Brad Ideas - Holy cow: Walking consumes more gasoline than driving! - Comments

Wasted food

brad — Sun, 17 Jan 2010 19:31:43 -0800

Well, other than what you have said about some people wasting more food than others (which is difficult to quantify) the amount of food wasted does not affect the calculations about how fuel-inefficient American industrial agriculture is, which is what this article is about. It is not about bicyclists.

What about the food we waste?

Oskar — Sun, 17 Jan 2010 05:45:26 -0800

You seem to assume that we realize all the calories we get from the agribusiness, but a lot (more than 50% according to some UK sources) is wasted (so most of it ends up in landfill producing CH4, and needs more energy to be refrigerated/waste-managed).

It is my impression, but a serious study should be conducted, that walkers and cyclists tend to finish-up what's on their dishes, while drivers are more prone to "waste" it. Also, driving to large supermarkets make people overshop, for carrying is not a problem; and overshopping is one of the primary reasons behind excessive domestic waste (in the UK alone, each day 5000 chickens are thrown in the bins for being past their sell-by date).

I say all those things

brad — Sat, 12 Dec 2009 02:16:28 -0800

However, the real point is the efficiency of agribusiness, not about the density of cities at all.

That is discussed in detail

Mark Denison — Fri, 11 Dec 2009 18:38:21 -0800

Brad, I understand now your point that the comparison the gas energy content of food is valid. But you are missing my second point. People with a higher body mass index (BMI) burn more calories at rest. As one puts on weight, the amount of calories that you can consume without gaining more weight increases. If cycling causes someone to maintain a lower body weight than they would without cycling their baseline metabolism will burn fewer calories all the time. The savings in calories will offset some and possibly all of the calories burned cycling (or any other exercise).

Professional cyclists in a stage of the Tour de France will burn 4,000 to 5,000 calories pushing their daily consumption up to 7,000 calories or more. Here your mpg calculation is valid and then some (you should even add in the team cars carrying wheels and spare bikes and the helicopter flying overhead with the TV camera). But a commuter who bikes 12 miles round trip every day burns only an extra 400 calories. A man who weighs 150 lbs with a normal BMI may increase his calorie intake say from 2400 calories per day to 2800 calories per day and maintain his body weight. However if the same man were to be 30 lbs overweight (probably average these days) he would have to consume 2880 calories per day to maintain his body weight. This is how cycling to work could mean no net increase in calories and thus no fossil fuel use. And it is an accurate observation that the average cyclist weighs 30 lbs less than the average non-cyclist.

There are compelling reasons to exercise that outweigh any concern about the environmental consequences of food calories. Being sedentary contributes to many diseases and reduces your lifespan. The obesity epidemic suggests that it is not normal for sedentary individuals to consume only a maintenance level of calories.

On another note, walking and cycling (and mass transit) are better for the environment because people who walk and cycle live in denser cities an enable cities to be denser. Above all automobile use leads to more miles traveled and even if the energy use is no worse per mile the increased distances result in more GHG released.

The real point of your analysis (which really is brilliant) is that cities need to become denser. Outside the market forces that direct development, communities need to rethink policies that promote low density automobile dependence - things like parking requirements, setbacks, minimum lot sizes, street widths and the like.

That is discussed in detail

brad — Mon, 07 Dec 2009 11:02:49 -0800

And it is also not true that anybody does not replace every calorie consumed with one eaten. If you don’t do this you lose weight, and eventually die. Everybody.

This compares fuel in cars to fuel in tractors and machinery, plus fuel used to make fertilizer. It’s fuel to wheels for both.

yes! but what is the fuel to wheels energy in gas

Mark Denison — Mon, 07 Dec 2009 07:51:32 -0800

Fascinating analysis. As a cyclist, every instinct in me is to take your analysis apart and I see several people have tried and mostly failed. I gave up until I thought of this. What is the fuel to wheels energy cost in a gallon of gas? Surely just as food takes a lot of energy to produce and transport, so does gasoline. Are you comparing apples to oranges when you measure the energy content of extra food calories based on the physical energy content of a gallon of gas? Don't you have to compare to the energy content of the gallon of gas plus the energy it takes to produce and deliver that gas to the consumer?

I would also add that as cyclists are slimmer on average than the general population that cyclists do not replace every extra calorie burned with one more eaten. Slimmer people burn fewer calories at rest so if cycling does in fact contribute to maintaining lower body weight then the net calorie consumed as a result of cycling could be much lower than your assumptions even negative.

Sorry, I just woke up. At 20

Sparrow — Mon, 28 Sep 2009 20:40:56 -0700

Sorry, I just woke up. At 20 mph, those 20 minute vehicle figures are for 6.67 miles.

One miles would be:

car 2.39
police car 4.65
motor scooter or motorcycle 7.05
bus, heavy truck or tractor 9.45
heavy machinery 23.4

I guess driving heavy machinery isn't quite the workout it first appeared to be.

According to DietPower (the

Sparrow — Mon, 28 Sep 2009 20:38:14 -0700

According to DietPower (the nutrition and exercise software I use):

For 20 minutes of driving the following vehicles, the average human burns the following amount of calories above those that would have been burned in watching television for 20 minutes:

car 16
police car 31
motor scooter or motorcycle 47
bus, heavy truck or tractor 63
heavy machinery 156

converting this to per-mile would be tricky because the above vehicles travel at different speeds. However, since 20 mph is a fine rule-of-thumb for in-town driving, those could be considered rough per-mile figures as well.

For comparison within the same software, 1 mile of each of the following activities burns the following amounts of calories above television watching (or other basal metabolic-level activities):

walking 1.5 mph (40 minute mile) 63
walking 2 mph (30 minute mile) 70
walking 2.5 mph (24 minute mile) 75
walking 3 mph (20 minute mile) 77
walking 3.5 mph (17 minute mile) 79
walking 4 mph (15 minute mile) 94
(naturally these figures go up if one is walking uphill, in snow, etc)

Bicycling:
light (under 10 mph) 28
leisurely (10-11.9 mph) 43
average (12-13.9 mph) 51
intense (16-19 mph) 59
competitive (20 mph or faster) 70

Personal surprises: I didn't realize driving heavy machinery was such a workout.

I was stunned at first that a mile of furious pedalling burns the same calories as a mile of slowly strolling but then I thought about the fact that a mile at 20 mph on a bicycle is 3 minutes while a mile at 2 mph on foot takes ten times longer thus furiously pedalling is a more efficient exercise as it burns calories ten times as fast. (But if, like me, one only gets exercise when one needs to go someplace, walking might be more exercise-efficient while more time-consuming.)

well to tank cost for gasoline

brad — Sat, 18 Apr 2009 09:01:36 -0700

The figures I have read suggest about 82% of the “in the well” energy makes it to the tank, the rest used in refining, drilling and transport.

I don’t have the figures for coal. It’s worse for tar sands syncrude of course. You’ll have to search for exact cites, should not be too hard.

Note however that this number plays a limited role in comparing the moped and the fuel cost of agriculture. The fuel in the tractors has the same cost of refining and transportation as the fuel in the mopeds. However, much of the fuel cost is in fertilizer which is made from natural gas, and it has a different cost of extraction (lower) than the motor fuel, and I don’t know the cost of conversion to fertilizer.

Could you please contact me?

Nick — Fri, 17 Apr 2009 21:01:44 -0700

I'm writing an article about the behind-the-scenes energy costs of cycling versus riding a moped. I know that each Calorie of food takes about 10 Calories of gasoline to produce/deliver/store, but how many Calories of gasoline does it take to produce/deliver/store a Calorie of gas? that's the final figure I need for my article-- thanks so much!

So dieting is green

Dodger — Sun, 12 Apr 2009 00:31:37 -0700

I'm consuming an average of less than 1000 calories per day (I'm supposed to be wating 1250, but I'm being hardcore and don't give me crap about it), in an attempt to lose weight.

The idea of weight loss is not to consume more calories to make up for the exercise, but to add the exercise to increase the caloric deficit.

Therefore I'm *not* eating more, and I'm walking more and driving less so that my iPhone makes my numbers really low, and in a day or two my scale agrees.

In this case, it would seem that exercise *is* green, since I'm doing the exercise *and* eating less than normal anyway.

Therefore, everyone should diet and get thin.

There's just one thing more to factor into the possible side effects of this. If everyone lost weight and started looing really good, how much energy is comsumed by the manufacturing of the higher quantities of condoms that would then become necessary?

Fossil fuel intensity isn't simple

Anonymous — Tue, 24 Mar 2009 17:22:16 -0700

Brad, if you read the article you cite it is clear that the actual fossil fuel intensity of agricultural styles varies significantly from society to society. The authors of that paper make the point that North American/Australian agricultural systems produce 1 to 2 times as much energy in food as is consumed as fossil fuels in its production (ie; it is efficient) whereas in most European agricultural systems, and in Japan, the system is highly inefficient with multiples of input fuel energies over output energies of food energy - in other words, ineffienct. While African agronomy is fossil fuel efficient (30:1 food energy output vs fossil fuel inputs) this is relatively speaking not very land-efficient nor efficient for human capital. ie; one would have to argue that human labor in the food chain in low-technology countries replaces fossil fuel energies significantly.

The fact is also that, whilst beef production in America is done on cereal feeds in feedlots and is inherently inefficient, the American vegetarian is actually more fossil fuel efficient than the Chinese average person because American fertiliser is coined from natural gas and Chinese from coal. So one can argue that the most ethical and environmental choice is to become an American citizen and eat a non-organic American vegetarian diet (given that organic farms are less energy efficient than non-organic broadacre commercial farms).

Going down this route, you can reduce your fossil fuel intensity per calorie to as little as a sixth of a Japanese person, and perhaps half of a Chinese person. That tends to throw a spanner in the works. Indeed, one thing this analysis tends to conclude is that the best way for American people to reduce envirnmental impacts of fossil fuel utilisation in agriculture is to, in fact, subsidise and encourage Chinese uptake of natural gas nitrogenation as opposed to using coal. This efficiency alone would reduce carbon impact and input energy intensity dramatically.

walk vs. drive discussion

dave — Mon, 16 Mar 2009 09:16:55 -0700

OMG people! You're beating the details to death and it's nothing but mental masturbation. And you're not going to be any more satisfied by this nit-picking either.

The point that using the least energy to achieve any task is not always obvious, but not even readily determinable, is made and clearly so. Let it go. Grasp the point made, and make your choices. Don't argue the details.

Will the world's use of energy change one iota if you make via your discussion even a 40% correction to the numbers used? No. Will YOU drive to work instead of walk, or the other way 'round, depending on the numbers? I doubt it. Our average commute in this country is just too far to walk, so you won't, no matter how much less energy it uses.

Now, why don't some of you geniuses apply your turgid grey matter to convincing the world's population that they should give a crap? THAT task would be worth all the mental energy you're putting out. One of you might think eventually think of something that's, well, genius!

Trivial point

RandomCyclist — Tue, 10 Mar 2009 22:24:22 -0700

You've made some very interesting points. The human cal/mi is the most suprising, so of course it has drawn flack. It certainly suprised me. But as you point we eat food made by modern ag, so we're actually using far more btus of energy input than we see on our plate. I'd be curious how much a calorie of healthy food - fruits, vegtables, nuts NOT bread or pasta costs to produce.

Assuming one has a shower available at commute's end, 15 mph for an unambitious cyclist and 20mph for one using the time for training is more realistic. That is speed while underway, not counting stops for intersections etc. A lazy commuter cyclist putting along at 10mph needs to have their 2 wheel licences revoked! (joke).

Bike cal/mi is not a single, fixed number. Much depends on whether the researchers have a clue about cycling. A traditional road bike with drop bars and 100psi tires which a serious commuter uses rolls far more easily than a fat tire mountain bike or an old 3-speed, both with extra drag from riding upright.

As for calories, while I like to think that I'm greener than all while on my bike it's unavoidable to eat more at some point. Sure, one can can go thousands of miles on the 10-25# of excess fat many people lug around, but once that's gone you have to replace the calories you burn off or you'd consume your internal organs and die. Worse than that, excercise raises your base metabolism, so you'll eat even more than the cycling calorie calc suggests.

But even if driving saved fuel over excercise, I would not suggest sacrificing your health to save fuel. If you're *honestly* that concerned about the enviroment, convert yourself and any offspring you have so far into soylent green and save untold harm to the environment. Sounds snarky, but no matter how much one "conserves" it is totally undone by having kids, sending them off to a college campus (which uses more energy to maintain the grounds for a month than the most wasteful family uses all year), having them see the world (unneccesary travel), have more kids and so forth.

The numbers vary a lot

brad — Mon, 12 Jan 2009 12:13:40 -0800

I worked from an article citing this study which calculated 530l per person within the ag sector, but over triple that in total. There are other similar articles around.

Holy cow: Walking consumes more gasoline than driving!

brad — Tue, 25 Mar 2008 18:47:03 -0700

Note to new readers: This article explores the consequences of using so much fuel to produce our food. If you come out of it thinking it’s telling you to drive rather than get some exercise, you didn’t read it! But if you like surprising numbers like this, check out the rest of my Going Green section and other sections.

In my growing research on transportation energy economics, I’ve come upon some rather astonishing research. I always enjoy debates on total cost analysis — trying to figure out the true energy cost of things, by adding in the energy spent elsewhere to make things happen. (For example, the energy to smelt the metals in your car adds quite a bit to its energy cost.)

Humans are modestly efficient. Walking, an average person burns about 100 Calories per mile at 3mph, or 300 per hour, while sitting for the same hour burns around 80 Calories just keeping you warm. In other words, the walking 3 miles uses about 220 extra Calories. Calories are kilocalories, and one Calorie/kcal is about 4 BTUs, 4200 joules or 1.63 watt-hours.

While walking 1 mile burns an extra 74 Calories, on a bicycle we’re much better. Biking one mile at 10mph takes about 38 extra calories over sitting. Again, this is the extra calories.

A gallon of gas has about 31,500 Calories in it, so you might imagine that you get 815 “mpg” biking and 400 “mpg” walking. Pretty good. (Unless you compare it to an electric scooter, which turns out to get the equivalent of 1200 mpg from pure electricity.)

But there’s a problem. We eat, on average about 2700 Calories/day in the USA, almost all of it produced by agribusiness. Which runs on fossil fuels. Fossil fuels provide the fertilizer. They run the machines. The process and transport and refrigerate the food. In many cases our food — cows — eats even more food produced with very high energy costs.

I’ve been digging around estimates, and have found that U.S. agriculture uses about 400 gasoline-gallon equivalents per American. Or 1.1 gallons per day, or about 10 Calories (40 BTU) from oil/gas for every Calorie of food. For beef, it’s far worse, as close to 40 Calories of oil/gas (160 BTU) are used to produce one Calorie of beefy goodness.

You can see where this is going. I’m not the first to figure it out, but it’s worth repeating. Your 3 mile walk burned 220 extra Calories over sitting, but drove the use of 2,200 Calories of fossil fuel. That’s 1/14th of a gallon of gasoline (9oz.) So you’re getting about 42 miles per gas-gallon of fossil fuel.

If you eat a lot of beef or other livestock, and want to consider your incremental food as having come from beef, it’s around 10 miles per gallon. A Hummer does better!

So yes, if you drive your Prius instead of walking it’s going to burn less fossil fuel. If 2 people drive in a more ordinary car it’s going to burn less fossil fuel than both of them walking.

Biking’s better. The average-diet cyclist is getting 85 miles per gallon of fossil fuel. Still better for 2 to share a Prius. The beefeater is, as before only 1/4 as good. At 21mpg he’s better than a Hummer, but not that much better.

This is a fuel to fuel comparison. The fuel burned in the cars is the same sort of fuel burned in the tractors. It has extra energy costs in its extraction and transport, but this applies equally to both cases. And yes, of course, the exercise has other benefits than getting from A to B. And we have not considered a number of the other external costs of the vehicle travel — but they still don’t make this revelation less remarkable. (And neither does this result suggest one should not still walk or bike, rather it suggests we should make our food more efficiently.)

And no, picking transit isn’t going to help. Transit systems, on average, are only mildly greener than cars. City buses, in fact, use the same energy per passenger mile as typical cars. Light rail is sometimes 2 and rarely even 3 times better than cars, but in some cities like San Jose, it uses almost twice as much energy per actual passenger than passenger cars do. Taking existing transit vehicles that are already running is green, of course, but building inefficient lines isn’t.

Many people take this idea as a condemnation of cycling or exercise. It isn’t. Cycling is my favourite exercise. It is a condemnation of how much fossil fuel is used in agriculture. And, to a much lesser extent, a wakeup call to people who eat the average diet that they can’t claim their human-powered travel as good for the planet — just good for them. What would be good for the planet would be to eat a non-agribusiness diet and also walk or bike. How your food is farmed is more important though, than where it comes from. It’s the farming, not the shipping, that’s the big energy eater.

Obviously if you were going to need the exercise anyway, doing it while getting from A to B is not going to burn extra oil. Human powered travel well above the need to exercise is the only thing that would hurt, if fueled by U.S. agriculture. And eating a high calorie diet and not exercising would be just as bad.

Happy eating!

What’s not wrong with these numbers

As I note, since most of us need to exercise anyway, this is not at all a condemnation of walking and cycling, but rather of the amount of fossil fuel that agriculture uses. However, a lot of people still find faults with this analysis that I don’t think are there.

No, it doesn’t matter that making the fuel costs energy. It’s (roughly) the same fuel going into the tractors as going into the gas tanks. We’re comparing fuel in tank to fuel in tank.
Yes, I do account for the fact that just eating or sitting consumes calories. This calculation is based on the extra calories that biking or walking take, compared to sitting in a car. The base “keep you alive” calories are not counted, but they do require more fossil fuel to create.
I don’t include the energy required to make a car, which ranges from 25% (Prius) to 7% (Hummer) of its lifetime energy usage. However, most cyclists and pedestrians still own cars, so this is still spent if it sits in the garage while you walk. And while a 2000lb car may take 60-100 times as much energy to make as a 30lb bike, this is not so large a difference if expressed per lifetime vehicle-mile.
This is based on the USA averages. Of course different food means different results, but doesn’t change this story, which is about the average eater.