calorie of food for human consumption. For my whole trip, 150K calories seemed like a lot. I read somewhere that it takes about 10 calories of energy to produce/transport one calorie of food for human consumption. That 30-day 150K requirement then becomes 1.5 million.

Before I started hiking, I consumed 5000 calories per day and weighed just over 400 lbs. Now that I hike a lot, I weigh 1/2 as much, but need to consume as many calories while hiking!

rocketsocks
03-01-2012, 19:24
Wow,and I thought I had a lot of time on my hands,turns out I'm just not that smart.And besides.My car is on a low lead diet,hamburgers make her belch and buck.

JAK
03-01-2012, 20:15
It would be interesting to know who has the record for hiking the AT on the least number of calories.

Rasty
03-01-2012, 20:58
It would be interesting to know who has the record for hiking the AT on the least number of calories.

Probably the youngest to ever finish the trail would be my guess.

theoilman
03-01-2012, 21:24
Since this isn't in the hiking-humor forum (I had to scan back to the top to check) I have to wonder what kind of engineers some of you are to come up with these calculations.

How heavy is that 'super-twinkie'? By my calculation 1 ounce on my back translates to 200 lbs of pounding on my feet per mile hiked, or 2000 lbs in a 10 mile day. (Varies considerably according to the length of your pace and speed of hiking.)

magneto
03-01-2012, 21:45
I miscalculated the twinkie thing badly. Sorry. The Twinkie would be much smaller than I said. My dumb-ass mistake.

burger
03-01-2012, 23:02
Your math is off. If you were in a coma, you'd still burn about 2000 calories a day (maybe less if you weren't moving at all). So the hiking itself only uses about 3000 calories a day. When you compute it like that, hiking is even more efficient compared to driving.

Feral Bill
03-02-2012, 00:11
What's the deal with the Twinkies? The proper unit of food energy is the Snickers.

magneto
03-02-2012, 09:03
Right "Lots and lots of Snickers."

1 snickers bar = 277 k calories. 150K k calories / 277 = ~542 snickers bars. 1 snickers bar = 2.0z. 542 * 2 / 16 = ~68 lbs of snickers bars.

I would bring an extra 20 lbs to fling during the approach.

JAK
03-02-2012, 09:13
I belive the proper SI unit is a French pain au chocolat.

takethisbread
03-02-2012, 09:31
What's the deal with the Twinkies? The proper unit of food energy is the Snickers. that's what I was thinking.

JAK
03-02-2012, 09:36
It would be interesting to know who has the record for hiking the AT on the least number of calories.
Probably the youngest to ever finish the trail would be my guess.I was thinking that also, except they use calories for growing. Then I was thinking maybe Jennifer Pharr Davis, although she was supported. Running is somewhat less efficient than walking, but perhaps not in her case, and she would have an advantage in doing it in fewer days so there would be less "rest of day" type overhead. Anyholyw, I know its not her cup of tea, but I'll bet if she want to carry all her own food and do her own resupply, and go at her most energy efficient pace rather than her fastest pact I would think she would cover the trail in alot fewer calories than most people. Someone like her but smaller than she is could do better I suppose, in terms of using less energy that is.

Total Calories = Base Calories + Hiking Calories
Base Calories = Lean Body Weight x Days x Base Efficiency Factor
Hiking Calories = Total Weight x ( Miles + 10% x Gain ) x Hiking Efficiency Factor

Not sure of trade off in efficiency in running vs walking when terrain and base calories is considered. Probably a combination of running and walking, walking up hills for sure. Running at times, especially on gentle down slopes. Jennifer probably does all that naturally anyway, but when optimizing for total energy efficiency over distance she would probably go somewhat slower, and more hours per day maybe. Not sure.

The other thing to optimize would be resupplies, especially if you didn't do any shuttles.
Has anyone ever hiked the entire trail without support, or hitching rides for resupply?

magneto
03-02-2012, 10:49
It's all in your point of view: "Ghostbusters" or "A Walk in the Woods".

BobTheBuilder
03-02-2012, 11:19
Maybe we need a "Bored Engineers Calculating Silly Things" category. I would be all over that. I was just getting ready to measue a snickers' dimensions, anyway, so we could see how big the 30-day cube would be. Then we could cross-reference that to one of the gear guide forums and identify the proper size pack. Since packs are usually sized in liters, there is a whole other Imperial-to-SI units conversion we could perform.

Man, I'm bored.

magneto
03-02-2012, 11:32
That was my screw-up with the Twinkie...

I don't think you would have to carry all the Snickedrs -- I am sure they have some at Neel Gap...

Feral Bill
03-02-2012, 12:15
I belive the proper SI unit is a French pain au chocolat.
Next you'll have us working on becoming 3500 kilometerers.